Scrape wikipedia-science: 6474 new, 3240 updated, 9992 total (kb-cron)

data/en.wikipedia.org/wiki/AAALAC_International-0.md

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+---
+title: "AAALAC International"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/AAALAC_International"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:41.804867+00:00"
+instance: "kb-cron"
+---
+
+AAALAC International is a private, nonprofit organization headquartered in Frederick, Maryland, that promotes the humane treatment of animals in science through voluntary accreditation and assessment programs. The accreditation program started in 1965, when some veterinarians and researchers organized the American Association for Accreditation of Laboratory Animal Care, or AAALAC. In 1996, AAALAC changed its name to the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC International). The organization said the name change reflected the organization's growth in other countries and its commitment to enhancing life sciences and quality animal care around the world. Since 2016, the organization is officially known only by its acronym, AAALAC International. There are currently about 1,000 organizations worldwide accredited through its program.
+Along with meeting all applicable local and national regulations, AAALAC accredited institutions must also demonstrate that they are achieving the standards outlined in the Guide for the Care and Use of Laboratory Animals, a document published since 1996 by the National Research Council of the U.S. National Academy of Sciences. The Guide includes standards go beyond what is required by law.
+
+
+== See also ==
+Animal welfare
+Animal testing
+American Association for Laboratory Animal Science, a U.S. nonprofit organization
+Animal Welfare Act of 1966, a U.S. law
+Food Security Act of 1985, a U.S. law
+In vivo
+
+
+== References ==

data/en.wikipedia.org/wiki/Absolute_income_hypothesis-0.md

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+---
+title: "Absolute income hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Absolute_income_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:52.235761+00:00"
+instance: "kb-cron"
+---
+
+In economics, the absolute income hypothesis concerns how a consumer divides their disposable income between consumption and saving. It is part of the theory of consumption attributed to John Maynard Keynes. The American economist James Tobin (1918–2002) researched and developed this idea more extensively in the 1960s and 70s.
+
+
+== Background ==
+Keynes' General Theory in 1936 identified the relationship between income and consumption as a key macroeconomic relationship. Keynes asserted that real consumption (i.e. adjusted for inflation) is a function of real disposable income, which is total income net of taxes. As income rises, the theory asserts that consumption will also rise, but not necessarily at the same rate. When applied to a cross section of a population, rich people are expected to consume a lower proportion of their income than poor people.
+The marginal propensity to consume is present in Keynes' consumption theory and determines by what amount consumption will change in response to a change in income.
+While this theory has success modeling consumption in the short term, attempts to apply this model over a longer time frame have proven less successful. This has led to the absolute income hypothesis falling out of favor as the consumption model of choice for economists. Keynes' consumption function has come to be known as 'absolute income hypothesis' or 'absolute income theory'. His statement of the relationship between income and consumption was based on psychological law.
+
+
+== Model ==
+The model is
+
+  
+    
+      
+        
+          C
+          
+            t
+          
+        
+        =
+        α
+        +
+        λ
+        
+          Y
+          
+            t
+          
+        
+      
+    
+    {\displaystyle C_{t}=\alpha +\lambda Y_{t}}
+  
+
+where: 
+
+  
+    
+      
+        
+          C
+          
+            t
+          
+        
+      
+    
+    {\displaystyle C_{t}}
+  
+ is consumption at time t,
+
+  
+    
+      
+        α
+      
+    
+    {\displaystyle \alpha }
+  
+ is autonomous consumption, a constant,
+
+  
+    
+      
+        λ
+      
+    
+    {\displaystyle \lambda }
+  
+ is the marginal propensity to consume (
+  
+    
+      
+        0
+        <
+        λ
+        <
+        1
+      
+    
+    {\displaystyle 0<\lambda <1}
+  
+),
+
+  
+    
+      
+        
+          Y
+          
+            t
+          
+        
+      
+    
+    {\displaystyle Y_{t}}
+  
+ is disposable income at time t.
+The component 
+  
+    
+      
+        λ
+        
+          Y
+          
+            t
+          
+        
+      
+    
+    {\displaystyle \lambda Y_{t}}
+  
+ represents induced consumption.
+
+
+== See also ==
+Consumption function
+
+
+== Notes ==
+
+
+== References ==
+Keynes, John M. The General Theory of Employment, Interest and Money.  London: Macmillan, 1936.

data/en.wikipedia.org/wiki/Ad_hoc_hypothesis-0.md

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+---
+title: "Ad hoc hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Ad_hoc_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:53.374609+00:00"
+instance: "kb-cron"
+---
+
+In science and philosophy, an ad hoc hypothesis is a hypothesis added to a theory in order to save it from being falsified.
+For example, a person that wants to believe in leprechauns can avoid ever being proven wrong by using ad hoc hypotheses (e.g., by adding "they are invisible", then "their motives are complex", and so on).
+Often, ad hoc hypothesizing is employed to compensate for anomalies not anticipated by the theory in its unmodified form.
+
+
+== In the scientific community ==
+Scientists are often skeptical of theories that rely on frequent, unsupported adjustments to sustain them. This is because, if a theorist so chooses, there is no limit to the number of ad hoc hypotheses that they could add. Thus the theory becomes more and more complex, but is never falsified. This is often at a cost to the theory's predictive power, however. Ad hoc hypotheses are often characteristic of pseudoscientific subjects.
+Albert Einstein's addition of the cosmological constant to general relativity in order to allow a static universe was ad hoc. Although he later referred to it as his "greatest blunder", it may correspond to theories of dark energy.
+
+
+== See also ==
+Ad hoc
+Fringe science
+Russell's teapot
+Deferent and epicycle § Bad science
+No true Scotsman
+Special pleading
+The Structure of Scientific Revolutions
+Proofs and Refutations
+"The Dragon in My Garage"
+Paraconsistent logic
+Moving the goalposts
+
+
+== References ==
+
+
+== External links ==
+Ad hoc hypothesis at PhilPapers

data/en.wikipedia.org/wiki/Adipose_tissue_expandability_hypothesis-0.md

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+---
+title: "Adipose tissue expandability hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Adipose_tissue_expandability_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:55.612615+00:00"
+instance: "kb-cron"
+---
+
+The adipose tissue expandability hypothesis posits that metabolic dysregulation that appears to be caused by excess weight, such as type 2 diabetes and non-alcoholic fatty liver disease, are triggered when an individual's capacity for storing excess calories in the subcutaneous adipose tissue is exceeded. Each individual's capacity to store excess energy varies, so the threshold at which an individual begins to experience metabolic disease is not well captured by methods such as body mass index or body fat percentage. If a person has the ability to store a large amount of body fat without experiencing metabolic disturbance, this is known as metabolically healthy obesity.
+Although it was hypothesized that having a larger number of smaller adipocytes was correlated with the ability to store more fat, some evidence suggests the opposite—those with smaller adipocytes having a worse metabolic profile. The core factor, the inability to store excess fat in these cells, remains.
+
+
+== References ==

data/en.wikipedia.org/wiki/Admissible_heuristic-0.md

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+---
+title: "Admissible heuristic"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Admissible_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:17.054508+00:00"
+instance: "kb-cron"
+---
+
+In computer science, specifically in algorithms related to pathfinding, a heuristic function is said to be admissible if it never overestimates the cost of reaching the goal, i.e. the cost it estimates to reach the goal is not higher than the lowest possible cost from the current point in the path. In other words, it should act as a lower bound.
+It is related to the concept of consistent heuristics. While all consistent heuristics are admissible, not all admissible heuristics are consistent.
+
+
+== Search algorithms ==
+An admissible heuristic is used to estimate the cost of reaching the goal state in an informed search algorithm. In order for a heuristic
+to be admissible to the search problem, the estimated cost must always be lower than or equal to the actual cost of reaching the goal state. 
+The search algorithm uses the admissible heuristic to find an estimated 
+optimal path to the goal state from the current node. 
+For example, in A* search the evaluation function (where 
+
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+ is the current node) is:
+
+  
+    
+      
+        f
+        (
+        n
+        )
+        =
+        g
+        (
+        n
+        )
+        +
+        h
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)=g(n)+h(n)}
+  
+
+where
+
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+ = the evaluation function.
+
+  
+    
+      
+        g
+        (
+        n
+        )
+      
+    
+    {\displaystyle g(n)}
+  
+ = the cost from the start node to the current node
+
+  
+    
+      
+        h
+        (
+        n
+        )
+      
+    
+    {\displaystyle h(n)}
+  
+ = estimated cost from current node to goal.
+
+  
+    
+      
+        h
+        (
+        n
+        )
+      
+    
+    {\displaystyle h(n)}
+  
+ is calculated using the heuristic 
+function. With a non-admissible heuristic, the A* algorithm could 
+overlook the optimal solution to a search problem due to an 
+overestimation in 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+.
+
+
+== Formulation ==
+
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+ is a node
+
+  
+    
+      
+        h
+      
+    
+    {\displaystyle h}
+  
+ is a heuristic
+
+  
+    
+      
+        h
+        (
+        n
+        )
+      
+    
+    {\displaystyle h(n)}
+  
+ is cost indicated by 
+  
+    
+      
+        h
+      
+    
+    {\displaystyle h}
+  
+ to reach a goal from 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+
+  
+    
+      
+        
+          h
+          
+            ∗
+          
+        
+        (
+        n
+        )
+      
+    
+    {\displaystyle h^{*}(n)}
+  
+ is the optimal cost to reach a goal from 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+
+  
+    
+      
+        h
+        (
+        n
+        )
+      
+    
+    {\displaystyle h(n)}
+  
+ is admissible if, 
+  
+    
+      
+        ∀
+        n
+      
+    
+    {\displaystyle \forall n}
+  
+
+  
+    
+      
+        h
+        (
+        n
+        )
+        ≤
+        
+          h
+          
+            ∗
+          
+        
+        (
+        n
+        )
+      
+    
+    {\displaystyle h(n)\leq h^{*}(n)}
+  
+
+
+== Construction ==
+An admissible heuristic can be derived from a relaxed
+version of the problem, or by information from pattern databases that store exact solutions to subproblems of the problem, or by using inductive learning methods.
+
+
+== Examples ==
+Two different examples of admissible heuristics apply to the fifteen puzzle problem:
+
+Hamming distance
+Manhattan distance
+The Hamming distance is the total number of misplaced tiles. It is clear that this heuristic is admissible since the total number of moves to order the tiles correctly is at least the number of misplaced tiles (each tile not in place must be moved at least once). The cost (number of moves) to the goal (an ordered puzzle) is at least the Hamming distance of the puzzle.
+The Manhattan distance of a puzzle is defined as:
+
+  
+    
+      
+        h
+        (
+        n
+        )
+        =
+        
+          ∑
+          
+            all tiles
+          
+        
+        
+          
+            d
+            i
+            s
+            t
+            a
+            n
+            c
+            e
+          
+        
+        (
+        
+          tile, correct position
+        
+        )
+      
+    
+    {\displaystyle h(n)=\sum _{\text{all tiles}}{\mathit {distance}}({\text{tile, correct position}})}
+  
+
+Consider the puzzle below in which the player wishes to move each tile such that the numbers are ordered. The Manhattan distance is an admissible heuristic in this case because every tile will have to be moved at least the number of spots in between itself and its correct position.
+
+The subscripts show the Manhattan distance for each tile. The total Manhattan distance for the shown puzzle is:
+
+  
+    
+      
+        h
+        (
+        n
+        )
+        =
+        3
+        +
+        1
+        +
+        0
+        +
+        1
+        +
+        2
+        +
+        3
+        +
+        3
+        +
+        4
+        +
+        3
+        +
+        2
+        +
+        4
+        +
+        4
+        +
+        4
+        +
+        1
+        +
+        1
+        =
+        36
+      
+    
+    {\displaystyle h(n)=3+1+0+1+2+3+3+4+3+2+4+4+4+1+1=36}
+  
+
+
+== Optimality proof ==
+If an admissible heuristic is used in an algorithm that, per iteration, progresses only the path of lowest evaluation (current cost + heuristic) of several candidate paths, terminates the moment its exploration reaches the goal and, crucially, closes all optimal paths before terminating (something that's possible with A* search algorithm if special care isn't taken), then this algorithm can only terminate on an optimal path. To see why, consider the following proof by contradiction:
+Assume such an algorithm managed to terminate on a path T with a true cost Ttrue greater than the optimal path S with true cost Strue. This means that before terminating, the evaluated cost of T was less than or equal to the evaluated cost of S (or else S would have been picked). Denote these evaluated costs Teval and Seval respectively. The above can be summarized as follows,
+
+Strue < Ttrue
+Teval ≤ Seval
+If our heuristic is admissible it follows that at this penultimate step Teval = Ttrue because any increase on the true cost by the heuristic on T would be inadmissible and the heuristic cannot be negative. On the other hand, an admissible heuristic would require that Seval ≤ Strue which combined with the above inequalities gives us Teval < Ttrue and more specifically Teval ≠ Ttrue. As Teval and Ttrue cannot be both equal and unequal our assumption must have been false and so it must be impossible to terminate on a more costly than optimal path.
+As an example, let us say we have costs as follows:(the cost above/below a node is the heuristic, the cost at an edge is the actual cost)
+
+ 0     10   0   100   0
+START ----  O  ----- GOAL
+ |                   |
+0|                   |100
+ |                   | 
+ O ------- O  ------ O
+100   1    100   1   100
+
+So clearly we would start off visiting the top middle node, since the expected total cost, i.e. 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+, is 
+  
+    
+      
+        10
+        +
+        0
+        =
+        10
+      
+    
+    {\displaystyle 10+0=10}
+  
+. Then the goal would be a candidate, with 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+ equal to 
+  
+    
+      
+        10
+        +
+        100
+        +
+        0
+        =
+        110
+      
+    
+    {\displaystyle 10+100+0=110}
+  
+. Then we would clearly pick the bottom nodes one after the other, followed by the updated goal, since they all have 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+ lower than the 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+ of the current goal, i.e. their 
+  
+    
+      
+        f
+        (
+        n
+        )
+      
+    
+    {\displaystyle f(n)}
+  
+ is 
+  
+    
+      
+        100
+        ,
+        101
+        ,
+        102
+        ,
+        102
+      
+    
+    {\displaystyle 100,101,102,102}
+  
+. So even though the goal was a candidate, we could not pick it because there were still better paths out there. This way, an admissible heuristic can ensure optimality.
+However, note that although an admissible heuristic can guarantee final optimality, it is not necessarily efficient.
+
+
+== See also ==
+Consistent heuristic
+Heuristic function
+Search algorithm
+
+
+== References ==

data/en.wikipedia.org/wiki/Aestivation_hypothesis-0.md

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+---
+title: "Aestivation hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Aestivation_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:56.818197+00:00"
+instance: "kb-cron"
+---
+
+The aestivation hypothesis is a hypothesized solution to the Fermi paradox conceived in 2017 by Anders Sandberg, Stuart Armstrong and Milan M. Ćirković. The hypothesis, published on 27 April 2017, suggests advanced alien civilizations may be storing energy and aestivating (hibernating in times of heat instead of cold), until the universe cools to better make use of the stored energy to perform tasks.
+As the universe cools, the potential work producible by stored energy can increase by a multiplier of 1030 per Landauer's principle. If the goal of an advanced civilization is to maximize the number of calculations done, to generate information processing for tasks like mass-producing simulations, then aestivation would be purposeful to achieve this end.
+
+
+== Fermi paradox ==
+
+There is no reliable or reproducible evidence that aliens have visited Earth. No transmissions or evidence of intelligent extraterrestrial life have been detected or observed anywhere other than Earth in the Universe. This runs counter to the knowledge that the Universe is filled with a very large number of planets, some of which likely hold the conditions hospitable for life. Life typically expands until it fills all available niches. These contradictory facts form the basis for the Fermi paradox, of which the aestivation hypothesis is one proposed solution.
+
+
+== Intentions of alien civilizations ==
+Advanced alien civilizations may have intentions that differ considerably from one another and from humanity. If the intent is creating large amounts of "happiness", then energy resources may be used to generate perfect computer simulations of "the maximal number of maximally happy minds". If the intent is knowledge, resources may be focused on information storage. Such civilizations may go through a time of exploration and then remain dormant until the conditions of the universe are more energetically favorable to best achieve their objectives. While this may not achieve infinite value in terms of their intentions, the upper limit may still be extremely large.
+
+
+== Dispute ==
+The theory has been disputed by a subsequent paper by Charles H. Bennett, Robin Hanson and Jess Riedel, who claim the notion that more computations could be performed later in the universe's history is based on a misunderstanding of the physics of computation.
+
+
+== References ==

data/en.wikipedia.org/wiki/Affect_heuristic-0.md

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+---
+title: "Affect heuristic"
+chunk: 1/4
+source: "https://en.wikipedia.org/wiki/Affect_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:18.202032+00:00"
+instance: "kb-cron"
+---
+
+The affect heuristic is a  heuristic, a mental shortcut that allows people to make decisions and solve problems quickly and efficiently, in which current emotion—fear, pleasure, surprise, etc.—influences decisions. In other words, it is a type of heuristic in which emotional response, or "affect" in psychological terms, plays a lead role.  It is a subconscious process that shortens the decision-making process and allows people to function without having to complete an extensive search for information. It is shorter in duration than a mood, occurring rapidly and involuntarily in response to a stimulus. Reading the words "lung cancer" usually generates an affect of dread, while reading the words "mother's love" usually generates a feeling of affection and comfort.  The affect heuristic is typically used while judging the risks and benefits of something, depending on the positive or negative feelings that people associate with a stimulus. It is the equivalent of "going with your gut". If their feelings towards an activity are positive, then people are more likely to judge the risks as low and the benefits high. On the other hand, if their feelings towards an activity are negative, they are more likely to perceive the risks as high and benefits low.
+
+== Concept ==
+The theory of affect heuristic is that a human being's affect can influence how he or she makes decisions. Research has shown that risk and benefits are negatively correlated in people's minds. This was found after researchers found that the inverse relationship between perceived risk and perceived benefit of an activity was linked to the strength of positive or negative affect associated with the activity as measured by rating the activity on bipolar scales (e.g. good/bad). This implies that people base their judgements of an activity or a technology not only on what they think about it, but also on how they feel about it.  The affect heuristic gained early attention in 1980 when Robert B. Zajonc argued that affective reactions to stimuli are often the first reaction which occur automatically and subsequently influencing the way in which we process and judge information. The affect heuristic received more recent attention when it was used to explain the unexpected negative correlation between benefit and risk perception. Finucane, Alhakami, Slovic and Johnson theorized in 2000 that a good feeling towards a situation (i.e., positive affect) would lead to a lower risk perception and a higher benefit perception, even when this is logically not warranted for that situation. This implies that a strong emotional response to a word or other stimulus might alter a person's judgment. He or she might make different decisions based on the same set of facts and might thus make an illogical decision. Overall, the affect heuristic is of influence in nearly every decision-making arena.
+
+=== Theoretical accounts of affect ===
+An alternative thought to the “gut feeling” response is Antonio Damasio's somatic marker hypothesis. It is the opinion that thought is made largely from images which include perceptual and symbolic representations. These images then become “marked” by positive or negative feelings linked directly or indirectly to somatic states. When a negative somatic marker is linked to an image of a future outcome, it sounds an alarm in the brain. When a positive marker is linked to an image, it becomes a signal of incentive. He hypothesized that somatic markers increase the accuracy of the decision process and the absence of these markers, mostly seen in people with certain types of brain damage, degrades the ability to make good decisions. This hypothesis arose when observing patients with damage to their prefrontal cortex who had severe impairments in personal and social decision-making despite their other abilities.
+
+== Thought and feeling ==
+It has been argued by researchers that people use affect heuristics as a first response to an issue, they rely on spontaneous affective reactions which make it more efficient than having to research and analyze external information. Slovic, Finucane, Peters and MacGregor (2005) contrast two modes of thinking: the analytic system and the experiential system. The analytic system, also referred to as the rational system, is thought that is considered to be slow and requires effort; it requires consciousness, probabilities, logical reasoning, and substantial evidence. The experiential system is the exact opposite. It is intuitive and mostly automatic which makes it more convenient for people because it does not require effort or consciousness. It relies on images, metaphors, and narratives which are then used to estimate the probability of a hazard. This is due to the experience of affect, in other words, a “gut feeling.” Multiple studies including the one done by Miller and Ireland (2005) show how "gut feeling" or intuitive decisions affect various executives and managers of many companies. Many of the individuals studied use intuition as an effective approach to making important decisions. The experimenters' goal is to evaluate the risk and benefits of using intuition. Their results show that this is a troublesome decision tool. Affective reactions that accompany judgements are not necessarily voluntary, but are automatic responses. Zajonc states that “one might be able to control the expression of emotion, but not the experience of it itself.”  However, he also clarifies that feelings are not free of thought and that thoughts are not free of feeling. The experiential system also takes past experiences into account. In other words, if a person has already experienced a certain issue, he or she is more likely to take more precautions towards the issue.
+
+== Experimental findings ==
+Many studies have been done to further look into affect heuristics and many have found that these heuristics shape our attitudes and opinions towards our decisions, especially risk perception. These studies demonstrate how affect is an important characteristic of the decision-making process in many different domains and aspects as well as how it can lead to a strong conditioner of preference. As demonstrated below, affect is independent of cognition which indicate that there are conditions where affect does not require cognition.

data/en.wikipedia.org/wiki/Affect_heuristic-1.md

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+---
+title: "Affect heuristic"
+chunk: 2/4
+source: "https://en.wikipedia.org/wiki/Affect_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:18.202032+00:00"
+instance: "kb-cron"
+---
+
+=== Subliminal affective response ===
+The cause of affect does not necessarily have to be consciously perceived. A study conducted by Winkielman, Zajonc and Schwarz (1997) demonstrated the speed at which an affective reaction can influence judgements. To do this they used a subliminal priming paradigm where participants were "primed" through exposure to either a smiling face, a frowning face, or a neutral polygon presented at about 1⁄250  of a second. This was considered an amount of time where the nature of the stimuli could not be recalled. Participants were then exposed to an ideograph (e.g. a Chinese character) for two seconds and asked to rate the ideograph on a scale of liking. Researchers found that participants preferred the ideograph preceded with a smiling face as opposed to those preceded by a frowning face or neutral polygon despite the fact that the smiling face was only shown for 1⁄250 of a second.
+The same experiment demonstrated the persistence of initial affect. During a second session, participations were primed with the same characters, but these characters were preceded by a different face that they were not previously exposed to (e.g. those previously exposed to the smiling face were now exposed to the neutral polygon). Participants continued to show preference for the characters based on the first association, even though the second exposure was preceded by a different affective stimulus.  In other words, the second priming was ineffective because the effects of the first priming still remained. If the participant liked a character following exposure to a smiling face, they would continue to like the character even when it was preceded by a frowning face during the second exposure. (The experimental outcome was statistically significant and adjusted for variables such as non-affective preference for certain characters).
+
+=== Insensitivity to numbers ===
+Sometimes affective responses to certain stimuli are a result of a lack of sensitivity to other factors, for example, numbers. Slovic and Peters (2006) did a study on psychophysical numbing, the inability to discriminate change in a physical stimulus as the magnitude of the stimulus increases, and found that students more strongly supported an airport-safety measure that was expected to save a  high percentage of 150 lives at risk as opposed to a measure that was expected to save 150 lives. This is thought to have occurred because although saving 150 lives is good, it is somewhat harder to comprehend and thus the decision comes from the positive feeling associated with the higher percentage.
+
+=== The influence of time ===
+Research has been conducted in the influence that time plays in decision-making. In two experiments, Finucane, Alhakami, Slovic and Johnson (2000) studied the affect heuristic under time pressure and the influence that providing risk and benefit information has on the affect heuristic. The researchers compared individuals under no time pressure and those with time pressure. They predicted that individuals under time pressure would rely more heavily on their affect in order to be more efficient in their responses whereas those under no time pressure would use more logic in their decision-making. To do this, university students were randomly assigned to one of the two conditions (time pressure or no time pressure) and one of the two counterbalancing orders (risk judgements followed by benefit judgements or vice versa). They were then given a task in which they had to make judgements about the risk or benefit of certain activities and technologies. As predicted, individuals in the time-pressure condition took less time to make risk judgements than did individuals in the no time pressure condition. In the second experiment, students again had to make judgements about certain activities, but this time were given additional information about the risk and benefits. Information was framed as being high risk, low risk, high benefit or low benefit. The researchers found that this additional information did in fact influence their judgements.
+Two similar studies were conducted by Wilson and Arvai in 2006, in which they also looked at the affect heuristic affects high and low risk options. These experiments examine the affect heuristic and the “evaluability hypothesis”, the joint evaluation when options are evaluated in a side-by-side comparison and separate evaluation where options are evaluated on their own. They take this concept and discuss how it relates to the affect heuristic by specifically looking at making traits of an option more or less meaningful in terms of the context of choice, more specifically, affect. To examine this relationship more closely, they conducted two experiments where participants received quantitative information about the nature of risks and were placed in one of two groups: affect-poor combined with high risks and affect-rich combined with low risks. In their first study, they looked how the influence of affect on evaluability in joint evaluations as compared to separate evaluations. To this, participants were asked to make choices about the affect-rich problem of crime and the affect-poor problem of deer overpopulation. Participants were asked to rate how they perceived crime and deer overpopulation by rating  on a scale from "very good" to "very bad." They found that participants ignored the quantitative information and focused on the affect characteristics.

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+---
+title: "Affect heuristic"
+chunk: 3/4
+source: "https://en.wikipedia.org/wiki/Affect_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:18.202032+00:00"
+instance: "kb-cron"
+---
+
+=== Fear appeals ===
+Health campaigns often use “fear appeals” to grab the attention of their audience.  Fear appeals are a type of advertising that specifically uses methods of creating anxiety in the consumer which results in the consumer wanting to cure this fear by purchasing the product. In a study by Averbeck, Jones, and Robertson (2011), researchers look at how prior knowledge influences one's response to fear appeals. Surveys were distributed which manipulated prior knowledge as low or high and two different topics: sleep deprivation or spinal meningitis. Various scale were used to test how prior knowledge affects certain health-related issues. Researchers found that individuals who had prior knowledge in a certain subject exhibited less fear and were least likely to fall prey to the affect heuristic as opposed to individuals that did not have prior knowledge who exhibited more fear and were more likely to fall prey.
+Another example of how fear appeals are used in marketing today is through the findings presented in the experiment by Schmitt and Blass (2008). They produced two versions of an anti-smoking film. One contained high fear arousal and one did not. Out of the participants (46 non-smoking students and 5 smoking students), those who viewed the high fear-arousal version expressed stronger anti-smoking behavioral intentions than those who viewed the low fear-arousal version.
+
+=== Climate change ===
+Research has shown that Americans are aware of climate change, but do not consider it to be a serious problem due to the lack of an affective response. Many people report as not having experienced the consequences of climate change or that it is a long-term consequence that will not happen in the near future. Therefore, it is considered to be of lower priority and not much is done as a solution to global climate change.
+
+=== Risk communication ===
+Research on the affect heuristic had its origin in risk perception. Communicating risk is meant to improve the correspondence between the magnitude of the risk of an issue and the magnitude to which people respond to that risk. Affect, specifically negative affect, is an important method for increasing perceived risk considering its influences on perceived risk and thus has been utilized as essential for communicating risk to the public.
+Raising risk awareness is thought to be increased when risk information is presented in the form of frequences (e.g. “Within 40 years there is a 33% probability of flood”) or probabilities (e.g. “Each year there is a 1% probability of flood). This method is thought to evoke an affective response which then increases the availability of risk which results in greater perceived risk. This demonstrates how the way in which information is presented influences the way in which people interpret the information, more specifically, potential risks. Research also shows that people's financial risk taking is affected by their emotional state,
+The affect heuristic is certainly evident in product innovations we see in the market. The processes consumers use to weigh the potential risk and benefits associated with purchasing such innovations are in constant motion. A study by Slovic and King (2014) tries to explain this specific phenomenon. Their experiment addresses the extent to which feelings dominate early perceptions of new products. Participants were exposed to three innovations in pretest and posttest design. Through this study, they concluded that risks and benefits associated with innovations are related to the consumer's evaluations of the products.
+
+==== Cancer ====
+Researchers have looked at the affective and experiential modes of thinking in terms of cancer prevention. Research has shown that affect plays a significant role in whether people choose to get screened for certain types of cancer. Current research is now looking into how to communicate the risks and benefits of cancer prevention and treatment options. So far research has shown that the way in which information is framed does play a role in the way in which the information is interpreted. Research has also shown that treatment options may not have significant meaning to patients unless it has an affective connection. It is for this reason that researchers are looking into using affective coding such as icon arrays to make numerical information easier to understand and process.
+
+=== Air Pollution ===
+An experiment composed by Hine and Marks (2007) examines the role of affect heuristics in maintaining wood-burning behavior. The individuals analyzed in this study were 256 residents of a small Australian city where high levels of wood smoke pollution are present. With the negative effects of air pollution evident, their studies found that individuals who used wood heaters exhibited less support for wood smoke control policies. These individuals were aware that their wood heaters were part of the problem. Even with that awareness, their positive affections and emotions towards wood heating trumped all negative evidence for it.

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+---
+title: "Affect heuristic"
+chunk: 4/4
+source: "https://en.wikipedia.org/wiki/Affect_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:18.202032+00:00"
+instance: "kb-cron"
+---
+
+=== Smiling ===
+Research has been done on how smiling can cause affective responses and thus influence our opinions of others. An experiment by LaFrance and Hecht (1995) investigated  whether a smiling target would elicit more leniency than those that do not. Participants judged a case of potential academic misconduct and were asked to rate a list of subjects. Materials included photos of a female target either showing a neutral expression, felt smile, false smile, or miserable smile. Researchers found that the student pictured as smiling received less punishment than did the student who did not smile despite the fact that the smiling student was not seen as less guilty. They did not find a significant difference between the different smiles. Smiling students were also rated as more trustworthy, honest, genuine, good, obedient, sincere, and admirable compared to the student that did not smile.
+To the previous studies evidence, there is further evidence on the effect of smiling on a person’s perception. They contain it in the experiment by Delevati and Cesar (1994). Brazilian undergraduates perceived a slide of a male and female person. Smiling faces were portrayed and non-smiling faces were portrayed. The participants used 12 different adjectives to judge the portraits. Results showed those persons showing a smile received more favorable perceptions than those who did not. Generally speaking, a smiling person can produce warmer feelings in the perceiver than the non-smiling person.
+
+=== Memory load ===
+Researchers have studied how one's memory load increases one's chances of using the affect heuristic. In a study by Shiv and Fedorikhin (1999), participants were asked to either memorize a two-digit number (low cognitive demand) or a seven-digit number (high cognitive demand). Participants were then asked to enter another room where they would report their number. On the way there, they were asked for their preference for two snacks: chocolate cake (more favorable affect, less favorable cognition) or fruit salad (less favorable affect, more favorable cognition). Researchers predicted that participants given the seven-digits to remember (high cognitive load) would reduce their deliberation process due to having to remember a large amount of information. This would increase the chances of these participants choosing the cake over the fruit salad due to it being the more affectively favorable option. This hypothesis proved true with participants choosing the chocolate cake 63% of the time when given a high cognitive load and only 41% when given a low cognitive load. In the same study they also tested the impulsiveness of the participants in moderating the effects of processing-resources of choice and at the time they were asked for their preference for the two snacks high cognitive demand chose the chocolate cake 84.2%. This provides evidence that people's decisions  can be influenced by affect heuristic in a relatively spontaneous manner from the stimulus, with little involvement of higher-order cognitive demand.
+
+=== Lasting effects ===
+Another common situation involving affect heuristic is where a strong, emotional first impression can inform a decision, even if subsequent evidence weight cognitively against the original decision made. In a study by Sherman, Kim and Zajonc (1998), they investigated how long the induced effects of an affective response could last. Participants were asked to study Chinese characters and their English meanings. Half of the meanings were positive (e.g. beauty) and the other half negative (e.g. disease). Participants were then tested on these meanings, which was followed by a task in which they were given pairs of characters and asked to choose which character they preferred. Researchers found that participants preferred the character with a positive meaning.
+In the same experiment, participants were given a new task where the characters were presented with a neutral meaning (e.g. linen) and participants were told that these were the true meanings of the character. The testing procedure was the same and despite exposing participants with the new meanings, their preferences in characters remained the same. Characters that were paired with positive meanings continued to be preferred.
+
+== Disadvantages ==
+While heuristics can be helpful in many situations, it can also lead to biases which can result in poor decision-making habits. Like other heuristics, the affect heuristic can provide efficient and adaptive responses, but relying on affect can also cause decisions to be misleading.
+
+=== Smoking ===
+Studies have looked at how the affect influences smoking behavior. Smokers tend to act experientially in the sense that they give little conscious thought to the risks before they start. It is usually as a result of affective responses in the moment that occur when seeing others partake in the behavior. Epstein (1995) found that there has been quite a bit of manipulation of consumers when it comes to packaging and marketing products. This is especially the case with tobacco companies. Research has shown that cigarette advertisements were designed to increase the positive affect associated with smoking and decrease the perceptions of risk. Therefore, seeing this advertisement could lead people astray to start smoking because of its induced appeal. In a study by Slovic et al. (2005), he released a survey to smokers in which he asked “If you had it to do all over again, would you start smoking?” and more than 85% of adult smokers and about 80% of young smokers (between the ages of 14 and 22) answered “No.” He found that most smokers, especially those that start at a younger age, do not take the time and think about how their future selves will perceive the risks associated with smoking. Essentially, smokers give little conscious thought to smoking before they start and it is usually after they have started smoking and have become addicted that they learn new information about health risk.
+
+== References ==
+
+== Further reading ==
+Slovic, Paul; Melissa Finucane; Ellen Peters; Donald G. MacGregor (2014). "The Affect Heuristic" (PDF). European Journal of Operational Research. 55 (6): 527–32. doi:10.1111/sjop.12166. PMID 25243906.
+Thomas Gilovich; Dale Griffin; Daniel Kahneman, eds. (2002). Heuristics and Biases: The Psychology of Intuitive Judgment. Cambridge University Press. ISBN 978-0-521-79679-8.
+Shefrin, Hersh (2002). Behavioral Corporate Finance: Decisions that create value. McGraw-Hill. pp. 2, 10, 164, 40–42, 60–61, 69. ISBN 978-0-07-284865-6.

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+---
+title: "Alvarez hypothesis"
+chunk: 1/3
+source: "https://en.wikipedia.org/wiki/Alvarez_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:58.010084+00:00"
+instance: "kb-cron"
+---
+
+The Alvarez hypothesis posits that the mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the impact of a large asteroid on the Earth. Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an updated value of 66 million years. Evidence indicates that the asteroid fell in the Yucatán Peninsula, at Chicxulub, Mexico. The hypothesis is named after the father-and-son team of scientists Luis and Walter Alvarez, who first suggested it in 1980. Shortly afterwards, and independently, the same was suggested by Dutch paleontologist Jan Smit.
+In March 2010, an international panel of scientists endorsed the asteroid hypothesis, specifically the Chicxulub impact, as being the cause of the extinction. A team of 41 scientists reviewed 20 years of scientific literature and in so doing also ruled out other theories such as massive volcanism. They had determined that a space rock 10–15 km (6–9 mi) in diameter hurtled into earth at Chicxulub. For comparison, the Martian moon Phobos has a diameter of 22 km (14 mi), and Mount Everest is just under 9 km (5.6 mi). The collision would have released the same energy as 100,000,000 megatonnes of TNT (4.2×1023 J), over a billion times the energy of the atomic bombs dropped on Hiroshima and Nagasaki.
+A 2016 drilling project into the peak ring of the crater strongly supported the hypothesis, and confirmed various matters that had been unclear until that point. These included the fact that the peak ring comprised granite (a rock found deep within the Earth) rather than typical sea floor rock, which had been shocked, melted, and ejected to the surface in minutes, and evidence of colossal seawater movement directly afterwards from sand deposits. Crucially, the cores also showed a near-complete absence of gypsum, a sulfate-containing rock, which would have been vaporized and dispersed as an aerosol into the atmosphere, confirming the presence of a probable link between the impact and global longer-term effects on the climate and food chain.
+
+== History ==
+
+In 1980, a team of researchers led by Nobel prize-winning physicist Luis Alvarez, his son geologist Walter Alvarez, and chemists Frank Asaro and Helen Vaughn Michel, discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary (K–Pg boundary, formerly called Cretaceous–Tertiary or K–T boundary) contain a concentration of iridium hundreds of times greater than normal.
+Previously, in a 1953 publication, geologists Allan O. Kelly and Frank Dahille analyzed global geological evidence suggesting that one or more giant asteroids impacted the Earth, causing an angular shift in its axis, global floods, firestorms, atmospheric occlusion, and the extinction of the dinosaurs. There were other earlier speculations on the possibility of an impact event, but without strong confirming evidence.
+
+== Evidence and projects ==

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+---
+title: "Alvarez hypothesis"
+chunk: 2/3
+source: "https://en.wikipedia.org/wiki/Alvarez_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:58.010084+00:00"
+instance: "kb-cron"
+---
+
+The location of the impact was unknown when the Alvarez team developed their hypothesis, but later scientists discovered the Chicxulub Crater in the Yucatán Peninsula, now considered the likely impact site.
+Paul Renne of the Berkeley Geochronology Center has reported that the date of the asteroid event is 66,038,000 years ago, plus or minus 11,000 years, based on Ar-Ar dating.  He further posits that the mass extinction of dinosaurs occurred within 33,000 years of this date.
+In April 2019, a paper was published in PNAS which describes evidence from a fossil site in North Dakota that the authors say provides a "postimpact snapshot" of events after the asteroid collision "including ejecta accretion and faunal mass death". The team found that the tektites that had peppered the area were present in amber found on the site and were also embedded in the gills of about 50 percent of the fossil fish. They were also able to find traces of iridium. The authors – who include Walter Alvarez – postulate that shock of the impact, equivalent to an earthquake of magnitude 10 or 11, may have led to seiches, oscillating movements of water in lakes, bays, or gulfs, that would have reached the site in North Dakota within minutes or hours of the impact. This would have led to the rapid burial of organisms under a thick layer of sediment. Coauthor David Burnham of the University of Kansas was quoted as saying, "They’re not crushed, it’s like an avalanche that collapses almost like a liquid, then sets like concrete. They were killed pretty suddenly because of the violence of that water. We have one fish that hit a tree and was broken in half."
+According to a high-resolution study of fossilized fish bones published in 2022, the Cretaceous-Paleogene asteroid which caused mass extinction impacted during the Northern Hemisphere spring.
+In 2016, a scientific drilling project drilled deep into the peak ring of the Chicxulub impact crater, to obtain rock core samples from the impact itself. The discoveries were widely seen as confirming current theories related to both the crater impact, and its effects. They confirmed that the rock composing the peak ring had been subjected to immense pressures and forces and had been melted by immense heat and shocked by immense pressure from its usual state into its present form in just minutes; the fact that the peak ring was made of granite was also significant, since granite is not a rock found in sea-floor deposits, it originates much deeper in the Earth and had been ejected to the surface by the immense pressures of impact; that gypsum, a sulfate-containing rock that is usually present in the shallow seabed of the region, had been almost entirely removed and must therefore have been almost entirely vaporized and entered the atmosphere, and that the event was immediately followed by a huge megatsunami (a massive movement of sea waters) sufficient to lay down the largest known layer of sand separated by grain size directly above the peak ring.
+These strongly support the hypothesis that the impactor was large enough to create a 120-mile peak ring, to melt, shock and eject basement granite from the mid-crust deep within the Earth, to create colossal water movements, and to eject an immense quantity of vaporized rock and sulfates into the atmosphere, where they would have persisted for a long time.  This global dispersal of dust and sulfates would have led to a sudden and catastrophic effect on the climate worldwide, large temperature drops, and devastated the food chain.
+
+== Alternative theories ==

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+title: "Alvarez hypothesis"
+chunk: 3/3
+source: "https://en.wikipedia.org/wiki/Alvarez_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:58.010084+00:00"
+instance: "kb-cron"
+---
+
+Although a 2010 paper published in Science that declared that the extinction of the dinosaurs was caused by Chicxulub was co-authored by 41 scientists, dozens of other scientists challenged both the paper's methods and its conclusions. A leading critic of the Alvarez hypothesis is Gerta Keller, who has focused on Deccan Traps volcanism as a likely cause of a more gradual extinction. Despite the fact that the Alvarez hypothesis has overwhelming support from the scientific community, Keller has continued to advocate for research into alternate theories. The Deccan Traps theory was first proposed in 1978 by geologist Dewey McLean but quickly lost traction. The Deccan Traps are an area of volcanic flood basalts in Western India spanning ~1.3 million square kilometers that were created by massive volcanic activity during the same time period in which the Chicxulub impact occurred. Prior to Keller's research, the timeframe of the Deccan Traps' eruptions had a significantly large range of error, making it difficult to draw strong conclusions regarding their connection to the K-Pg extinction. In a 2014 report, Keller and her colleagues used uranium-lead zircon geochronology to more accurately identify the eruptions as occurring both within a span of one million years and around 250,000 years prior to the K-Pg boundary. Keller additionally determined that ocean temperatures rose seven to nine degrees Celsius during the most significant period of the Deccan eruptions. Along with ocean acidification, ozone reduction, acid rain, and a release of harmful gases, she asserts that these conditions were sufficient to have initiated the mass extinction. Keller has specifically rejected the Alvarez hypothesis, pointing to evidence she gathered from the Chicxulub crater in 2009 revealing that twenty inches of sediment separates the impact from the extinction. The finding suggests that the impact occurred 200,000 to 300,000 years before the K-Pg extinction, a period far too large for the two to be correlated. This, however, contrasts the range of 33,000 years determined by Paul Renne in 2015, as well the more recent assertion that a tsunami generated by the impact created the unusual sediment layer. Keller additionally claims that the impact did not cause as much ecological damage as is widely believed, and she determined that many foraminifera species began to decline well before the impact event occurred. Her 2009 project revealed that the 52 species found in the sediment prior to the impact were present in the sediment following it, suggesting that the impact caused minimal extinction.
+A more recent theory combining both Deccan volcanism and the impact hypothesis has been developed by teams at UC Berkeley led by Paul Renne and Mark Richards. This theory proposes that the impact itself instigated the most intense period of Deccan eruptions, both of which had devastating effects contributing to the K-Pg extinction. Renne and Richards calculated that the Chicxulub impact was capable of producing seismic activity strong enough to initiate volcanic eruptions. They determined that the largest period of Deccan volcanic eruptions, or the Wai subgroup, occurred 50,000 to 100,000 years after the Chicxulub impact, which is consistent with theoretical predictions modeling the length of time after which eruptions should occur. The group also confirmed that the length of time between the extinction and subsequent biological recovery was consistent with the length of Deccan volcanic activity, proposing that the eruptions paused the recovery of the marine ecosystems destroyed by the impact.
+Debate regarding the cause of the K-Pg extinction has proven to be extremely controversial among researchers, and the resilience of its intensity has earned it the moniker of the "dinosaur wars." Criticism is unusually harsh, targeting not only research findings but the credibility and integrity of the scientists themselves. Verbal accusations have been thrown both by and toward many prominent researchers including Gerta Keller and Luis Alvarez, discouraging civil debate and in some cases threatening careers. Walter Alvarez is an active member of the UC Berkeley team researching the connection between Deccan volcanism and the Chicxulub impact.
+
+== References ==

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+---
+title: "Analysis of competing hypotheses"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Analysis_of_competing_hypotheses"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:59.135316+00:00"
+instance: "kb-cron"
+---
+
+The analysis of competing hypotheses (ACH) is a methodology for evaluating multiple competing hypotheses for observed data. It was developed by Richards (Dick) J. Heuer, Jr., a 45-year veteran of the Central Intelligence Agency, in the 1970s for use by the Agency. ACH is used by analysts in various fields who make judgments that entail a high risk of error in reasoning. ACH aims to help an analyst overcome, or at least minimize, some of the cognitive limitations that make prescient intelligence analysis so difficult to achieve.
+ACH was a step forward in intelligence analysis methodology, but it was first described in relatively informal terms. Producing the best available information from uncertain data remains the goal of researchers, tool-builders, and analysts in industry, academia and government. Their domains include data mining, cognitive psychology and visualization, probability and statistics, etc. Abductive reasoning is an earlier concept with similarities to ACH.
+
+== Process ==
+Heuer outlines the ACH process in considerable depth in his book, Psychology of Intelligence Analysis. It consists of the following steps:
+
+Hypothesis – The first step of the process is to identify all potential hypotheses, preferably using a group of analysts with different perspectives to brainstorm the possibilities. The process discourages the analyst from choosing one "likely" hypothesis and using evidence to prove its accuracy. Cognitive bias is minimized when all possible hypotheses are considered.
+Evidence – The analyst then lists evidence and arguments (including assumptions and logical deductions) for and against each hypothesis.
+Diagnostics – Using a matrix, the analyst applies evidence against each hypothesis in an attempt to disprove as many theories as possible. Some evidence will have greater "diagnosticity" than other evidence—that is, some will be more helpful in judging the relative likelihood of alternative hypotheses. This step is the most important, according to Heuer. Instead of looking at one hypothesis and all the evidence ("working down" the matrix), the analyst is encouraged to consider one piece of evidence at a time, and examine it against all possible hypotheses ("working across" the matrix).
+Refinement – The analyst reviews the findings, identifies any gaps, and collects any additional evidence needed to refute as many of the remaining hypotheses as possible.
+Inconsistency – The analyst then seeks to draw tentative conclusions about the relative likelihood of each hypothesis. Less consistency implies a lower likelihood. The least consistent hypotheses are eliminated. While the matrix generates a definitive mathematical total for each hypothesis, the analyst must use their judgment to make the final conclusion. The result of the ACH analysis itself must not overrule analysts' own judgments.
+Sensitivity – The analyst tests the conclusions using sensitivity analysis, which weighs how the conclusion would be affected if key evidence or arguments were wrong, misleading, or subject to different interpretations. The validity of key evidence and the consistency of important arguments are double-checked to assure the soundness of the conclusion's linchpins and drivers.
+Conclusions and evaluation – Finally, the analyst provides the decisionmaker with his or her conclusions, as well as a summary of alternatives that were considered and why they were rejected. The analyst also identifies milestones in the process that can serve as indicators in future analyses.
+
+== Strengths ==
+Some benefits of doing an ACH matrix are:
+
+It is auditable.
+It is widely believed to help overcome cognitive biases, though there is a lack of strong empirical evidence to support this belief.
+Since the ACH requires the analyst to construct a matrix, the evidence and hypotheses can be backtracked. This allows the decisionmaker or other analysts to see the sequence of rules and data that led to the conclusion.
+
+== Weaknesses ==
+Weaknesses of doing an ACH matrix include:
+
+The process to create an ACH is time-consuming.
+The ACH matrix can be problematic when analyzing a complex project.
+It can be cumbersome for an analyst to manage a large database with multiple pieces of evidence.
+Evidence also presents a problem if it is unreliable.
+The evidence used in the matrix is static and therefore it can be a snapshot in time.
+Especially in intelligence, both governmental and business, analysts must always be aware that the opponent(s) is intelligent and may be generating information intended to deceive. Since deception often is the result of a cognitive trap, Elsaesser and Stech use state-based hierarchical plan recognition (see abductive reasoning) to generate causal explanations of observations. The resulting hypotheses are converted to a dynamic Bayesian network and value of information analysis is employed to isolate assumptions implicit in the evaluation of paths in, or conclusions of, particular hypotheses. As evidence in the form of observations of states or assumptions is observed, they can become the subject of separate validation. Should an assumption or necessary state be negated, hypotheses depending on it are rejected. This is a form of root cause analysis.
+According to social constructivist critics, ACH also fails to stress sufficiently (or to address as a method) the problematic nature of the initial formation of the hypotheses used to create its grid. There is considerable evidence, for example, that in addition to any bureaucratic, psychological, or political biases that may affect hypothesis generation, there are also factors of culture and identity at work. These socially constructed factors may restrict or pre-screen which hypotheses end up being considered, and then reinforce confirmation bias in those selected.
+Philosopher and argumentation theorist Tim van Gelder has made the following criticisms:

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+---
+title: "Analysis of competing hypotheses"
+chunk: 2/2
+source: "https://en.wikipedia.org/wiki/Analysis_of_competing_hypotheses"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:58:59.135316+00:00"
+instance: "kb-cron"
+---
+
+ACH demands that the analyst makes too many discrete judgments, a great many of which contribute little if anything to discerning the best hypothesis
+ACH misconceives the nature of the relationship between items of evidence and hypotheses by supposing that items of evidence are, on their own, consistent or inconsistent with hypotheses.
+ACH treats the hypothesis set as "flat", i.e. a mere list, and so is unable to relate evidence to hypotheses at the appropriate levels of abstraction
+ACH cannot represent subordinate argumentation, i.e. the argumentation bearing up on a piece of evidence.
+ACH activities at realistic scales leave analysts disoriented or confused.
+Van Gelder proposed hypothesis mapping (similar to argument mapping) as an alternative to ACH.
+
+=== Structured analysis of competing hypotheses ===
+The structured analysis of competing hypotheses offers analysts an improvement over the limitations of the original ACH. The SACH maximizes the possible hypotheses by allowing the analyst to split one hypothesis into two complex ones.
+For example, two tested hypotheses could be that Iraq has WMD or Iraq does not have WMD. If the evidence showed that it is more likely there are WMDs in Iraq then two new hypotheses could be formulated: WMD are in Baghdad or WMD are in Mosul. Or perhaps, the analyst may need to know what type of WMD Iraq has; the new hypotheses could be that Iraq has biological WMD, Iraq has chemical WMD and Iraq has nuclear WMD. By giving the ACH structure, the analyst is able to give a nuanced estimate.
+
+=== Other approaches to formalism ===
+One method, by Valtorta and colleagues uses probabilistic methods, adds Bayesian analysis to ACH. A generalization of this concept to a distributed community of analysts lead to the development of CACHE (the Collaborative ACH Environment), which introduced the concept of a Bayes (or Bayesian) community. The work by Akram and Wang applies paradigms from graph theory.
+Other work focuses less on probabilistic methods and more on cognitive and visualization extensions to ACH, as discussed by Madsen and Hicks. DECIDE, discussed under automation is visualization-oriented.
+Work by Pope and Jøsang uses subjective logic, a formal mathematical methodology that explicitly deals with uncertainty. This methodology forms the basis of the Sheba technology that is used in Veriluma's intelligence assessment software.
+
+== Software ==
+
+A few online and downloadable software tools help automate the ACH process. These programs leave a visual trail of evidence and allow the analyst to weigh evidence.
+
+PARC ACH 2.0 was developed by Palo Alto Research Center (PARC) in collaboration with Richards J. Heuer, Jr. It is a standard ACH program that allows analysts to enter evidence and rate its credibility and relevance.
+Decision Command software was developed by Willard Zangwill.
+DECIDE was developed by the analytic research firm SSS Research, Inc. DECIDE not only allows analysts to manipulate ACH, but it provides multiple visualization products.
+Analysis of Competing Hypotheses (ACH) is an open-source ACH implementation.
+ACH Template is an Excel sheet that implements the scoring and weighting methodology of ACH, more specifically the weighted inconsistency counting algorithm.
+
+== See also ==
+
+== Notes ==

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+title: "Anchoring effect"
+chunk: 1/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+The anchoring effect is a psychological phenomenon in which an individual's judgments or decisions are influenced by a reference point or "anchor" which can be completely irrelevant.
+The original description of the anchoring effect came from psychophysics. When judging stimuli along a continuum, it was noticed that the first and last stimuli were used to compare the other stimuli (this is also referred to as "end anchoring"). This concept was notably formalized in behavioral economics by Amos Tversky and Daniel Kahneman. In their seminal 1974 work, they described anchoring as a heuristic used to make estimates under uncertainty.
+Both numeric and non-numeric anchoring have been reported through research. In numeric anchoring, once the value of the anchor is set, subsequent arguments, estimates, etc. made by an individual may change from what they would have otherwise been without the anchor. For example, an individual may be more likely to purchase a car if it is placed alongside a more expensive model (the anchor).  Non-numeric anchoring has been observed in physical judgments involving length, weight, and volume.
+
+== Experimental findings ==
+
+The anchoring and adjustment heuristic was first theorized by Amos Tversky and Daniel Kahneman. In one of their first studies, participants were separated into one of two conditions, and either asked to compute, within 5 seconds, the product of the numbers one through to eight, either as 1 × 2 × 3 × 4 × 5 × 6 × 7 × 8 or reversed as 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1. Because participants did not have enough time to calculate the full answer, they had to make an estimate after their first few multiplications. When these first multiplications gave a small answer – because the sequence started with small numbers – the median estimate was 512; when the sequence started with the larger numbers, the median estimate was 2,250. (The correct answer is 40,320.) In another study by Tversky and Kahneman, participants were asked to estimate the percentage of African countries in the United Nations. Before estimating, the participants first observed a roulette wheel that was predetermined to stop on either 10 or 65. Participants whose wheel stopped on 10 guessed lower values (25% on average) than participants whose wheel stopped at 65 (45% on average). The pattern has held in other experiments for a wide variety of different subjects of estimation.
+As a second example, in a study by Dan Ariely, an audience is first asked to write the last two digits of their social security number and consider whether they would pay this number of dollars for items whose value they did not know, such as wine, chocolate and computer equipment. They were then asked to bid for these items, with the result that the audience members with higher two-digit numbers would submit bids that were between 60 percent and 120 percent higher than those with the lower social security numbers, which had become their anchor. When asked if they believed the number was informative of the value of the item, quite a few said yes. Trying to avoid this confusion, a small number of studies used procedures that were clearly random, such as Excel random generator button and die roll, and failed to replicate anchoring effects.
+The anchoring effect has also been documented in real estate markets. In one study in the Journal of Real Estate Research, it was established that the 2-year and 9-year highs on the Case-Shiller House Price Index could be used as anchors in predicting current house prices. The findings were used to indicate that, in forecasting house prices, these 2-year and 9-years highs might be relevant.
+In behavioral finance, anchoring has been observed in stock-purchase decisions. A study found that when using an app-based stock brokerage, an investor's first stock purchase price serves as an anchor for future stock purchases. The findings indicate that when investors start by making only a small stock purchase, they end up with less accumulated investments in the long run.
+
+== Characteristics ==
+
+=== Difficulty of avoiding ===
+Various studies have shown that anchoring is very difficult to avoid. For example, in one study students were given anchors that were wrong. They were asked whether Mahatma Gandhi died before or after age 9, or before or after age 140. Clearly neither of these anchors can be correct, but when the two groups were asked to suggest when they thought he had died, they guessed significantly differently (average age of 50 vs. average age of 67).
+Other studies have tried to eliminate anchoring much more directly. In a study exploring the causes and properties of anchoring, participants were exposed to an anchor and asked to guess how many physicians were listed in the local phone book. In addition, they were explicitly informed that anchoring would "contaminate" their responses, and that they should do their best to correct for that. A control group received no anchor and no explanation. Regardless of how they were informed and whether they were informed correctly, all of the experimental groups reported higher estimates than the control group. Thus, despite being expressly aware of the anchoring effect, most participants were still unable to avoid it. A later study found that even when offered monetary incentives, most people are unable to effectively adjust from an anchor.
+Although it has been found through many research and experiments that attempt to mitigate the decision heuristic of anchoring bias is either marginally significant or not successful at all, it can be found that the consider-the-opposite (COS strategy) has been the most reliable in mitigating the anchoring bias. In short, the COS strategy is proposed to an individual by asking them to consider the possibilities the opposite of their perceptions and beliefs. Therefore, depriving the individual of their preexisting attitudes and limiting the decision bias.

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+title: "Anchoring effect"
+chunk: 2/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+=== Durability of anchoring ===
+Anchoring effects are also shown to remain adequately present given the accessibility of knowledge pertaining to the target. This, in turn, suggests that despite a delay in judgement towards a target, the extent of anchoring effects have seen to remain unmitigated within a given time period. A series of three experiments were conducted to test the longevity of anchoring effects. It was observed that despite a delay of one week being introduced for half the sample population of each experiment, similar results of immediate judgement and delayed judgement of the target were achieved.  The experiments concluded that external information experienced within the delayed judgement period shows little influence relative to self-generated anchors even with commonly encountered targets (temperature) used in one of the experiments, showing that anchoring effects may precede priming in duration especially when the anchoring effects were formed during the task. Further research to conclude an effect that is effectively retained over a substantial period of time has proven inconsistent.
+
+=== Pervasiveness across contexts ===
+One notable characteristic of the anchoring effect is its pervasiveness across diverse judgment scenarios. Furnham and Boo (2011) highlight that anchoring occurs not only in abstract estimation tasks (like guessing the height of Mount Everest) but also in real-world contexts such as legal sentencing, consumer purchasing, salary negotiations, and forecasting. Anchoring persists even when the anchor is implausible or clearly irrelevant (e.g., spinning a random wheel), demonstrating that anchoring can operate automatically, outside of conscious awareness or logical evaluation.
+
+=== Anchoring bias in groups ===
+It is often presumed that groups come to a more unbiased decision relative to individuals. However, this assumption is supported with varied findings that could not come to a general consensus. Nevertheless, while some groups are able to perform better than an individual member, they are found to be just as biased or even more biased relative to their individual counterparts. A possible cause would be the discriminatory fashion in which information is communicated, processed and aggregated based on each individual's anchored knowledge and belief. This results in a diminished quality in the decision-making process and consequently, amplifies the pre-existing anchored biases.
+The cause of group anchoring remains unsure. Group anchors may have been established at the group level or may simply be the culmination of several individual's personal anchors. Prior studies have shown that when given an anchor before the experiment, individual members consolidated the respective anchors to attain a decision in the direction of the anchor placed. However, a distinction between individual and group-based anchor biases does exist, with groups tending to ignore or disregard external information due to the confidence in the joint decision-making process. The presence of pre-anchor preferences also impeded the extent to which external anchors affected the group decision, as groups tend to allocate more weight to self-generated anchors, according to the 'competing anchor hypothesis'.
+Recently, it has been suggested that the group member who speaks first often has an unproportionally high impact on the final decision. A series of experiments were conducted to investigate anchoring bias in groups and possible solutions to avoid or mitigate anchoring. The first experiment established that groups are indeed influenced by anchors while the other two experiments highlighted methods to overcome group anchoring bias. Methods that were utilized include the use of process accountability and motivation through competition instead of cooperation to reduce the influence of anchors within groups.
+
+=== Susceptibility in automated systems ===
+Even advanced technologies cannot prevent users from being influenced by anchoring. A peer-reviewed study sought to investigate the effect of business intelligence (BI) systems on the anchoring effect. Business intelligence denotes an array of software and services used by businesses to gather valuable insights into an organisation's performance. The extent to which cognitive bias is mitigated by using such systems was the overarching question in this study. While the independent variable was the use of the BI system, the dependent variable was the outcome of the decision-making process. The subjects were presented with a 'plausible' anchor and a 'spurious' anchor in a forecasting decision. It was found that, while the BI system mitigated the negative effects of the spurious anchor, it had no influence on the effects of the plausible anchor. This is important in a business context, because it shows that humans are still susceptible to cognitive biases, even when using sophisticated technological systems. One of the subsequent recommendations from the experimenters was to implement a forewarning into BI systems as to the anchoring effect.
+
+== Causes ==
+The present literature does not reach a consensus as to the cause of anchoring. However, scholars agree that anchoring is a phenomenon that can be easily demonstrated but is hard to explain. Some scholars suggest that anchoring is, in fact, caused by a combination of factors.

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+title: "Anchoring effect"
+chunk: 3/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+=== Anchoring-and-adjusting ===
+The most prevalent explanation of the anchoring effect is the argument originally made by Tversky and Kahneman, termed anchoring-and-adjusting. Based on this theory, individuals set an anchor according to available information, whether it is provided or individuals already have an anchor in mind, and use this anchor as a point of reference to adjust their answers. This theory explains inaccuracy in guessing by suggesting that people adjust insufficiently, rendering their final guess closer to the anchors. This phenomenon was further investigated in other studies and used as an explanation for biases such as hindsight bias and egocentric bias.
+For instance, when asked to guess the price of a drink in a coffee shop, individuals often look for the price of other drinks or recall the price of similar drinks at other stores, and base their answer on the anchor that they set. Specifically, the original study found that by simply providing an arbitrary anchor to each group, people provided significantly different responses, suggesting that their answers were generated through anchoring and adjusting. In addition, this finding suggests that individuals are gullible when setting an anchor, and almost automatically begin the anchoring-and-adjusting process.
+On the other hand, Epley and Gilovich found that when anchors are self-generated, people will stop adjusting once they believe they have adjusted their answers to an acceptable range. Although this process does not guarantee insufficient adjustments, it does result in an answer that is as close to the anchor as possible in the acceptable range. However, insufficient adjustments are diminished when individuals are able and motivated by external factors, such as monetary compensation, to continue adjusting for a more accurate answer, thereby reducing the anchoring effect. The anchoring effect is also reduced when individuals know which way to adjust from the anchor because it eliminates the possible answers by half.
+Besides general knowledge, anchoring is also observed in social settings. The simulation theory of empathy suggests that people use their own mental state and reasoning to infer the actions of others. People assume that those who are similar to us will act in a similar way. Aligned with this idea, Tamir and Mitchell found that judgments of the attitude of others are made more quickly for those who are similar to the judge, and greater self-other discrepancy resulted in longer reaction time. In this case, individuals use their own attitudes as an anchor and make adjustments to predict the attitude of others. Note that this process only takes place when the judge perceives great similarity between self and others.
+Overall, this theory describes the process of anchoring and adjusting away from the anchor, as well as the phenomenon of inaccurate responses due to insufficient adjusting. However, proponents of alternative theories argued that adjusting is only possible when the original anchor lies outside the acceptable range. According to Epley and Gilovich, individuals will not adjust at all and give an answer that is identical to their anchor if the anchor is already within the acceptable range. Using the previous example, the actual price of the drink can be identical to other drinks served at that store, meaning that people should theoretically consider their anchor as a potential answer rather than adjusting. When a reasonable anchor is given, there will be no adjustment. Therefore, this theory does not explain all cases of anchoring.
+
+=== Selective accessibility ===
+An alternative explanation of the anchoring effect is the idea that the accessibility of anchor-consistent information is enhanced when individuals consider it as a potential answer. After determining that the initial anchor is not the correct answer, they move on to consider other possibilities. However, because the anchor was just made salient and accessible to them, they will take the anchor into consideration while evaluating other possibilities. As a result, this comparative assessment can result in answers that are disproportionally consistent with the anchor. In this sense, anchoring is a special case of semantic priming, where the anchor acts as the prime.
+Unlike anchoring-and-adjusting, this theory suggests that people consider the relevant attributes of the initial anchor to determine if the anchor is plausible. Rather than accepting any plausible anchor as their answer and insufficiently adjusting anchors outside of the acceptable range, people will remain motivated to find a more accurate answer after rejecting the initial anchor. The preceding adjustments that individuals make are relevant to the anchor because people evaluate hypotheses through attempting to confirm them. In line with this idea, when investigating whether the plausibility of an anchor affects comparative and absolute judgments, Strack and Mussweiler found that individuals take longer to provide an absolute judgment when the anchor is implausible. Comparative judgments refer to the process of using an anchor to determine the final answer. Most paradigms used in anchoring studies also ask participants to provide an absolute judgment (i.e., provide a concrete number as their answer) after comparative judgments. When plausible anchors were used in comparative judgments, the anchor became more accessible, shortening the response time for consequent absolute judgments. In contrast, implausible anchors result in longer response time because there is no relevant information that can be used as primes.
+Although selective accessibility and anchoring-and-adjusting provide conflicting explanations for the anchoring effect, some scholars have argued that anchoring is influenced by multiple factors, and these theories complement each other in explaining the anchoring effect. For instance, Simmons and colleagues proposed an integrative theory suggesting that an anchor can result in selective reliance on anchor-consistent information, rendering the range of plausible answers closer to the anchor. On the other hand, people adjust away from (or possibly back toward) anchors before settling on their final estimate. This integrative theory is more parsimonious because it suggests that neither the source of the anchor (self-generated or provided) nor the plausibility of the anchor has a significant effect on judgments.

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+title: "Anchoring effect"
+chunk: 4/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+=== Attitude change ===
+On the contrary of the two previous theories, the attitude change view suggests that individuals' attitude towards an anchor, specifically provided anchors, can heavily affect the extent of the anchoring effect. Recall that individuals often seek to confirm their hypothesis rather than objectively evaluating all information. When individuals disagree with the provided anchor, they will selectively seek evidence that supports their own attitudes instead of the provided anchor, resulting in an unobserved anchoring effect. This theory highlights the idea that the distinct anchoring effect observed with self-generated and provided anchors roots from individual attitude (i.e., does the individual believe in the anchor) rather than the anchors themselves, supporting the integrative theory proposed by Simmons and colleagues. Furthermore, supporters of this view have argued that attitude change is an alternative explanation of the anchoring effect. Providing an anchor generates favorable attitudes in individuals toward the anchor, biasing consequent judgments.
+
+=== Extremeness aversion ===
+Extremeness aversion is a robust phenomenon where people try to avoid the extremes during decision-making, such as selecting the middle options more often than other extreme options and avoiding reporting the maximum or minimum on a Likert scale. This desire to avoid extremes is at least partially responsible for the anchoring effect. For instance, upon setting an anchor, participants who were told they could adjust up to 6 units made significantly smaller adjustments compared to those who were told that they could adjust up to 15 units, suggesting that people avoid extremes when making decisions. Importantly, the maximum allowable adjustment  acted as an anchor that affected the final judgment, highlighting the prevalent aversion to extremes. As a result, the final judgment is close to the anchor because people do not want to adjust too close to the extremes.
+
+=== Neuroscience basis ===
+Some research has explored neural mechanisms underlying the anchoring effect. Studies of individual differences report that mixed-handed individuals show larger anchoring effects than strongly handed individuals, a pattern consistent with differences in interhemispheric interaction. Electrophysiological work provides additional evidence: EEG studies suggest that externally presented anchors function as semantic primes that shape the cognitive and affective context in which judgments are formed. Higher anchors are associated with increased P2 and late positive potential (LPP) amplitudes, indicating greater anticipatory attention and expectations of stronger or more aversive outcomes. Research using EEG and fMRI in management-related judgment tasks further shows that anchor values engage distinct semantic and evaluative networks. Higher anchors produce stronger EEG power in value-judgment stages, and fMRI experiments reveal different reaction-time profiles and neural activation patterns for feasible, infeasible, and no-anchor conditions during both comparison and decision phases.
+
+== Influencing factors ==
+
+=== Cognitive ability ===
+The impact of cognitive ability on anchoring is contested. Predrag Teovanović's  investigated whether intelligence, cognitive reflection and personality traits affects the presence of anchoring effect in decision-making. Although measures of individual differences in susceptibility to anchoring were reliable, individual differences only explain a small portion of the variation. However, intelligence is negatively correlated with anchoring for participants who are more reflective. By critically thinking about their process of decision-making, reflective individuals might realize the unreasonable reliance on anchors and insufficient adjustments. Similarly, Welsh and colleagues found a weak, negative correlation between aptitude for rationality and overall cognitive measures and anchoring susceptibility. A study on willingness to pay for consumer goods found that anchoring decreased in those with greater cognitive ability, though it did not disappear. Research supporting individual differences in anchoring suggests that individuals who recognize the potential bias of anchoring and actively reflect on their decision-making process tend to be less susceptible to its effects. By critically assessing whether their judgments are based on reliable data or influenced by arbitrary anchors, they are more likely to identify and correct for insufficient adjustments, or choose not to use unreliable anchors at all.
+Another study, however, found that cognitive ability had no significant effect on how likely people were to use anchoring. In a poker-like experiment that included people of differing academic achievement and psychometric reasoning scoring, it has been found that anchoring is not related to education level. It also found that numerical reasoning and reflection scores had a negative association with anchoring susceptibility.
+
+=== Overconfidence ===
+Overconfidence is significantly associated with the anchoring effect. It refers specifically to the tendency for individuals to place excessive weight on their initial estimates and insufficient weight on new information leading to cognitive conceit. Cognitive conceit or overconfidence arises from other factors like personal cognitive attributes such as knowledge and decision-making ability, decreasing the probability to pursue external sources of confirmation. This factor has also been shown to arise with tasks with greater difficulty. Even within subject matter experts, they were also prey to such behaviour of overconfidence and should more so, actively reduce such behaviour. Following the study of estimations under uncertain, despite several attempts to curb overconfidence proving unsuccessful, Tversky and Kahneman suggest an effective solution to overconfidence is for subjects to explicitly establish anchors to help reduce overconfidence in their estimates.
+
+=== Personality ===
+
+Correlational research on anchoring bias and personality traits yielded mixed results, with emphasis on the Big Five personality traits which includes: Conscientiousness (orderly and responsible), neuroticism (uneasy and anxious), extraversion (sociable and outgoing), openness (intelligence and creativity) and agreeableness (polite and trusting). One study found that participants who were high in the Openness trait were more influenced by anchors set by others when estimating the length of the Mississippi river, with no other personality traits correlating to the effects of anchoring. Other research showed that it was conscientiousness and agreeableness that increased anchoring biases, while anchoring effects were diminished in participants high in the extraversion trait. Nonetheless, when measuring the Big Five personality traits and anchoring susceptibility, no significant correlation was found between personality and anchoring. The anchoring effect seems to be present regardless of personality.

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+title: "Anchoring effect"
+chunk: 5/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+=== Personal experience ===
+Early research found that experts (those with high knowledge, experience, or expertise in some field) were more resistant to the anchoring effect. However, anchoring happens unconsciously which means that unless someone who is knowledgeable is warned prior, they are still susceptible to anchoring. Since then, however, numerous studies have demonstrated that while experience can sometimes reduce the effect, even experts are susceptible to anchoring. In a study concerning the effects of anchoring on judicial decisions, researchers found that even experienced legal professionals were affected by anchoring. This remained true even when the anchors provided were arbitrary and unrelated to the case in question. Also, this relates to goal setting, where more experienced individuals will set goals based on their past experiences which consequently affects end results in negotiations.
+Expertise is typically defined as domain-specific knowledge and experience. In a study using price estimation of cars, it was found that relevant knowledge positively influenced anchoring. Expertise in cognitive bias is related to experience however the two are not exclusively exhaustive. In a study using stock return estimates, it was found that expertise decreases behavioural bias significantly. It was found that other factors like cognitive ability and experience where there is no susceptibility to anchoring or a susceptibility as it increases, tend to become factors that decrease the effects of anchoring when they are an expert.
+
+=== Motivation/rewards ===
+The motivation to be accurate in one's judgements seem to have mixed effects on the strength of anchoring. On one hand, According to Wegener's attitude change theory, it was widely accepted that the prevalent effects of anchoring was due to the pathway of low-elaboration, non-thoughtful processes. The lack of reward or consequences results in the assumption that anchors are a reasonable hint to the correct answer without considering contextual differences, categorical differences, or even the relevance of the anchor. There is also evidence that the effects of anchoring is diminished when there is prior warning about the phenomenon of insufficient adjustment  and self-generated anchors.
+However, there is also conflicting evidence where increases in motivation does not correlate to a lowered rate of anchoring. There were no differences in the effects of anchoring when comparing participants who were offered monetary rewards for accurate answers to those who weren't. Moreover, findings by Wilson et al. (1996) concluded that incentives and forewarnings did not eliminate anchoring effects.
+This could be explained by high elaborative anchoring - When motivated to be accurate, participants engage in more cognitively demanding thought processes, searching for existing information, including prior experiences and established anchors. The high need for accuracy lead to more effortful thought processes, and putting a heavier emphasis on anchors since they are representations of prior knowledge in what we perceive as similar categories. Findings have demonstrated that both a high and low need to be accurate result in susceptibility to the influence of anchoring effects, even when one is motivated to explicitly avoid them.
+
+=== Mood ===
+A wide range of research has linked sad or depressed moods with more extensive and accurate evaluation of problems. As a result of this, earlier studies hypothesized that people with more depressed moods would tend to use anchoring less than those with happier moods. However, more recent studies have shown the opposite effect: sad people are more likely to use anchoring than people with happy or neutral mood. In a study focusing on medical practitioners, it was found that physicians that possess positive moods are less susceptible to anchoring bias, when compared to physicians with neutral moods. Researchers suggested that positive mood promotes more systematic information processing, which can reduce susceptibility to anchoring.
+
+=== Culture ===
+Culture has been identified as an influencing factor in susceptibility to the anchoring effect. Research distinguishes between the holistic thinking style, predominant in East and Southeast Asian cultures, and the analytic thinking style, common in Western cultures. A study comparing students from Poland and India found that while both groups were affected by anchoring, the degree of susceptibility varied significantly by cultural background. Polish students demonstrated lower susceptibility to anchoring compared to Indian students. Additionally, cultural differences in overconfidence were observed, with Indian students displaying a higher rate of overprecision compared to Polish students. This is explained by the differences in cultural difference in tolerances for ambiguity and risk (uncertainty avoidance), with Poland scoring high and India scoring medium to low on Hofstede's Uncertainty Avoidance Index (UAI).
+
+== Applications ==

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+---
+title: "Anchoring effect"
+chunk: 6/6
+source: "https://en.wikipedia.org/wiki/Anchoring_effect"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:19.378582+00:00"
+instance: "kb-cron"
+---
+
+=== Anchoring in negotiation ===
+In the negotiation process anchoring serves to determine an accepted starting point for the subsequent negotiations. As soon as one side states their first price offer, the (subjective) anchor is set. The counterbid (counter-anchor) is the second-anchor.
+In addition to the initial research conducted by Tversky and Kahneman, multiple other studies have shown that anchoring can greatly influence the estimated value of an object. For instance, although negotiators can generally appraise an offer based on multiple characteristics, studies have shown that they tend to focus on only one aspect. In this way, a deliberate starting point can strongly affect the range of possible counteroffers. The process of offer and counteroffer results in a mutually beneficial arrangement. However, multiple studies have shown that initial offers have a stronger influence on the outcome of negotiations than subsequent counteroffers.
+An example of the power of anchoring has been conducted during the Strategic Negotiation Process Workshops. During the workshop, a group of participants is divided into two sections: buyers and sellers. Each side receives identical information about the other party before going into a one-on-one negotiation. Following this exercise, both sides debrief about their experiences. The results show that where the participants anchor the negotiation had a significant effect on their success.
+Anchoring affects everyone, even people who are highly knowledgeable in a field. Northcraft and Neale conducted a study to measure the difference in the estimated value of a house between students and real-estate agents. In this experiment, both groups were shown a house and then given different listing prices. After making their offer, each group was then asked to discuss what factors influenced their decisions. In the follow-up interviews, the real-estate agents denied being influenced by the initial price, but the results showed that both groups were equally influenced by that anchor.
+Anchoring can have more subtle effects on negotiations as well. Janiszewski and Uy investigated the effects of precision of an anchor. Participants read an initial price for a beach house, then gave the price they thought it was worth. They received either a general, seemingly nonspecific anchor (e.g., $800,000) or a more precise and specific anchor (e.g., $799,800). Participants with a general anchor adjusted their estimate more than those given a precise anchor ($751,867 vs $784,671). The authors propose that this effect comes from difference in scale; in other words, the anchor affects not only the starting value, but also the starting scale. When given a general anchor of $20, people will adjust in large increments ($19, $21, etc.), but when given a more specific anchor like $19.85, people will adjust on a lower scale ($19.75, $19.95, etc.). Thus, a more specific initial price will tend to result in a final price closer to the initial one.
+As for the question of setting the first or second anchor, the party setting the second anchor has the advantage in that the counter-anchor determines the point midway between both anchors. Due to a possible lack of knowledge the party setting the first anchor can also set it too low, i.e. against their own interests. Generally negotiators who set the first anchor also tend to be less satisfied with the negotiation outcome, than negotiators who set the counter-anchor. This may be due to the regret or sense that they did not achieve or rather maximise the full potential of the negotiations. However, studies suggest that negotiators who set the first offer frequently achieve economically more advantageous results.
+
+=== Anchoring in pricing ===
+According to the theory, consumers' shopping experiences are influenced by factors such as time restriction and specific environment. Enterprises design would set anchor values for consumers in order to get them to buy the products. 
+When persuading consumers to purchase a particular product, sellers might use anchoring. Sellers often influence consumers' price perception by anchoring a high reference price and that is an anchor value. Following are three ways to set the anchor value for consumers.
+
+==== Sorting the prices of products ====
+Sellers usually sort the prices of products from high to low and this method is commonly seen on the menus of restaurants. The high prices at the top of the menu act as anchor values in this situation. Consumers will have an expectation that the products are all expensive when knowing the relatively high prices of products on the top of the list. As a result, they will be pleased to see the cheaper products at the middle and bottom of the list and regard these prices as acceptable or cheaper than expected. Therefore, they are more likely to buy these products.
+
+==== Decoy ====
+Decoy effect is defined as a situation where people tend to have a change in preference between two choices when they are showed with a third choice. The third choice is called a decoy which is designed to induce consumers to change their preferences. The decoy is usually considered as inferior. For example, it might be more expensive than option A while having lower quality than option B. In this case, the anchor is the decoy.
+One decoy effect example is the bundle sales. For example, many restaurants often sell set meals to their consumers, while simultaneously having the meals' components sold separately. The prices of the meals' components are the decoy pricing and act as an anchor which enables to make the set meal more valuable to consumers. With the decoy effect it generates, the anchor increases consumers' willingness to pay for the set meals, or the mixed bundles.
+
+==== Incidental prices ====
+Incidental price is defined as the prices offered or showed by a seller for products which the consumers are not interested in. According to the theory, the incidental price serves as an anchor which increases consumers' willingness to pay. This effect has been widely used in areas such as auctions, online vendors and retailers.
+
+== See also ==
+
+Bandwagon effect
+Confirmation bias
+Framing effect
+Law of the instrument
+List of cognitive biases
+Matthew effect
+Negotiation strategies
+Poisoning the well
+Primacy effect
+
+== References ==
+
+== External links ==
+Serfas, S. (2010). Cognitive Biases in the Capital Investment Context: Theoretical Considerations and Empirical Experiments on Violations of Normative Rationality. Gabler research. Gabler Verlag. pp. 67–70. ISBN 978-3-8349-6485-4. Retrieved April 9, 2019.
+"Price Anchoring Demonstration". Gary's Class. Retrieved 2 April 2026.

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+---
+title: "Anfinsen's dogma"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Anfinsen's_dogma"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:00.330938+00:00"
+instance: "kb-cron"
+---
+
+Anfinsen's dogma, also known as the thermodynamic hypothesis, is a postulate in molecular biology. It states that, at least for a small globular protein in its standard physiological environment, the native structure is determined only by the protein's amino acid sequence. The dogma was championed by the Nobel Prize Laureate Christian B. Anfinsen from his research on the folding of ribonuclease A. His research was based on previous studies by biochemist Lisa Steiner, whose superiors at the time did not recognize the significance. The postulate amounts to saying that, at the environmental conditions (temperature, solvent concentration and composition, etc.) at which folding occurs, the native structure is a unique, stable and kinetically accessible minimum of the free energy. In other words, there are three conditions for formation of a unique protein structure:
+
+Uniqueness – Requires that the sequence does not have any other configuration with a comparable free energy. Hence the free energy minimum must be unchallenged.
+
+Stability – Small changes in the surrounding environment cannot give rise to changes in the minimum configuration. This can be pictured as a free energy surface that looks more like a funnel (with the native state in the bottom of it) rather than like a soup plate (with several closely related low-energy states); the free energy surface around the native state must be rather steep and high, in order to provide stability.
+
+Kinetical accessibility – Means that the path in the free energy surface from the unfolded to the folded state must be reasonably smooth or, in other words, that the folding of the chain must not involve highly complex changes in the shape (like knots or other high order conformations). Basic changes in the shape of the protein happen dependent on their environment, shifting shape to suit their place. This creates multiple configurations for biomolecules to shift into.
+
+
+== Challenges to Anfinsen's dogma ==
+Protein folding in a cell is a highly complex process that involves transport of the newly synthesized proteins to appropriate cellular compartments through targeting, permanent misfolding, temporarily unfolded states, post-translational modifications, quality control, and formation of protein complexes facilitated by chaperones.   
+Some proteins need the assistance of chaperone proteins to fold properly. It has been suggested that this disproves Anfinsen's dogma. However, the chaperones do not appear to affect the final state of the protein; they seem to work primarily by preventing aggregation of several protein molecules prior to the final folded state of the protein. However, at least some chaperones are required for the proper folding of their subject proteins.
+Many proteins can also undergo aggregation and misfolding. For example, prions are stable conformations of proteins which differ from the native folding state. In bovine spongiform encephalopathy, native proteins re-fold into a different stable conformation, which causes fatal amyloid buildup. Other amyloid diseases, including Alzheimer's disease and Parkinson's disease, are also exceptions to Anfinsen's dogma.
+Some proteins have multiple native structures, and change their fold based on some external factors. For example, the KaiB protein complex switches fold throughout the day, acting as a clock for cyanobacteria. It has been estimated that around 0.5–4% of Protein Data Bank (PDB) proteins switch folds. The switching between alternative structures is driven by interactions of the protein with small ligands or other proteins, by chemical modifications (such as phosphorylation) or by changed environmental conditions, such as temperature, pH or membrane potential. Each alternative structure may either correspond to the global minimum of free energy of the protein at the given conditions or be kinetically trapped in a higher local minimum of free energy.
+
+
+== References ==
+
+
+== Further reading ==
+Sela M, White FH Jr, Anfinsen CB (1957). "Reductive cleavage of disulfide bridges in ribonuclease". Science. 125 (3250): 691–692. Bibcode:1957Sci...125..691S. doi:10.1126/science.125.3250.691. PMID 13421663. S2CID 36895461.
+Anfinsen CB, Haber E (1961). "Studies on the reduction and re-formation of protein disulfide bonds". J. Biol. Chem. 236 (5): 1361–1363. doi:10.1016/S0021-9258(18)64177-8. PMID 13683523.
+Moore S, Stein WH (1973). "Chemical structures of pancreatic ribonuclease and deoxyribonuclease". Science. 180 (4085): 458–464. Bibcode:1973Sci...180..458M. doi:10.1126/science.180.4085.458. PMID 4573392.
+Profiles in Science: The Christian B. Anfinsen Papers-Articles

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+title: "Animal testing"
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+category: "reference"
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+---
+
+Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals, as model organisms, in experiments that seek answers to scientific and medical questions. This approach can be contrasted with field studies in which animals are observed in their natural environments or habitats. Experimental research with animals is usually conducted in universities, medical schools, pharmaceutical companies, defense establishments, and commercial facilities that provide animal-testing services to the industry. The focus of animal testing varies on a continuum from pure research, focusing on developing fundamental knowledge of an organism, to applied research, which may focus on answering some questions of great practical importance, such as finding a cure for a disease. Examples of applied research include testing disease treatments, breeding, defense research, and toxicology, including cosmetics testing. In education, animal testing is sometimes a component of biology or psychology courses.
+Research using animal models has been central to most of the achievements of modern medicine. It has contributed to most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. The results have included the near-eradication of polio and the development of organ transplantation, and have benefited both humans and animals. From 1910 to 1927, Thomas Hunt Morgan's work with the fruit fly Drosophila melanogaster identified chromosomes as the vector of inheritance for genes, and Eric Kandel wrote that Morgan's discoveries "helped transform biology into an experimental science". Research in model organisms led to further medical advances, such as the production of the diphtheria antitoxin and the 1922 discovery of insulin and its use in treating diabetes, which was previously fatal. Modern general anaesthetics such as halothane were also developed through studies on model organisms, and are necessary for modern, complex surgical operations. Other 20th-century medical advances and treatments that relied on research performed in animals include organ transplant techniques, the heart-lung machine, antibiotics, and the whooping cough vaccine.
+Animal testing is widely used to aid in research of human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution. Performing experiments in model organisms allows for better understanding of the disease process without the added risk of harming an actual human. The species of the model organism is usually chosen so that it reacts to disease or its treatment in a way that resembles human physiology as needed. Biological activity in a model organism does not ensure an effect in humans, and care must be taken when generalizing from one organism to another. However, many drugs, treatments and cures for human diseases are developed in part with the guidance of animal models. Treatments for animal diseases have also been developed, including for rabies, anthrax, glanders, feline immunodeficiency virus (FIV), tuberculosis, Texas cattle fever, classical swine fever (hog cholera), heartworm, and other parasitic infections. Animal experimentation continues to be required for biomedical research, and is used with the aim of solving medical problems such as Alzheimer's disease, AIDS, multiple sclerosis, spinal cord injury, and other conditions in which there is no useful in vitro model system available.
+The annual use of vertebrate animals—from zebrafish to non-human primates—was estimated at 192 million as of 2015. In the European Union, vertebrate species represent 93% of animals used in research, and 11.5 million animals were used there in 2011. The mouse (Mus musculus) is associated with many important biological discoveries of the 20th and 21st centuries, and by one estimate, the number of mice and rats used in the United States alone in 2001 was 80 million. In 2013, it was reported that mammals (mice and rats), fish, amphibians, and reptiles together accounted for over 85% of research animals. In 2022, a law was passed in the United States that eliminated the FDA requirement that all drugs be tested on animals.
+Animal testing is regulated to varying degrees in different countries. In some cases it is strictly controlled while others have more relaxed regulations. There are ongoing debates about the ethics and necessity of animal testing. Proponents argue that it has led to significant advancements in medicine and other fields while opponents raise concerns about cruelty towards animals and question its effectiveness and reliability. There are efforts underway to find alternatives to animal testing such as computer simulation models, organs-on-chips technology that mimics human organs for lab tests, microdosing techniques which involve administering small doses of test compounds to human volunteers instead of non-human animals for safety tests or drug screenings, positron emission tomography (PET) scans which allow scanning of the human brain without harming humans, comparative epidemiological studies among human populations, and simulators and computer programs for teaching purposes.
+
+== Definitions ==
+The terms animal testing, animal experimentation, animal research, in vivo testing, and vivisection have similar denotations but different connotations. Literally, "vivisection" means "live sectioning" of an animal, and historically referred only to experiments that involved the dissection of live animals. The term is occasionally used to refer pejoratively to any experiment using living animals; for example, the Encyclopædia Britannica defines "vivisection" as: "Operation on a living animal for experimental rather than healing purposes; more broadly, all experimentation on live animals", although dictionaries point out that the broader definition is "used only by people who are opposed to such work". The word has a negative connotation, implying torture, suffering, and death. The word "vivisection" is preferred by those opposed to this research, whereas scientists typically use the term "animal experimentation".
+The following text excludes as much as possible practices related to in vivo veterinary surgery, which is left to the discussion of vivisection.
+
+== History ==

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+
+The earliest references to animal testing are found in the writings of the Greeks in the 2nd and 4th centuries BCE. Aristotle and Erasistratus were among the first to perform experiments on living animals. Galen, a 2nd-century Roman physician, performed post-mortem dissections of pigs and goats. Avenzoar, a 12th-century Arabic physician in Moorish Spain introduced an experimental method of testing surgical procedures before applying them to human patients. Discoveries in the 18th and 19th centuries included Antoine Lavoisier's use of a guinea pig in a calorimeter to prove that respiration was a form of combustion, and Louis Pasteur's demonstration of the germ theory of disease in the 1880s using anthrax in sheep. Robert Koch used animal testing of mice and guinea pigs to discover the bacteria that cause anthrax and tuberculosis. In the 1890s, Ivan Pavlov famously used dogs to describe classical conditioning.
+Research using animal models has been central to most of the achievements of modern medicine. It has contributed most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. For example, the results have included the near-eradication of polio and the development of organ transplantation, and have benefited both humans and animals. From 1910 to 1927, Thomas Hunt Morgan's work with the fruit fly Drosophila melanogaster identified chromosomes as the vector of inheritance for genes. Drosophila became one of the first, and for some time the most widely used, model organisms, and Eric Kandel wrote that Morgan's discoveries "helped transform biology into an experimental science". D. melanogaster remains one of the most widely used eukaryotic model organisms. During the same time period, studies on mouse genetics in the laboratory of William Ernest Castle in collaboration with Abbie Lathrop led to generation of the DBA ("dilute, brown and non-agouti") inbred mouse strain and the systematic generation of other inbred strains. The mouse has since been used extensively as a model organism and is associated with many important biological discoveries of the 20th and 21st centuries.
+In the late 19th century, Emil von Behring isolated the diphtheria toxin and demonstrated its effects in guinea pigs. He went on to develop an antitoxin against diphtheria in animals and then in humans, which resulted in the modern methods of immunization and largely ended diphtheria as a threatening disease. The diphtheria antitoxin is famously commemorated in the Iditarod race, which is modeled after the delivery of antitoxin in the 1925 serum run to Nome. The success of animal studies in producing the diphtheria antitoxin has also been attributed as a cause for the decline of the early 20th-century opposition to animal research in the United States.
+Subsequent research in model organisms led to further medical advances, such as Frederick Banting's research in dogs, which determined that the isolates of pancreatic secretion could be used to treat dogs with diabetes. This led to the 1922 discovery of insulin (with John Macleod) and its use in treating diabetes, which had previously meant death. John Cade's research in guinea pigs discovered the anticonvulsant properties of lithium salts, which revolutionized the treatment of bipolar disorder, replacing the previous treatments of lobotomy or electroconvulsive therapy. Modern general anaesthetics, such as halothane and related compounds, were also developed through studies on model organisms, and are necessary for modern, complex surgical operations.
+In the 1940s, Jonas Salk used rhesus monkey studies to isolate the most virulent forms of the polio virus, which led to his invention of the polio vaccine. The vaccine, which was made publicly available in 1955, reduced the incidence of polio 15-fold in the United States over the following five years. Albert Sabin improved the vaccine by passing the polio virus through animal hosts, including monkeys; the Sabin vaccine was produced for mass consumption in 1963, and had virtually eradicated polio in the United States by 1965. It has been estimated that developing and producing the vaccines required the use of 100,000 rhesus monkeys, with 65 doses of vaccine produced from each monkey. Sabin wrote in 1992, "Without the use of animals and human beings, it would have been impossible to acquire the important knowledge needed to prevent much suffering and premature death not only among humans, but also among animals."
+On 3 November 1957, a Soviet dog, Laika, became the first of many animals to orbit the Earth. In the 1970s, antibiotic treatments and vaccines for leprosy were developed using armadillos, then given to humans. The ability of humans to change the genetics of animals took an enormous step forward in 1974 when Rudolf Jaenisch could produce the first transgenic mammal, by integrating DNA from simians into the genome of mice. This genetic research progressed rapidly and, in 1996, Dolly the sheep was born, the first mammal to be cloned from an adult cell.
+Other 20th-century medical advances and treatments that relied on research performed in animals include organ transplant techniques, the heart-lung machine, antibiotics, and the whooping cough vaccine. Treatments for animal diseases have also been developed, including for rabies, anthrax, glanders, feline immunodeficiency virus (FIV), tuberculosis, Texas cattle fever, classical swine fever (hog cholera), heartworm, and other parasitic infections. Animal experimentation continues to be required for biomedical research, and is used with the aim of solving medical problems such as Alzheimer's disease, AIDS, multiple sclerosis, spinal cord injury, many headaches, and other conditions in which there is no useful in vitro model system available.
+Toxicology testing became important in the 20th century. In the 19th century, laws regulating drugs were more relaxed. For example, in the U.S., the government could only ban a drug after they had prosecuted a company for selling products that harmed customers. However, in response to the Elixir Sulfanilamide disaster of 1937 in which the eponymous drug killed over 100 users, the US Congress passed laws that required safety testing of drugs on animals before they could be marketed. Other countries enacted similar legislation. In the 1960s, in reaction to the Thalidomide tragedy, further laws were passed requiring safety testing on pregnant animals before a drug can be sold.

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+title: "Animal testing"
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+category: "reference"
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+
+metabolic tests, investigating pharmacokinetics—how drugs are absorbed, metabolized and excreted by the body when introduced orally, intravenously, intraperitoneally, intramuscularly, or transdermally.
+toxicology tests, which gauge acute, sub-acute, and chronic toxicity. Acute toxicity is studied by using a rising dose until signs of toxicity become apparent. Current European legislation demands that "acute toxicity tests must be carried out in two or more mammalian species" covering "at least two different routes of administration". Sub-acute toxicity is where the drug is given to the animals for four to six weeks in doses below the level at which it causes rapid poisoning, in order to discover if any toxic drug metabolites build up over time. Testing for chronic toxicity can last up to two years and, in the European Union, is required to involve two species of mammals, one of which must be non-rodent.
+efficacy studies, which test whether experimental drugs work by inducing the appropriate illness in animals. The drug is then administered in a double-blind controlled trial, which allows researchers to determine the effect of the drug and the dose-response curve.
+Specific tests on reproductive function, embryonic toxicity, or carcinogenic potential can all be required by law, depending on the result of other studies and the type of drug being tested.
+
+=== Education ===
+It is estimated that 20 million animals are used annually for educational purposes in the United States including, classroom observational exercises, dissections and live-animal surgeries. Frogs, fetal pigs, perch, cats, earthworms, grasshoppers, crayfish and starfish are commonly used in classroom dissections. Alternatives to the use of animals in classroom dissections are widely used, with many U.S. States and school districts mandating students be offered the choice to not dissect. Citing the wide availability of alternatives and the decimation of local frog species, India banned dissections in 2014.
+The Sonoran Arthropod Institute hosts an annual Invertebrates in Education and Conservation Conference to discuss the use of invertebrates in education. There also are efforts in many countries to find alternatives to using animals in education. The NORINA database, maintained by Norecopa, lists products that may be used as alternatives or supplements to animal use in education, and in the training of personnel who work with animals. These include alternatives to dissection in schools. InterNICHE has a similar database and a loans system.
+In November 2013, the U.S.-based company Backyard Brains released for sale to the public what they call the "Roboroach", an "electronic backpack" that can be attached to cockroaches. The operator is required to amputate a cockroach's antennae, use sandpaper to wear down the shell, insert a wire into the thorax, and then glue the electrodes and circuit board onto the insect's back. A mobile phone app can then be used to control it via Bluetooth. It has been suggested that the use of such a device may be a teaching aid that can promote interest in science. The makers of the "Roboroach" have been funded by the National Institute of Mental Health and state that the device is intended to encourage children to become interested in neuroscience.
+
+=== Defense ===
+Animals are used by the military to develop weapons, vaccines, battlefield surgical techniques, and defensive clothing. For example, in 2008 the United States Defense Advanced Research Projects Agency used live pigs to study the effects of improvised explosive device explosions on internal organs, especially the brain.
+In the US military, goats are commonly used to train combat medics. (Goats have become the main animal species used for this purpose after the Pentagon phased out using dogs for medical training in the 1980s.) While modern mannequins used in medical training are quite efficient in simulating the behavior of a human body, some trainees feel that "the goat exercise provide[s] a sense of urgency that only real life trauma can provide". Nevertheless, in 2014, the U.S. Coast Guard announced that it would reduce the number of animals it uses in its training exercises by half after PETA released video showing Guard members cutting off the limbs of unconscious goats with tree trimmers and inflicting other injuries with a shotgun, pistol, ax and a scalpel. That same year, citing the availability of human simulators and other alternatives, the Department of Defense announced it would begin reducing the number of animals it uses in various training programs. In 2013, several Navy medical centers stopped using ferrets in intubation exercises after complaints from PETA.
+Besides the United States, six out of 28 NATO countries, including Poland and Denmark, use live animals for combat medic training.
+
+== Ethics ==
+Most animals are euthanized after being used in an experiment. Sources of laboratory animals vary between countries and species; most animals are purpose-bred, while a minority are caught in the wild or supplied by dealers who obtain them from auctions and pounds. Supporters of the use of animals in experiments, such as the British Royal Society, argue that virtually every medical achievement in the 20th century relied on the use of animals in some way. The Institute for Laboratory Animal Research of the United States National Academy of Sciences has argued that animal testing cannot be replaced by even sophisticated computer models, which are unable to deal with the extremely complex interactions between molecules, cells, tissues, organs, organisms and the environment. Animal rights organizations—such as PETA and BUAV—question the need for and legitimacy of animal testing, arguing that it is cruel and poorly regulated, that medical progress is actually held back by misleading animal models that cannot reliably predict effects in humans, that some of the tests are outdated, that the costs outweigh the benefits, or that animals have the intrinsic right not to be used or harmed in experimentation.
+
+=== Viewpoints ===

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+
+The moral and ethical questions raised by performing experiments on animals are subject to debate, and viewpoints have shifted significantly over the 20th century. There remain disagreements about which procedures are useful for which purposes, as well as disagreements over which ethical principles apply to which species.
+A 2015 Gallup poll found that 67% of Americans were "very concerned" or "somewhat concerned" about animals used in research. A Pew poll taken the same year found 50% of American adults opposed the use of animals in research.
+Still, a wide range of viewpoints exist. The view that animals have moral rights (animal rights) is a philosophical position proposed by Tom Regan, among others, who argues that animals are beings with beliefs and desires, and as such are the "subjects of a life" with moral value and therefore moral rights. Regan still sees ethical differences between killing human and non-human animals, and argues that to save the former it is permissible to kill the latter. Likewise, a "moral dilemma" view suggests that avoiding potential benefit to humans is unacceptable on similar grounds, and holds the issue to be a dilemma in balancing such harm to humans to the harm done to animals in research. In contrast, an abolitionist view in animal rights holds that there is no moral justification for any harmful research on animals that is not to the benefit of the individual animal. Bernard Rollin argues that benefits to human beings cannot outweigh animal suffering, and that human beings have no moral right to use an animal in ways that do not benefit that individual. Donald Watson has stated that vivisection and animal experimentation "is probably the cruelest of all Man's attack on the rest of Creation." Another prominent position is that of philosopher Peter Singer, who argues that there are no grounds to include a being's species in considerations of whether their suffering is important in utilitarian moral considerations. Malcolm Macleod and collaborators argue that most controlled animal studies do not employ randomization, allocation concealment, and blinding outcome assessment, and that failure to employ these features exaggerates the apparent benefit of drugs tested in animals, leading to a failure to translate much animal research for human benefit.
+Governments such as the Netherlands and New Zealand have responded to the public's concerns by outlawing invasive experiments on certain classes of non-human primates, particularly the great apes. In 2015, captive chimpanzees in the U.S. were added to the Endangered Species Act adding new road blocks to those wishing to experiment on them. Similarly, citing ethical considerations and the availability of alternative research methods, the U.S. NIH announced in 2013 that it would dramatically reduce and eventually phase out experiments on chimpanzees.
+The British government has required that the cost to animals in an experiment be weighed against the gain in knowledge. Some medical schools and agencies in China, Japan, and South Korea have built cenotaphs for killed animals. In Japan there are also annual memorial services Ireisai (Japanese: 慰霊祭) for animals sacrificed at medical school.
+
+Various specific cases of animal testing have drawn attention, including both instances of beneficial scientific research, and instances of alleged ethical violations by those performing the tests. The fundamental properties of muscle physiology were determined with work done using frog muscles (including the force generating mechanism of all muscle, the length-tension relationship, and the force-velocity curve), and frogs are still the preferred model organism due to the long survival of muscles in vitro and the possibility of isolating intact single-fiber preparations (not possible in other organisms). Modern physical therapy and the understanding and treatment of muscular disorders is based on this work and subsequent work in mice (often engineered to express disease states such as muscular dystrophy). In February 1997 a team at the Roslin Institute in Scotland announced the birth of Dolly the sheep, the first mammal to be cloned from an adult somatic cell.
+Concerns have been raised over the mistreatment of primates undergoing testing. In 1985, the case of Britches, a macaque monkey at the University of California, Riverside, gained public attention. He had his eyelids sewn shut and a sonar sensor on his head as part of an experiment to test sensory substitution devices for blind people. The laboratory was raided by Animal Liberation Front in 1985, removing Britches and 466 other animals. The National Institutes of Health conducted an eight-month investigation and concluded, however, that no corrective action was necessary. During the 2000s other cases have made headlines, including experiments at the University of Cambridge and Columbia University in 2002. In 2004 and 2005, undercover footage of staff of in an animal testing facility in Virginia owned by Covance (now Fortrea) was shot by People for the Ethical Treatment of Animals (PETA). Following release of the footage, the U.S. Department of Agriculture fined the company $8,720 for 16 citations, three of which involved lab monkeys; the other citations involved administrative issues and equipment.

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+
+=== Threats to researchers ===
+Threats of violence to animal researchers are not uncommon.
+In 2006, a primate researcher at the University of California, Los Angeles (UCLA) shut down the experiments in his lab after threats from animal rights activists. The researcher had received a grant to use 30 macaque monkeys for vision experiments; each monkey was anesthetized for a single physiological experiment lasting up to 120 hours, and then euthanized. The researcher's name, phone number, and address were posted on the website of the Primate Freedom Project. Demonstrations were held in front of his home. A Molotov cocktail was placed on the porch of what was believed to be the home of another UCLA primate researcher; instead, it was accidentally left on the porch of an elderly woman unrelated to the university. The Animal Liberation Front claimed responsibility for the attack. As a result of the campaign, the researcher sent an email to the Primate Freedom Project stating "you win", and "please don't bother my family anymore". In another incident at UCLA in June 2007, the Animal Liberation Brigade placed a bomb under the car of a UCLA children's ophthalmologist who experiments on cats and rhesus monkeys; the bomb had a faulty fuse and did not detonate.
+In 1997, PETA filmed staff from Huntingdon Life Sciences, showing dogs being mistreated. The employees responsible were dismissed, with two given community service orders and ordered to pay £250 costs, the first lab technicians to have been prosecuted for animal cruelty in the UK. The Stop Huntingdon Animal Cruelty campaign used tactics ranging from non-violent protest to the alleged firebombing of houses owned by executives associated with HLS's clients and investors. The Southern Poverty Law Center, which monitors US domestic extremism, has described SHAC's modus operandi as "frankly terroristic tactics similar to those of anti-abortion extremists", and in 2005 an official with the FBI's counter-terrorism division referred to SHAC's activities in the United States as domestic terrorist threats. 13 members of SHAC were jailed for between 15 months and eleven years on charges of conspiracy to blackmail or harm HLS and its suppliers.
+These attacks—as well as similar incidents that caused the Southern Poverty Law Center to declare in 2002 that the animal rights movement had "clearly taken a turn toward the more extreme"—prompted the US government to pass the Animal Enterprise Terrorism Act and the UK government to add the offense of "Intimidation of persons connected with animal research organisation" to the Serious Organised Crime and Police Act 2005. Such legislation and the arrest and imprisonment of activists may have decreased the incidence of attacks.
+
+=== Scientific criticism ===
+Systematic reviews have pointed out that animal testing often fails to accurately mirror outcomes in humans. For instance, a 2013 review noted that some 100 vaccines have been shown to prevent HIV in animals, yet none of them have worked on humans. Effects seen in animals may not be replicated in humans, and vice versa. Many corticosteroids cause birth defects in animals, but not in humans. Conversely, thalidomide causes serious birth defects in humans, but not in some animals such as mice (however, it does cause birth defects in rabbits). A 2004 paper concluded that much animal research is wasted because systemic reviews are not used, and due to poor methodology. A 2006 review found multiple studies where there were promising results for new drugs in animals, but human clinical studies did not show the same results. The researchers suggested that this might be due to researcher bias, or simply because animal models do not accurately reflect human biology. Lack of meta-reviews may be partially to blame. Poor methodology is an issue in many studies. A 2009 review noted that many animal experiments did not use blinded experiments, a key element of many scientific studies in which researchers are not told about the part of the study they are working on to reduce bias. A 2021 paper found, in a sample of Open Access Alzheimer Disease studies, that if the authors omitted from the title that the experiment was performed in mice, the news headline followed suit and the Twitter repercussion was higher.
+
+=== Activism ===
+
+There are various examples of activists utilizing Freedom of Information Act (FOIA) requests to obtain information about taxpayer funding of animal testing. For example, the White Coat Waste Project, a group of activists that hold that taxpayers should not have to pay $20 billion every year for experiments on animals, highlighted that the National Institute of Allergy and Infectious Diseases provided $400,000 in taxpayer money to fund experiments in which 28 beagles were infected by disease-causing parasites. The White Coat Project found reports that said dogs taking part in the experiments were "vocalizing in pain" after being injected with foreign substances. Following public outcry, People for the Ethical Treatment of Animals (PETA) made a call to action that all members of the National Institute of Health resign effective immediately and that there is a "need to find a new NIH director to replace the outgoing Francis Collins who will shut down research that violates the dignity of nonhuman animals."
+
+=== Historical debate ===

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+title: "Animal testing"
+chunk: 14/15
+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
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+---
+
+As the experimentation on animals increased, especially the practice of vivisection, so did criticism and controversy. In 1655, the advocate of Galenic physiology Edmund O'Meara said that "the miserable torture of vivisection places the body in an unnatural state". O'Meara and others argued pain could affect animal physiology during vivisection, rendering results unreliable. There were also objections ethically, contending that the benefit to humans did not justify the harm to animals. Early objections to animal testing also came from another angle—many people believed animals were inferior to humans and so different that results from animals could not be applied to humans.
+On the other side of the debate, those in favor of animal testing held that experiments on animals were necessary to advance medical and biological knowledge. Claude Bernard—who is sometimes known as the "prince of vivisectors" and the father of physiology, and whose wife, Marie Françoise Martin, founded the first anti-vivisection society in France in 1883—famously wrote in 1865 that "the science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen". Arguing that "experiments on animals [. . .] are entirely conclusive for the toxicology and hygiene of man [. . .] The effects of these substances are the same on man as on animals, save for differences in degree", Bernard established animal experimentation as part of the standard scientific method.
+In 1896, the physiologist and physician Dr. Walter B. Cannon said "The antivivisectionists are the second of the two types Theodore Roosevelt described when he said, 'Common sense without conscience may lead to crime, but conscience without common sense may lead to folly, which is the handmaiden of crime.'" These divisions between pro- and anti-animal testing groups first came to public attention during the Brown Dog affair in the early 1900s, when hundreds of medical students clashed with anti-vivisectionists and police over a memorial to a vivisected dog.
+In 1822, the first animal protection law was enacted in the British parliament, followed by the Cruelty to Animals Act (1876), the first law specifically aimed at regulating animal testing. The legislation was promoted by Charles Darwin, who wrote to Ray Lankester in March 1871: "You ask about my opinion on vivisection. I quite agree that it is justifiable for proper investigations on physiology; but not for mere damnable and detestable curiosity. It is a subject which makes me sick with horror, so I will not say another word about it, else I shall not sleep to-night." In response to the lobbying by anti-vivisectionists, several organizations were set up in Britain to defend animal research: The Physiological Society was formed in 1876 to give physiologists "mutual benefit and protection", the Association for the Advancement of Medicine by Research was formed in 1882 and focused on policy-making, and the Research Defence Society (now Understanding Animal Research) was formed in 1908 "to make known the facts as to experiments on animals in this country; the immense importance to the welfare of mankind of such experiments and the great saving of human life and health directly attributable to them".
+Opposition to the use of animals in medical research first arose in the United States during the 1860s, when Henry Bergh founded the American Society for the Prevention of Cruelty to Animals (ASPCA), with America's first specifically anti-vivisection organization being the American AntiVivisection Society (AAVS), founded in 1883. Antivivisectionists of the era generally believed the spread of mercy was the great cause of civilization, and vivisection was cruel. However, in the USA the antivivisectionists' efforts were defeated in every legislature, overwhelmed by the superior organization and influence of the medical community. Overall, this movement had little legislative success until the passing of the Laboratory Animal Welfare Act, in 1966.
+Real progress in thinking about animal rights build on the "theory of justice" (1971) by the philosopher John Rawls and work on ethics by philosopher Peter Singer.
+
+== Alternatives ==

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+---
+title: "Animal testing"
+chunk: 15/15
+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
+instance: "kb-cron"
+---
+
+Most scientists and governments state that animal testing should cause as little suffering to animals as possible, and that animal tests should only be performed when there is no alternative. The "Three Rs" are guiding principles for the use of animals in research in most countries. Whilst replacement of animals, i.e. alternatives to animal testing, is one of the principles, their scope is much broader. Although such principles have been welcomed as a step forwards by some animal welfare groups, they have also been criticized as both outdated by current research, and of little practical effect in improving animal welfare. The scientists and engineers at Harvard's Wyss Institute have created "organs-on-a-chip", including the "lung-on-a-chip" and "gut-on-a-chip". Researchers at cellasys in Germany developed a "skin-on-a-chip". These tiny devices contain human cells in a 3-dimensional system that mimics human organs. The chips can be used instead of animals in in vitro disease research, drug testing, and toxicity testing. Researchers have also begun using 3-D bioprinters to create human tissues for in vitro testing.
+Another non-animal research method is in silico or computer simulation and mathematical modeling which seeks to investigate and ultimately predict toxicity and drug effects on humans without using animals. This is done by investigating test compounds on a molecular level using recent advances in technological capabilities with the ultimate goal of creating treatments unique to each patient. Microdosing is another alternative to the use of animals in experimentation. Microdosing is a process whereby volunteers are administered a small dose of a test compound allowing researchers to investigate its pharmacological affects without harming the volunteers. Microdosing can replace the use of animals in pre-clinical drug screening and can reduce the number of animals used in safety and toxicity testing. Additional alternative methods include positron emission tomography (PET), which allows scanning of the human brain in vivo, and comparative epidemiological studies of disease risk factors among human populations. Simulators and computer programs have also replaced the use of animals in dissection, teaching and training exercises.
+Official bodies such as the European Centre for the Validation of Alternative Test Methods of the European Commission, the Interagency Coordinating Committee for the Validation of Alternative Methods in the US, ZEBET in Germany, and the Japanese Center for the Validation of Alternative Methods (among others) also promote and disseminate the 3Rs. These bodies are mainly driven by responding to regulatory requirements, such as supporting the cosmetics testing ban in the EU by validating alternative methods. The European Partnership for Alternative Approaches to Animal Testing serves as a liaison between the European Commission and industries. The European Consensus Platform for Alternatives coordinates efforts amongst EU member states. Academic centers also investigate alternatives, including the Center for Alternatives to Animal Testing at the Johns Hopkins University and the NC3Rs in the UK.
+
+== See also ==
+
+== References ==
+
+=== Citations ===
+
+=== Works cited ===
+Carbone L (2004). What animals want: expertise and advocacy in laboratory animal welfare policy. Oxford, UK: Oxford University Press. ISBN 978-0-19-972188-7. OCLC 57138138.
+
+== Further reading ==
+
+== External links ==
+ Media related to Animal testing at Wikimedia Commons
+ Quotations related to Animal testing at Wikiquote

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+title: "Animal testing"
+chunk: 3/15
+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
+instance: "kb-cron"
+---
+
+== Model organisms ==
+
+=== Invertebrates ===
+
+Although many more invertebrates than vertebrates are used in animal testing, these studies are largely unregulated by law. The most frequently used invertebrate species are Drosophila melanogaster, a fruit fly, and Caenorhabditis elegans, a nematode worm. In the case of C. elegans, the worm's body is completely transparent and the precise lineage of all the organism's cells is known, while studies in the fly D. melanogaster can use an amazing array of genetic tools. These invertebrates offer some advantages over vertebrates in animal testing, including their short life cycle and the ease with which large numbers may be housed and studied. However, the lack of an adaptive immune system and their simple organs prevent worms from being used in several aspects of medical research such as vaccine development. Similarly, the fruit fly immune system differs greatly from that of humans, and diseases in insects can be different from diseases in vertebrates; however, fruit flies and waxworms can be useful in studies to identify novel virulence factors or pharmacologically active compounds.
+Several invertebrate systems are considered acceptable alternatives to vertebrates in early-stage discovery screens. Because of similarities between the innate immune system of insects and mammals, insects can replace mammals in some types of studies. Drosophila melanogaster and the Galleria mellonella waxworm have been particularly important for analysis of virulent traits of mammalian pathogens. Waxworms and other insects have also proven valuable for the identification of pharmaceutical compounds with favorable bioavailability. The decision to adopt such models generally involves accepting a lower degree of biological similarity with mammals for significant gains in experimental throughput.
+
+=== Rodents ===
+
+In the U.S., the numbers of rats and mice used is estimated to be from 11 million to between 20 and 100 million a year. Other rodents commonly used are guinea pigs, hamsters, and gerbils. Mice are the most commonly used vertebrate species because of their size, low cost, ease of handling, and fast reproduction rate. Mice are widely considered to be the best model of inherited human disease and share 95% of their genes with humans. With the advent of genetic engineering technology, genetically modified mice can be generated to order and can provide models for a range of human diseases. Rats are also widely used for physiology, toxicology and cancer research, but genetic manipulation is much harder in rats than in mice, which limits the use of these rodents in basic science.
+
+=== Dogs ===
+
+Dogs are widely used in biomedical research, testing, and education—particularly beagles, because they are gentle and easy to handle, and to allow for comparisons with historical data from beagles (a Reduction technique). They are used as models for human and veterinary diseases in cardiology, endocrinology, and bone and joint studies, research that tends to be highly invasive, according to the Humane Society of the United States. The most common use of dogs is in the safety assessment of new medicines for human or veterinary use as a second species following testing in rodents, in accordance with the regulations set out in the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. One of the most significant advancements in medical science involves the use of dogs in developing the answers to insulin production in the body for diabetics and the role of the pancreas in this process. They found that the pancreas was responsible for producing insulin in the body and that removal of the pancreas, resulted in the development of diabetes in the dog. After re-injecting the pancreatic extract (insulin), the blood glucose levels were significantly lowered.
+The U.S. Department of Agriculture's Animal Welfare Report shows that 60,979 dogs were used in USDA-registered facilities in 2016. In the UK, according to the UK Home Office, there were 3,847 procedures on dogs in 2017. Of the other large EU users of dogs, Germany conducted 3,976 procedures on dogs in 2016 and France conducted 4,204 procedures in 2016. In both cases this represents under 0.2% of the total number of procedures conducted on animals in the respective countries.
+
+=== Zebrafish ===
+Zebrafish are commonly used for the basic study and development of various cancers. Used to explore the immune system and genetic strains. They are low in cost, small in size, have a fast reproduction rate, and able to observe cancer cells in real time. Humans and zebrafish share neoplasm similarities which is why they are used for research. The National Library of Medicine shows many examples of the types of cancer zebrafish are used in. The use of zebrafish have allowed them to find differences between MYC-driven pre-B vs T-ALL and be exploited to discover novel pre-B ALL therapies on acute lymphocytic leukemia.
+The National Library of Medicine also explains how a neoplasm is difficult to diagnose at an early stage. Understanding the molecular mechanism of digestive tract tumorigenesis and searching for new treatments is the current research. Zebrafish and humans share similar gastric cancer cells in the gastric cancer xenotransplantation model. This allowed researchers to find that Triphala could inhibit the growth and metastasis of gastric cancer cells. Since zebrafish liver cancer genes are related with humans they have become widely used in liver cancer search, as well as many other cancers.
+
+=== Non-human primates ===

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+---
+title: "Animal testing"
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+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
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+date_saved: "2026-05-05T10:01:38.284993+00:00"
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+---
+
+Non-human primates (NHPs) are used in toxicology tests, studies of AIDS and hepatitis, studies of neurology, behavior and cognition, reproduction, genetics, and xenotransplantation. They are caught in the wild or purpose-bred. In the United States and China, most primates are domestically purpose-bred, whereas in Europe the majority are imported purpose-bred. The European Commission reported that in 2011, 6,012 monkeys were experimented on in European laboratories. According to the U.S. Department of Agriculture, there were 71,188 monkeys in U.S. laboratories in 2016. 23,465 monkeys were imported into the U.S. in 2014 including 929 who were caught in the wild. Most of the NHPs used in experiments are macaques; but marmosets, spider monkeys, and squirrel monkeys are also used, and baboons and chimpanzees are used in the US. As of 2015, there are approximately 730 chimpanzees in U.S. laboratories.
+In a survey in 2003, it was found that 89% of singly-housed primates exhibited self-injurious or abnormal stereotypyical behaviors including pacing, rocking, hair pulling, and biting among others.
+The first transgenic primate was produced in 2001, with the development of a method that could introduce new genes into a rhesus macaque. This transgenic technology is now being applied in the search for a treatment for the genetic disorder Huntington's disease. Notable studies on non-human primates have been part of the polio vaccine development, and development of Deep Brain Stimulation, and their current heaviest non-toxicological use occurs in the monkey AIDS model, SIV. In 2008, a proposal to ban all primates experiments in the EU has sparked a vigorous debate.
+
+=== Other species ===
+
+Over 500,000 fish and 9,000 amphibians were used in the UK in 2016. The main species used is the zebrafish, Danio rerio, which are translucent during their embryonic stage, and the African clawed frog, Xenopus laevis. Over 20,000 rabbits were used for animal testing in the UK in 2004. Albino rabbits are used in eye irritancy tests (Draize test) because rabbits have less tear flow than other animals, and the lack of eye pigment in albinos make the effects easier to visualize. The numbers of rabbits used for this purpose has fallen substantially over the past two decades. In 1996, there were 3,693 procedures on rabbits for eye irritation in the UK, and in 2017 this number was just 63. Rabbits are also frequently used for the production of polyclonal antibodies.
+Cats are most commonly used in neurological research. In 2016, 18,898 cats were used in the United States alone, around a third of which were used in experiments which have the potential to cause "pain and/or distress" though only 0.1% of cat experiments involved potential pain which was not relieved by anesthetics/analgesics. In the UK, just 198 procedures were carried out on cats in 2017. The number has been around 200 for most of the last decade.
+
+== Care and use of animals ==
+
+=== Regulations and laws ===

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+title: "Animal testing"
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+
+The regulations that apply to animals in laboratories vary across species. In the U.S., under the Animal Welfare Act and the Guide for the Care and Use of Laboratory Animals (the Guide), published by the National Academy of Sciences, any procedure can be performed on an animal if it can be successfully argued that it is scientifically justified. Researchers are required to consult with the institution's veterinarian and its Institutional Animal Care and Use Committee (IACUC), which every research facility is obliged to maintain. The IACUC must ensure that alternatives, including non-animal alternatives, have been considered, that the experiments are not unnecessarily duplicative, and that pain relief is given unless it would interfere with the study. The IACUCs regulate all vertebrates in testing at institutions receiving federal funds in the USA. Although the Animal Welfare Act does not include purpose-bred rodents and birds, these species are equally regulated under Public Health Service policies that govern the IACUCs. The Public Health Service policy oversees the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC). The CDC conducts infectious disease research on nonhuman primates (due to end, according to an announcement in November 2025), rabbits, mice, and other animals, while FDA requirements cover use of animals in pharmaceutical research. Animal Welfare Act (AWA) regulations are enforced by the USDA, whereas Public Health Service regulations are enforced by OLAW and in many cases by AAALAC.
+According to the 2014 U.S. Department of Agriculture Office of the Inspector General (OIG) report—which looked at the oversight of animal use during a three-year period—"some Institutional Animal Care and Use Committees ...did not adequately approve, monitor, or report on experimental procedures on animals". The OIG found that "as a result, animals are not always receiving basic humane care and treatment and, in some cases, pain and distress are not minimized during and after experimental procedures". According to the report, within a three-year period, nearly half of all American laboratories with regulated species were cited for AWA violations relating to improper IACUC oversight. The USDA OIG made similar findings in a 2005 report. With only a broad number of 120 inspectors, the United States Department of Agriculture (USDA) oversees more than 12,000 facilities involved in research, exhibition, breeding, or dealing of animals. Others have criticized the composition of IACUCs, asserting that the committees are predominantly made up of animal researchers and university representatives who may be biased against animal welfare concerns.
+Larry Carbone, a laboratory animal veterinarian, writes that, in his experience, IACUCs take their work very seriously regardless of the species involved, though the use of non-human primates always raises what he calls a "red flag of special concern". A study published in Science magazine in July 2001 confirmed the low reliability of IACUC reviews of animal experiments. Funded by the National Science Foundation, the three-year study found that animal-use committees that do not know the specifics of the university and personnel do not make the same approval decisions as those made by animal-use committees that do know the university and personnel. Specifically, blinded committees more often ask for more information rather than approving studies.
+Scientists in India are protesting a recent guideline issued by the University Grants Commission to ban the use of live animals in universities and laboratories.
+On April 10, 2025, the FDA announced a Roadmap to Reducing Animal Testing in Preclinical Safety Studies to reduce and phase out animal testing and promote alternatives such as advanced computer simulations and lab grown human "organoids" and organ-on-a-chip systems. Over 90% of drugs that appear safe and effective in animals do not go on to receive FDA approval in humans predominantly due to safety and/or efficacy issues.
+On April 29, 2025, the US NIH announced a new initiative to prioritize human-based research technologies and reduce use of animals in NIH-funded research. On July 8, 2025 at a collaborative FDA & NIH Workshop on Reducing Animal Testing, the NIH announced that NIH will no longer seek proposals exclusively for animal models and that all new NIH funding opportunities moving forward should incorporate language on consideration of NAMs.

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+title: "Animal testing"
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+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
+instance: "kb-cron"
+---
+
+=== Numbers ===
+Accurate global figures for animal testing are difficult to obtain; it has been estimated that 100 million vertebrates are experimented on around the world every year, 10–11 million of them in the EU. The Nuffield Council on Bioethics reports that global annual estimates range from 50 to 100 million animals. None of the figures include invertebrates such as shrimp and fruit flies.The USDA/APHIS has published the 2016 animal research statistics. Overall, the number of animals (covered by the Animal Welfare Act) used in research in the US rose 6.9% from 767,622 (2015) to 820,812 (2016). This includes both public and private institutions. By comparing with EU data, where all vertebrate species are counted, Speaking of Research estimated that around 12 million vertebrates were used in research in the US in 2016. A 2015 article published in the Journal of Medical Ethics, argued that the use of animals in the US has dramatically increased in recent years. Researchers found this increase is largely the result of an increased reliance on genetically modified mice in animal studies.
+In 1995, researchers at Tufts University Center for Animals and Public Policy estimated that 14–21 million animals were used in American laboratories in 1992, a reduction from a high of 50 million used in 1970. In 1986, the U.S. Congress Office of Technology Assessment reported that estimates of the animals used in the U.S. range from 10 million to upwards of 100 million each year, and that their own best estimate was at least 17 million to 22 million. In 2016, the Department of Agriculture listed 60,979 dogs, 18,898 cats, 71,188 non-human primates, 183,237 guinea pigs, 102,633 hamsters, 139,391 rabbits, 83,059 farm animals, and 161,467 other mammals, a total of 820,812, a figure that includes all mammals except purpose-bred mice and rats. The use of dogs and cats in research in the U.S. decreased from 1973 to 2016 from 195,157 to 60,979, and from 66,165 to 18,898, respectively.
+In the UK, Home Office figures show that 3.79 million procedures were carried out in 2017. 2,960 procedures used non-human primates, down over 50% since 1988. A "procedure" refers here to an experiment that might last minutes, several months, or years. Most animals are used in only one procedure: animals are frequently euthanized after the experiment; however death is the endpoint of some procedures.
+The procedures conducted on animals in the UK in 2017 were categorised as: 43% (1.61 million) sub-threshold, 4% (0.14 million) non-recovery, 36% (1.35 million) mild, 15% (0.55 million) moderate, and 4% (0.14 million) severe. A 'severe' procedure would be, for instance, any test where death is the end-point or fatalities are expected, whereas a 'mild' procedure would be something like a blood test or an MRI scan.
+
+=== The Three Rs ===
+
+The Three Rs (3Rs) are guiding principles for more ethical use of animals in testing.  These were first described by W.M.S. Russell and R.L. Burch in 1959. The 3Rs state:
+
+Replacement which refers to the preferred use of methods that do not use animals over methods that use animals whenever possible to achieve the same scientific aims. These methods include computer modeling.
+Reduction which means using the minimum number of animals possible and to obtain as much information as possible from the same number of animals.
+Refinement which refers to methods that alleviate or minimize potential pain, suffering or distress, enhance animal welfare for the animals used, and use non-invasive techniques.
+The 3Rs have a broader scope than simply encouraging alternatives to animal testing, but aim to improve animal welfare and scientific quality where the use of animals can not be avoided.  These 3Rs are now implemented in many testing establishments worldwide and have been adopted by various pieces of legislation and regulations.
+Despite the widespread acceptance of the 3Rs, many countries—including Canada, Australia, Israel, South Korea, and Germany—have reported rising experimental use of animals in recent years with increased use of mice and, in some cases, fish while reporting declines in the use of cats, dogs, primates, rabbits, guinea pigs, and hamsters. Along with other countries, China has also escalated its use of GM animals, resulting in an increase in overall animal use.
+
+=== Sources ===
+
+Animals used by laboratories are largely supplied by specialist dealers. Sources differ for vertebrate and invertebrate animals. Most laboratories breed and raise flies and worms themselves, using strains and mutants supplied from a few main stock centers. For vertebrates, sources include breeders and dealers including Fortrea and Charles River Laboratories, which supply purpose-bred and wild-caught animals; businesses that trade in wild animals such as Nafovanny; and dealers who supply animals sourced from pounds, auctions, and newspaper ads. Animal shelters also supply the laboratories directly. Large centers also exist to distribute strains of genetically modified animals; the International Knockout Mouse Consortium, for example, aims to provide knockout mice for every gene in the mouse genome.

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+title: "Animal testing"
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+
+In the U.S., Class A breeders are licensed by the U.S. Department of Agriculture (USDA) to sell animals for research purposes, while Class B dealers are licensed to buy animals from "random sources" such as auctions, pound seizure, and newspaper ads. Some Class B dealers have been accused of kidnapping pets and illegally trapping strays, a practice known as bunching. It was in part out of public concern over the sale of pets to research facilities that the 1966 Laboratory Animal Welfare Act was ushered in—the Senate Committee on Commerce reported in 1966 that stolen pets had been retrieved from Veterans Administration facilities, the Mayo Institute, the University of Pennsylvania, Stanford University, and Harvard and Yale Medical Schools. The USDA recovered at least a dozen stolen pets during a raid on a Class B dealer in Arkansas in 2003.
+Four states in the U.S.—Minnesota, Utah, Oklahoma, and Iowa—require their shelters to provide animals to research facilities. Fourteen states explicitly prohibit the practice, while the remainder either allow it or have no relevant legislation.
+In the European Union, animal sources are governed by Council Directive 86/609/EEC, which requires lab animals to be specially bred, unless the animal has been lawfully imported and is not a wild animal or a stray. The latter requirement may also be exempted by special arrangement. In 2010 the Directive was revised with EU Directive 2010/63/EU. In the UK, most animals used in experiments are bred for the purpose under the 1988 Animal Protection Act, but wild-caught primates may be used if exceptional and specific justification can be established. The United States also allows the use of wild-caught primates; between 1995 and 1999, 1,580 wild baboons were imported into the U.S. Most of the primates imported are handled by Charles River Laboratories or by Fortrea, which are very active in the international primate trade.
+
+=== Pain and suffering ===
+
+It is generally accepted that animals can feel pain. The extent to which animal testing causes pain and suffering, and the capacity of animals to experience and comprehend them, has been debated.
+According to the USDA, in 2016 501,560 animals (61%) (not including rats, mice, birds, or invertebrates) were used in procedures that did not include more than momentary pain or distress. 247,882 (31%) animals were used in procedures in which pain or distress was relieved by anesthesia, while 71,370 (9%) were used in studies that would cause pain or distress that would not be relieved.
+The idea that animals might not feel pain as human beings feel it traces back to the 17th-century French philosopher, René Descartes, who argued that animals do not experience pain and suffering because they lack consciousness. Bernard Rollin of Colorado State University, the principal author of two U.S. federal laws regulating pain relief for animals, writes that researchers remained unsure into the 1980s as to whether animals experience pain, and that veterinarians trained in the U.S. before 1989 were simply taught to ignore animal pain. In his interactions with scientists and other veterinarians, he was regularly asked to "prove" that animals are conscious, and to provide "scientifically acceptable" grounds for claiming that they feel pain. Carbone writes that the view that animals feel pain differently is now a minority view. Academic reviews of the topic are more equivocal, noting that although the argument that animals have at least simple conscious thoughts and feelings has strong support, some critics continue to question how reliably animal mental states can be determined. However, some canine experts are stating that, while intelligence does differ animal to animal, dogs have the intelligence of a two to two-and-a-half-year old. This does support the idea that dogs, at the very least, have some form of consciousness. The ability of invertebrates to experience pain and suffering is less clear, however, legislation in several countries (e.g. U.K., New Zealand, Norway) protects some invertebrate species if they are being used in animal testing.
+In the U.S., the defining text on animal welfare regulation in animal testing is the Guide for the Care and Use of Laboratory Animals. This defines the parameters that govern animal testing in the U.S. It states "The ability to experience and respond to pain is widespread in the animal kingdom...Pain is a stressor and, if not relieved, can lead to unacceptable levels of stress and distress in animals." The Guide states that the ability to recognize the symptoms of pain in different species is vital in efficiently applying pain relief and that it is essential for the people caring for and using animals to be entirely familiar with these symptoms. On the subject of analgesics used to relieve pain, the Guide states "The selection of the most appropriate analgesic or anesthetic should reflect professional judgment as to which best meets clinical and humane requirements without compromising the scientific aspects of the research protocol". Accordingly, all issues of animal pain and distress, and their potential treatment with analgesia and anesthesia, are required regulatory issues in receiving animal protocol approval. Currently, traumatic methods of marking laboratory animals are being replaced with non-invasive alternatives.
+In 2019, Katrien Devolder and Matthias Eggel proposed gene editing research animals to remove the ability to feel pain. This would be an intermediate step towards eventually stopping all experimentation on animals and adopting alternatives. Additionally, this would not stop research animals from experiencing psychological harm.
+
+=== Euthanasia ===

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+---
+title: "Animal testing"
+chunk: 8/15
+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
+instance: "kb-cron"
+---
+
+Regulations require that scientists use as few animals as possible, especially for terminal experiments. However, while policy makers consider suffering to be the central issue and see animal euthanasia as a way to reduce suffering, others, such as the RSPCA, argue that the lives of laboratory animals have intrinsic value. Regulations focus on whether particular methods cause pain and suffering, not whether their death is undesirable in itself. The animals are euthanized at the end of studies for sample collection or post-mortem examination; during studies if their pain or suffering falls into certain categories regarded as unacceptable, such as depression, infection that is unresponsive to treatment, or the failure of large animals to eat for five days; or when they are unsuitable for breeding or unwanted for some other reason.
+Methods of euthanizing laboratory animals are chosen to induce rapid unconsciousness and death without pain or distress. The methods that are preferred are those published by councils of veterinarians. The animal can be made to inhale a gas, such as carbon monoxide and carbon dioxide, by being placed in a chamber, or by use of a face mask, with or without prior sedation or anesthesia. Sedatives or anesthetics such as barbiturates can be given intravenously, or inhalant anesthetics may be used. Amphibians and fish may be immersed in water containing an anesthetic such as tricaine. Physical methods are also used, with or without sedation or anesthesia depending on the method. Recommended methods include decapitation (beheading) for small rodents or rabbits. Cervical dislocation (breaking the neck or spine) may be used for birds, mice, rats, and rabbits depending on the size and weight of the animal.  High-intensity microwave irradiation of the brain can preserve brain tissue and induce death in less than 1 second, but this is currently only used on rodents. Captive bolts may be used, typically on dogs, ruminants, horses, pigs and rabbits. It causes death by a concussion to the brain. Gunshot may be used, but only in cases where a penetrating captive bolt may not be used. Some physical methods are only acceptable after the animal is unconscious. Electrocution may be used for cattle, sheep, swine, foxes, and mink after the animals are unconscious, often by a prior electrical stun. Pithing (inserting a tool into the base of the brain) is usable on animals already unconscious. Slow or rapid freezing, or inducing air embolism are acceptable only with prior anesthesia to induce unconsciousness.
+
+== Research classification ==
+
+=== Pure research ===
+Basic or pure research investigates how organisms behave, develop, and function. Those opposed to animal testing object that pure research may have little or no practical purpose, but researchers argue that it forms the necessary basis for the development of applied research, rendering the distinction between pure and applied research—research that has a specific practical aim—unclear. Pure research uses larger numbers and a greater variety of animals than applied research. Fruit flies, nematode worms, mice and rats together account for the vast majority, though small numbers of other species are used, ranging from sea slugs through to armadillos. Examples of the types of animals and experiments used in basic research include:
+
+Studies on embryogenesis and developmental biology. Mutants are created by adding transposons into their genomes, or specific genes are deleted by gene targeting. By studying the changes in development these changes produce, scientists aim to understand both how organisms normally develop, and what can go wrong in this process. These studies are particularly powerful since the basic controls of development, such as the homeobox genes, have similar functions in organisms as diverse as fruit flies and man.
+Experiments into behavior, to understand how organisms detect and interact with each other and their environment, in which fruit flies, worms, mice, and rats are all widely used. Studies of brain function, such as memory and social behavior, often use rats and birds. For some species, behavioral research is combined with enrichment strategies for animals in captivity because it allows them to engage in a wider range of activities.
+Breeding experiments to study evolution and genetics. Laboratory mice, flies, fish, and worms are inbred through many generations to create strains with defined characteristics. These provide animals of a known genetic background, an important tool for genetic analyses. Larger mammals are rarely bred specifically for such studies due to their slow rate of reproduction, though some scientists take advantage of inbred domesticated animals, such as dog or cattle breeds, for comparative purposes. Scientists studying how animals evolve use many animal species to see how variations in where and how an organism lives (their niche) produce adaptations in their physiology and morphology. As an example, sticklebacks are now being used to study how many and which types of mutations are selected to produce adaptations in animals' morphology during the evolution of new species.
+
+=== Applied research ===
+Applied research aims to solve specific and practical problems. These may involve the use of animal models of diseases or conditions, which are often discovered or generated by pure research programmes. In turn, such applied studies may be an early stage in the drug discovery process. Examples include:

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+---
+title: "Animal testing"
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+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
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+---
+
+Genetic modification of animals to study disease. Transgenic animals have specific genes inserted, modified or removed, to mimic specific conditions such as single gene disorders, such as Huntington's disease. Other models mimic complex, multifactorial diseases with genetic components, such as diabetes, or even transgenic mice that carry the same mutations that occur during the development of cancer. These models allow investigations on how and why the disease develops, as well as providing ways to develop and test new treatments. The vast majority of these transgenic models of human disease are lines of mice, the mammalian species in which genetic modification is most efficient. Smaller numbers of other animals are also used, including rats, pigs, sheep, fish, birds, and amphibians.
+Studies on models of naturally occurring disease and condition. Certain domestic and wild animals have a natural propensity or predisposition for certain conditions that are also found in humans. Cats are used as a model to develop immunodeficiency virus vaccines and to study leukemia because their natural predisposition to FIV and Feline leukemia virus. Certain breeds of dog experience narcolepsy making them the major model used to study the human condition. Armadillos and humans are among only a few animal species that naturally have leprosy; as the bacteria responsible for this disease cannot yet be grown in culture, armadillos are the primary source of bacilli used in leprosy vaccines.
+Studies on induced animal models of human diseases. Here, an animal is treated so that it develops pathology and symptoms that resemble a human disease. Examples include restricting blood flow to the brain to induce stroke, or giving neurotoxins that cause damage similar to that seen in Parkinson's disease. Much animal research into potential treatments for humans is wasted because it is poorly conducted and not evaluated through systematic reviews. For example, although such models are now widely used to study Parkinson's disease, the British anti-vivisection interest group BUAV argues that these models only superficially resemble the disease symptoms, without the same time course or cellular pathology. In contrast, scientists assessing the usefulness of animal models of Parkinson's disease, as well as the medical research charity The Parkinson's Appeal, state that these models were invaluable and that they led to improved surgical treatments such as pallidotomy, new drug treatments such as levodopa, and later deep brain stimulation.
+Animal testing has also included the use of placebo testing. In these cases animals are treated with a substance that produces no pharmacological effect, but is administered in order to determine any biological alterations due to the experience of a substance being administered, and the results are compared with those obtained with an active compound.
+
+==== Xenotransplantation ====
+
+Xenotransplantation research involves transplanting tissues or organs from one species to another, as a way to overcome the shortage of human organs for use in organ transplants. Current research involves using primates as the recipients of organs from pigs that have been genetically modified to reduce the primates' immune response against the pig tissue. Although transplant rejection remains a problem, recent clinical trials that involved implanting pig insulin-secreting cells into diabetics did reduce these people's need for insulin.
+Documents released to the news media by the animal rights organization Uncaged Campaigns showed that, between 1994 and 2000, wild baboons imported to the UK from Africa by Imutran Ltd, a subsidiary of Novartis Pharma AG, in conjunction with Cambridge University and Huntingdon Life Sciences, to be used in experiments that involved grafting pig tissues, had serious and sometimes fatal injuries. A scandal occurred when it was revealed that the company had communicated with the British government in an attempt to avoid regulation.
+
+=== Toxicology testing ===

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+---
+title: "Animal testing"
+chunk: 10/15
+source: "https://en.wikipedia.org/wiki/Animal_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:38.284993+00:00"
+instance: "kb-cron"
+---
+
+Toxicology testing, also known as safety testing, is conducted by pharmaceutical companies testing drugs, or by contract animal testing facilities, such as Huntingdon Life Sciences, on behalf of a wide variety of customers. According to 2005 EU figures, around one million animals are used every year in Europe in toxicology tests; which are about 10% of all procedures. According to Nature, 5,000 animals are used for each chemical being tested, with 12,000 needed to test pesticides. The tests are conducted without anesthesia, because interactions between drugs can affect how animals detoxify chemicals, and may interfere with the results.
+Toxicology tests are used to examine finished products such as pesticides, medications, food additives, packing materials, and air freshener, or their chemical ingredients. Most tests involve testing ingredients rather than finished products, but according to BUAV, manufacturers believe these tests overestimate the toxic effects of substances; they therefore repeat the tests using their finished products to obtain a less toxic label.
+The substances are applied to the skin or dripped into the eyes; injected intravenously, intramuscularly, or subcutaneously; inhaled either by placing a mask over the animals and restraining them, or by placing them in an inhalation chamber; or administered orally, through a tube into the stomach, or simply in the animal's food. Doses may be given once, repeated regularly for many months, or for the lifespan of the animal.
+There are several different types of acute toxicity tests. The LD50 ("Lethal Dose 50%") test is used to evaluate the toxicity of a substance by determining the dose required to kill 50% of the test animal population. This test was removed from OECD international guidelines in 2002, replaced by methods such as the fixed dose procedure, which use fewer animals and cause less suffering. Abbott writes that, as of 2005, "the LD50 acute toxicity test ... still accounts for one-third of all animal [toxicity] tests worldwide".
+Irritancy can be measured using the Draize test, where a test substance is applied to an animal's eyes or skin, usually an albino rabbit. For Draize eye testing, the test involves observing the effects of the substance at intervals and grading any damage or irritation, but the test should be halted and the animal killed if it shows "continuing signs of severe pain or distress". The Humane Society of the United States writes that the procedure can cause redness, ulceration, hemorrhaging, cloudiness, or even blindness. This test has also been criticized by scientists for being cruel and inaccurate, subjective, over-sensitive, and failing to reflect human exposures in the real world. Although no accepted in vitro alternatives exist, a modified form of the Draize test called the low volume eye test may reduce suffering and provide more realistic results and this was adopted as the new standard in September 2009. However, the Draize test will still be used for substances that are not severe irritants.
+The most stringent tests are reserved for drugs and foodstuffs. For these, a number of tests are performed, lasting less than a month (acute), one to three months (subchronic), and more than three months (chronic) to test general toxicity (damage to organs), eye and skin irritancy, mutagenicity, carcinogenicity, teratogenicity, and reproductive problems. The cost of the full complement of tests is several million dollars per substance and it may take three or four years to complete.
+These toxicity tests provide, in the words of a 2006 United States National Academy of Sciences report, "critical information for assessing hazard and risk potential". Animal tests may overestimate risk, with false positive results being a particular problem, but false positives appear not to be prohibitively common. Variability in results arises from using the effects of high doses of chemicals in small numbers of laboratory animals to try to predict the effects of low doses in large numbers of humans. Although relationships do exist, opinion is divided on how to use data on one species to predict the exact level of risk in another.
+Scientists face growing pressure to move away from using traditional animal toxicity tests to determine whether manufactured chemicals are safe.
+Among variety of approaches to toxicity evaluation the ones which have attracted increasing interests are in vitro cell-based sensing methods applying fluorescence.
+
+==== Cosmetics testing ====
+
+Cosmetics testing on animals is particularly controversial. Such tests, which are still conducted in the U.S., involve general toxicity, eye and skin irritancy, phototoxicity (toxicity triggered by ultraviolet light) and mutagenicity.
+Cosmetics testing on animals is banned in India, the United Kingdom, the European Union, Israel and Norway while legislation in the U.S. and Brazil is currently considering similar bans. In 2002, after 13 years of discussion, the European Union agreed to phase in a near-total ban on the sale of animal-tested cosmetics by 2009, and to ban all cosmetics-related animal testing. France, which is home to the world's largest cosmetics company, L'Oreal, has protested the proposed ban by lodging a case at the European Court of Justice in Luxembourg, asking that the ban be quashed. The ban is also opposed by the European Federation for Cosmetics Ingredients, which represents 70 companies in Switzerland, Belgium, France, Germany, and Italy. In October 2014, India passed stricter laws that also ban the importation of any cosmetic products that are tested on animals.
+
+=== Drug testing ===
+Before the early 20th century, laws regulating drugs were lax. Currently, all new pharmaceuticals undergo rigorous animal testing before being licensed for human use. Tests on pharmaceutical products involve:

data/en.wikipedia.org/wiki/Aramaic_New_Testament_hypotheses-0.md

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+---
+title: "Aramaic New Testament hypotheses"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Aramaic_New_Testament_hypotheses"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:01.547733+00:00"
+instance: "kb-cron"
+---
+
+Aramaic New Testament hypotheses are a number of hypotheses within Biblical scholarship which argue that the Christian New Testament derives in some form from an Aramaic original. A first version was initially advanced in the 17th and 18th centuries, arguing that all Gospels and Acts could derive from one Aramaic proto-Gospel. Subsequent current-day hypotheses trying to better establish this earlier hypothesis, usually argue some parts of the Gospels could derive from an Aramaic sayings-source. In current scholarship they enjoy no notable support compared to the consensus hypothesis that the New Testament was written in Koine Greek.
+They are related to and often overlap with the Hebrew Gospel hypothesis, which posits a similar idea but with Hebrew instead of Aramaic.
+
+
+== Greek original New Testament hypothesis ==
+
+The current consensus view held by almost all scholars of the New Testament is that all of its contents were originally written in Koine Greek.
+
+An example of how mainstream scholars have dealt with Aramaic influences within an overall view of the Gospels' original Greek-language development may be found in Martin Hengel's synthesis of studies of the linguistic situation in Palestine during the time of Jesus and the Gospels:Since non-literary, simple Greek knowledge or competency in multiple languages was relatively widespread in Jewish Palestine including Galilee, and a Greek-speaking community had already developed in Jerusalem shortly after Easter, one can assume that this linguistic transformation [from "the Aramaic native language of Jesus" to "the Greek Gospels"] began very early.  ...  [M]issionaries, above all 'Hellenists' driven out of Jerusalem, soon preached their message in the Greek language. We find them in Damascus as early as AD 32 or 33. A certain percentage of Jesus' earliest followers were presumably bilingual and could therefore report, at least in simple Greek, what had been heard and seen. This probably applies to Cephas/Peter, Andrew, Philip or John. Mark, too, who was better educated in Jerusalem than the Galilean fishermen, belonged to this milieu.  The great number of phonetically correct Aramaisms and his knowledge of the conditions in Jewish Palestine compel us to assume a Palestinian Jewish-Christian author.  Also, the author's Aramaic native language is still discernible in the Marcan style.
+
+
+== Aramaic original New Testament hypotheses ==
+The hypothesis that the New Testament could have been written in Aramaic, the language of Jesus, and then translated to Greek is rejected by the majority of modern scholars.
+Richard Simon of Normandy in 1689 initially asserted that an Aramaic or Hebrew Gospel of Matthew, lay behind the Nazarene Gospel, and was the Proto-Gospel. A more extensive version of this theory only claiming an Aramaic Proto-Gospel was first proposed by Gotthold Ephraim Lessing in 1784. It was expounded on by Johann Gottfried Eichhorn, who in 1804 provided a comprehensive basis for the Proto-Gospel hypothesis and argued for an Aramaic original gospel that each of the Synoptic evangelists had in a different intermediate form.
+In 1887 John Hancock Pettingell in spite of the then-well established view of Greek originals, argued that some texts of the New Testament such as "the Gospel of Matthew, the Epistles to the Hebrews" might have been written "in the vernacular Syriac of the Jews". Some 19th-century scholars believe the place names in the Peshitta New Testament indicate it was written by someone with independent knowledge of Aramaic place names in Palestine mentioned in the Greek New Testament.
+Throughout the 20th century Matthew Black tried to advance Lessing's hypothesis further, but only was able to establish with some degree of certainty that some parts of the Gospel of Mark could derive from an Aramaic sayings-source or tradition. His work was heavily critiqued for its methodology. It is republished today with a critical preface lauding it as the "highmark" of an older theory, but describing consequent developments in scholarship.
+The 20th-century scholar Charles Cutler Torrey held to a view that the Gospels were composed in Aramaic. He also argued in a posthumous publication that the Greek in the Book of Revelation was so bad that it might be indicative of having been composed in Aramaic.
+The 20th-century Vetus Syra translator E. Jan Wilson believed that Luke was written "in the Syriac dialect of Antioch", that Matthew also might be an Aramaic composition, that Mark was unlikely to be Aramaic and that John could not have been written in Aramaic.  Fellow 20th-century translator George Lamsa advocated for a similar Syriac-based theory asserting a "Peshitta-original" in his translation of his Peshitta New Testament. However, his work is poorly regarded by most scholars in the field.
+The common response by scholars in the field of New Testament studies to these theories is expressed by Sebastian Brock:
+
+The only complete English translation of the Peshitta is by G. Lamsa. This is unfortunately not always very accurate, and his claims that the Peshitta Gospels represent the Aramaic original underlying the Greek Gospels are entirely without foundation; such views, which are not infrequently found in more popular literature, are rejected by all serious scholars.
+
+
+== Outside of academia ==
+At times leaders of the Assyrian Church of the East express the belief that the entire Syriac Peshitta New Testament in liturgical use by them is the original of the New Testament. However, almost all modern scholars view its Old Testament as a 2nd-century translation from Hebrew and its New Testament as a 5th-century translation from Greek.
+Claims exalting Aramaic in such ways are directly connected to the emergence and current expression of Assyrian nationalism. Similar beliefs are present in various Messianic Jewish groups.
+
+
+== See also ==
+List of English Bible translations#Modern Aramaic to English translations
+
+
+== References ==
+
+
+== Further reading ==
+Ben-Hayyim, Z. (1957–1977), The Literary and Oral Tradition of Hebrew and Aramaic amongst the Samaritans, Jerusalem Academy of the Hebrew Language
+Black, M. (1967), An Aramaic Approach to the Gospels and Acts. 3rd Ed., Hendrickson Publishers
+Burney, C. F. (1922), The Aramaic Origin of the Fourth Gospel, Oxford at the Clarendon Press
+Casey, M. (1998), The Aramaic Sources of Mark's Gospel, Cambridge University Press
+Casey, M. (2002), An Aramaic Approach to Q, Cambridge University Press
+Fitzmyer, J. (1997), The Semitic Background of the New Testament, Eerdmans Publishing
+Lamsa, G. (1976), New Testament Origin, Aramaic Bible Center
+Montgomery, James A. (1923). The Origin of the Gospel According to St. John. Philadelphia: John C. Winston Co.
+Torrey, Charles Cutler (1916). The Composition and Date of Acts. Harvard Theological Studies. Cambridge, MA: Harvard University Press.
+Torrey, Charles Cutler (1936). Our Translated Gospels: Some of the Evidence. New York: Harper & Brothers.
+Torrey, C. (1941), Documents of the Primitive Church, Harper & Brothers
+Zimmermann, F. (1979), The Aramaic Origin of the Four Gospels, Ktav Publishing House

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+---
+title: "Art-based research"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Art-based_research"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:40.700649+00:00"
+instance: "kb-cron"
+---
+
+Art-based research is a mode of formal qualitative inquiry that uses artistic processes  in order to understand and articulate the subjectivity of human experience.
+
+
+== History ==
+The term was first coined by Elliot Eisner, who was a professor of Art and Education at the Stanford Graduate School of Education and one of the United States' leading academic minds.
+Eisner used the term "art-based research" as the title of a conference presentation held at Stanford University in 1993.
+Subsequently, the concept of art-based research was defined by Shaun McNiff, professor of Creative Arts Therapies at Lesley College, as "the systematic use of the artistic process, the actual making of artistic expressions in all of the different forms of the arts, as a primary way of understanding and examining experience by both researchers and the people that they involve in their studies". It was later additionally defined as "research that uses the arts, in the broadest sense, to explore, understand, represent and even challenge human action and experience".
+Many practitioners of art-based research trace the origins of their approach to the work of German arts theorist and psychologist Rudolf Arnheim, and American philosopher Susanne Langer, both of whom elucidated the use of artistic experimentation and production as a means by which to acquire and document knowledge about the art, the artist, and its audience, inspiring a range of academic programs that facilitated students in using the process of making art, including performance, painting, and music as the means by which to understand the nature of human experience, teaching, and learning.
+Arts-Based research is often paired with action research, participatory action research and community-based participatory research methodologies.
+Today, art-based research is employed not only in arts education, but also in health care, management, the social and behavioral sciences, and the technology sector.
+
+
+== Branches ==
+
+
+=== Feminist arts-based research ===
+Feminist arts-based research draws on the principles of the feminist movement and feminist art, committed to gender equality as it intersects with the vast array of social life and social justice issues. Feminist arts-based research requires researchers to critically reflect on their practice and positionally as artists and researchers. As Karen Keifer-Boyd states, feminist arts-based research "examines gender inequalities manifested in different forms of privilege and oppression, and exposes the pervasiveness of gender entangled with race and class in structuring social life".
+
+
+=== Queer arts-based research ===
+Drawing on queer studies and theory as well the historical artistic activism of the LGBT movements such as ACT UP or the NAMES Project AIDS Memorial Quilt, queer arts-based research seeks to question and deconstruct normative binaries, hetero- and cis-normativity, and make space for queer ways of knowing and being in the world. Oxford Research Encyclopedias on Communication state that queer arts-based research "allows individuals to question the taken-for-granted conventions that shape social understanding of gender, sex, and sexuality in a subjective and participatory way".
+
+
+=== Disability arts-based research ===
+Disability arts-based research focuses on addressing negative ideology regarding disability through building knowledge from and with people with disabilities, and challenge discourses about disabled people without their involvement. Following the values of the disability rights movement, researchers and participants engaging in disability arts-based research are committed to maintain voice, agency, and dignity for disabled people.
+
+
+== A/r/tography ==
+Expanding on Eisner's ideas, researchers in Canada developed a discipline they named "a/r/tography", a hybrid form of practice-based research within education and the arts. A/r/tography stands for artmaking, researching, and teaching. It is a popular methodology for artists, teachers and makers in which a/r/tography transforms information and the relationships between art-making, research and theory in order to inform the public on various issues. For example, Australian artist, art theorist, and educator, Graeme Sullivan, states that "Arts-informed researchers, [artographers], and the like, have a similar interest in schools, community and culture, but their focus is on developing the practitioner-researcher who is capable of imaginative and insightful inquiry."
+Further developments in arts-based approaches as a means of communicating complex research ideas from diverse research sources have been integral to practical and conceptual innovations, merging the domains of arts-based research and knowledge translation research in the health science and the social sciences. This domain of arts-based knowledge translation has been developed by Mandy Archibald, assistant professor and interdisciplinary artist at the University of Manitoba and others.
+
+
+== References ==

data/en.wikipedia.org/wiki/Astronomy_Centre-0.md

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+---
+title: "Astronomy Centre"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Astronomy_Centre"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:13.184580+00:00"
+instance: "kb-cron"
+---
+
+The Astronomy Centre, also known as the Amateur Astronomy Centre, is an astronomical observatory located in northern England which is run by experienced amateur astronomers and is open to the public at certain times.
+
+
+== History and purpose ==
+Founded in November 1982 by Peter Drew, Linda Simonian and Rob Miller on the site of a disused factory, high in the Pennines, the Centre provides opportunities for its members, schools, local community groups and the general public to observe and photograph astronomical phenomena at a range of wavelengths during daylight and night hours.
+At the time the Centre was conceived, access to equipment and expertise was unavailable for many amateur astronomers in the UK and a national centre would have provided an invaluable focal point. Developments in optical fabrication, photography and communications now permit many visitors and members to complement their home astronomical facilities, skills and experience with those of the Astronomy Centre.
+In keeping with the Centres original ethos, besides welcoming visitors to the facility, current members engage off-site with schools, youth organisations and community groups and also provide contributions to national, regional, local print and broadcast media.
+
+
+== Structures ==
+The first permanent housing on the site was built to shelter a 17 inches (430 mm) aperture Newtonian telescope. Further construction took the total number of separate telescope mountings to 14 by the end of 2015.
+The main observatory tower is a three level 29 feet (8.8 m) round building topped by an aluminium dome with twin 3 feet (0.91 m) sliding doors. Its construction by the members was completed in April 2000.
+
+
+== Telescopes and other instruments ==
+The largest optical telescope currently in regular use is a 30 inches (760 mm) open truss Newtonian on a mount inspired by the designs of John Dobson. A 42.6 inches (1,080 mm) mirror blank is available for a future enhancement of the facilities but construction of the UK's largest reflector since the destruction of the 98 inches (2,500 mm) original Isaac Newton Telescope at Herstmonceux Castle is currently on hold.
+In addition to the permanently mounted 30", 20", 17", 16", 12" and 8" instruments there are fixed locations to allow a number of smaller portable items to be quickly set up if visitor numbers increase on a clear night.
+Many of the optical instruments were constructed by telescope maker Peter Drew, who has also provided many other societies and individuals (such as Hoober Observatory) with their equipment. This includes a number of cameras obscura similar to, but smaller than, the one installed on the main Observatory building.
+
+
+== Public and community access ==
+Observational astronomy takes place on weekly open nights, for special events and by special arrangement with keyholders. As well as the basics of visual astronomy  visitors can undertake a wide range of more advanced observations guided by volunteers with long experience in safe solar astronomy, infra-red astronomy and radio astronomy.
+
+
+== References ==
+
+
+== External links ==
+Official website
+The Astronomy Centre on Go Stargazing

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+---
+title: "Augustinian hypothesis"
+chunk: 1/4
+source: "https://en.wikipedia.org/wiki/Augustinian_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:02.720328+00:00"
+instance: "kb-cron"
+---
+
+The Augustinian hypothesis (sometimes referred to as the Augustinian Proposal) is a solution to the synoptic problem, which concerns the origin of the Gospels of the New Testament. The hypothesis holds that Matthew was written first, by Matthew the Evangelist (see the Gospel According to the Hebrews and the Jewish-Christian Gospels). Mark the Evangelist wrote the Gospel of Mark second and used Matthew and the preaching of Peter as sources. Luke the Evangelist wrote the Gospel of Luke and was aware of the two Gospels that preceded him. Unlike some competing hypotheses, this hypothesis does not rely on, nor does it argue for, the existence of any document that is not explicitly mentioned in historical testimony. Instead, the hypothesis draws primarily upon historical testimony, rather than textual criticism, as the central line of evidence. The foundation of evidence for the hypothesis is the writings of the Church Fathers: historical sources dating back to as early as the first half of the 2nd century, which have been held as authoritative by most Christians for nearly two millennia. Adherents to the Augustinian hypothesis view it as a simple, coherent solution to the synoptic problem.
+The Augustinian hypothesis addresses certain fundamental points of contention surrounding the synoptic problem, such as how reliable the early Christian tradition is, which gospel was written first, whether there were other unknown sources behind the gospels, to what extent, if any, the gospels were redacted, and to what extent the gospels were altered between the time they were originally written and the time the first surviving manuscripts appear. These and other matters are raised and alternate resolutions proposed by proponents of competing hypotheses, such as the Two-source hypothesis, its related Q hypothesis, the Farrer hypothesis, and others.
+The main two areas of contention within the Augustinian community are whether Matthew was originally written in Aramaic using Hebrew script (see Aramaic primacy), or if the Greek text is the original, and whether it was Mark or Luke who wrote second. A modified version of the Augustinian hypothesis, known as the Griesbach hypothesis, agrees that Matthew wrote first and that Mark depended on Matthew, and does not dispute that the original text was in Hebrew thereafter translated into Greek, but argues that Mark also depended on Luke and therefore that Luke’s gospel precedes Mark's. Because of the similarity on primary points of contention, this hypothesis is also treated as a possible amendment to the Augustinian hypothesis.
+
+== Origin ==
+
+The hypothesis takes its name from Augustine of Hippo, an early 5th century bishop and church father, who wrote: "Now, those four evangelists whose names have gained the most remarkable circulation over the whole world, and whose number has been fixed as four, ...are believed to have written in the order which follows: first Matthew, then Mark, thirdly Luke, lastly John." And: "Of these four, it is true, only Matthew is reckoned to have written in the Hebrew language; the others in Greek. And however they may appear to have kept each of them a certain order of narration proper to himself, this certainly is not to be taken as if each individual writer chose to write in ignorance of what his predecessor had done..."
+Mark was famously dubbed by Augustine as "pedissequus et breviator Matthaei", the attendant and abbreviator of Matthew, in direct contrast to the view most commonly held in academia today, that Mark's gospel was the earliest. Augustine also discussed the commonalities between the Synoptic Gospels, including the identical language found in Matthew, Mark, and Luke. Augustine was not the first to articulate this view, as Irenaeus and Origen, among others, shared this ordering. However, Augustine is the earliest extant author to give a detailed scholarly textual analysis of the three texts' interdependence, and to articulate a theory for the express purpose of explaining this fact.
+
+== Ancient tradition ==
+
+The Church Fathers who wrote about the order and authorship of the canonical gospels all supported some basic ideas of the Augustinian hypothesis. The fathers whose writings survive and who wrote about authorship are almost unanimous in agreement that Matthew the apostle was the author, wrote first, and did so for the Hebrews in their language.  A number of sources in antiquity asserted that Mark wrote his Gospel after Matthew based on the preaching of Peter. Various elements of this tradition are found in the writings of Irenaeus, Origen, Eusebius, and others.
+The text of the Gospel itself circulated with a title "According to Matthew", a tradition indisputably acknowledged before the close of the 2nd century.  In addition, the title "According to Matthew" is found in the earliest manuscripts.  A number of scholars have argued that the title must be dated no later than 125. Many contemporary scholars, however, believe it was originally anonymous.
+The earliest surviving references to the gospel tradition are quoted by Eusebius (lived c. 263–339 CE), and different but related traditions appear in the works of Papias (wrote during the first half of 2nd century CE) and the works of Clement. A third ancient source, Irenaeus, also provides further information about the traditions, especially that of Papias, and possibly adds a third related tradition to the sources. These related traditions generally agree on the primary points of contention within the Augustinian hypothesis, though not without discrepancies. Rather than seen as a refutation to the hypothesis, instead these discrepancies are often cited in defense of the hypothesis because they counter the argument that the entire tradition is merely a repetition of Papias's original assertion (therefore, if he were wrong, the great many historical sources supporting the theory would be inconsequential). Instead, slight disagreement is actually in favor of multiple, near identical traditions.

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+---
+title: "Augustinian hypothesis"
+chunk: 2/4
+source: "https://en.wikipedia.org/wiki/Augustinian_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:02.720328+00:00"
+instance: "kb-cron"
+---
+
+=== Papias ===
+According to Irenaeus, Papias was "a hearer of John and a companion of Polycarp, a man of primitive times," who wrote a volume in "five books." The benefit of historical immediacy, as argued by D. H. Fischer is one of the key determinants of historicity, and the church father Papias is a very early source in regard to testimony that the Matthew wrote his gospel first. Papias wrote that: "Matthew compiled the sayings in the Hebrew language, and everyone translated them as well he could." (The 'Hebrew language' referred to by Papias has often been interpreted as Aramaic.)
+It has been argued, because Papias does not cite an authority for his assertions concerning Matthew but does concerning Mark, that Matthew was already fully accepted at the time of his writings.
+
+=== Clement ===
+Eusebius also recorded an important tradition from Clement of Alexandria (died c. 213):
+
+In the same volumes Clement has found room for a tradition of the primitive authorities of the Church regarding the order of the gospels. It is this. He used to say that the earliest gospels were those containing the genealogies [Matthew, Luke], while Mark's originated as follows: When, at Rome, Peter had openly preached the word and by the Spirit had proclaimed the gospel, the large audience urged Mark, who had followed him for a long time and remembered what had been said, to write it all down. This he did, making his gospel available to all who wanted it. When Peter heard about this, he made no objection and gave no special encouragement. Last of all, aware that the physical facts had been recorded in the gospels, encouraged by his pupils and irresistibly moved by the Spirit, John wrote a spiritual gospel.
+This source claims multiple authorities of antiquity, not merely Papias; this is taken as evidence against the view that the testimony of the Fathers is based solely upon the witness of Papias. Furthermore the tradition of Clement concurs with the significant point of contention: Matthean priority. However, Clement conflicts with the Augustinian hypothesis concerning the order of Mark and Luke. The Griesbach hypothesis attempts to resolve the difficulty concerning this secondary point of contention by stating Luke wrote before Mark.
+
+=== Irenaeus ===
+Irenaeus, who was familiar with the work of Papias and who knew Polycarp and possibly even the apostle John, wrote: "Now Matthew published also a book of the Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching the gospel in Rome and founding the Church."
+He is quoted by Eusebius as saying:
+
+2. Matthew published his Gospel among the Hebrews in their own language, while Peter and Paul were preaching and founding the church in Rome.
+3. After their departure Mark, the disciple and interpreter of Peter, also transmitted to us in writing those things which Peter had preached; and Luke, the attendant of Paul, recorded in a book the Gospel which Paul had declared.
+4. Afterwards John, the disciple of the Lord, who also reclined on his bosom, published his Gospel, while staying at Ephesus in Asia.
+
+Irenaeus gives here another tradition in accord with Papias, though containing more information. This has been taken as evidence of a third, yet harmonious tradition.  However, Irenaeus places the composition of Mark after Peter's death, while Clement (and others, such as Origen and Eusebius) claimed Peter was alive and approved the work. Nonetheless, his chronology of the composition of the books does accord with the Augustinian hypothesis (which does not directly address whether Peter was alive at the time of the composition of Mark).
+An original Aramaic version of Matthew does not exist in the sense that no copy survives in the original language today. Many proponents of the Augustinian hypothesis hold that the current Greek Matthew is a complete translation of the original Aramaic Matthew. This theory has strong support in a number of Church Fathers. Papias, Irenaeus, Origen, Eusebius, Epiphanius and Jerome all agree that the original Matthew was written in Hebrew. Jerome even claimed to have seen the original Aramaic Matthew in the library of Pamphilus the Martyr.  Eusebius wrote in c. 325 that Pantaerus found a copy of the Gospel of Matthew written in Hebrew in India, and that it had been left there by Bartholomew. In c. 376, Epiphanius wrote there was "no doubt" that a sect in Palestine still used the original Hebrew text "just as it was originally written." And, of course, Augustine also repeated this tradition. To these authors should be added Pantaenus, Athanasius, John Chrysostom, Cyril of Jerusalem, Gregory of Nazianzus, and others in agreement. However, most modern scholars believe Matthew was originally composed in Greek (see Aramaic New Testament hypotheses and Hebrew Gospel hypothesis).
+
+== Augustinian revival ==

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+---
+title: "Augustinian hypothesis"
+chunk: 3/4
+source: "https://en.wikipedia.org/wiki/Augustinian_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:02.720328+00:00"
+instance: "kb-cron"
+---
+
+The Augustinian position, and the similar Griesbach hypothesis, has drawn recent interest, especially from B. C. Butler, John Wenham, W.R. Farmer, and others as an alternative solution to the synoptic problem, and has been employed as a scholarly refutation of Marcan priority, the Q hypothesis, and the two-source hypothesis.
+Butler argued that accepting the priority of Matthew rendered it possible to dispense with the hypothetical Q document altogether, a position he supported by arguments concerning the inadmissibility of appealing to Q as a sound explanation of the cases where Matthew appears to be more original than Mark.
+Likewise it has been pointed out that differences between the Synoptic Gospels are as easily explained by differing purposes of the authors than by forced redactions or omissions due to ignorance.  Furthermore, against certain arguments that the “primitiveness” of the ideas within the Gospels is the determining factor in their literary interdependence, it is observed that defining "primitiveness" carries obvious difficulties.
+Farmer argued that a modification of the Augustinian hypothesis, the so-called Two-gospel hypothesis, ordering Matthew-Luke-Mark, eliminated all reasons for the existence of Q, a position whose credibility was conceded by W.C. Allen and others. Bernard Orchard also developed the Two-gospel hypothesis and suggested a plausible historic scenario that merged its ideas with the historic evidence that underlines the Augustinian hypothesis.
+
+=== Modern position in detail ===
+Recently, modern scholars accepting some form of the Augustinian hypothesis have attempted to develop a detailed argument explaining the theoretical origin of the gospels. There was a perceived need for this in response to recent competing theories, expressed by Bernard Orchard: “the two-document hypothesis and the priority of Mark are still only hypotheses, not infallible dogmas, and they have stood secure for so long chiefly because no one has been able to offer any satisfactory alternative."  Central to this process is the assumption that the gospel's development should be understood as a reaction to various developing needs of the early church.
+John Wenham argued that, in the early Jerusalem Church, there would have been an early need for the production of a written record to augment the "atmosphere of spontaneity" within which the apostles, disciples, and eyewitnesses would have given instruction. The reasons for this, he asserted, were: the need for instruction when no qualified teacher was available, the need for consistency and accuracy in what was taught as it spread throughout the first scattered Christian communities, and for the basic need of evangelization.  Wenham also argued that Matthew was a natural choice since, as a tax collector, he would have had the requisite literacy, as well as his first hand memories, and perhaps even notes.  Others have observed that persecutions in Palestine, threatening dispersion of the Christians, would have been a motivating factor for a text of the life of Jesus.
+The majority Hebrew makeup of the primitive Church has been seen as support of Aramaic primacy.  Besides the traditional material (see above), other support for an Aramaic Matthew advanced in recent years includes the theory that the Medieval Hebrew gospel of Matthew in Even Bohan could be a corrupted version of the original.
+Bernard Orchard identified the above period as a "first phase" of the development of the Gospels, distinguished from the subsequent phase by the events of the year 42:

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+---
+title: "Augustinian hypothesis"
+chunk: 4/4
+source: "https://en.wikipedia.org/wiki/Augustinian_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:02.720328+00:00"
+instance: "kb-cron"
+---
+
+A savage persecution of the Church, begun by Herod Agrippa I in AD 42, was the signal for the dispersion of the apostles now possessing in the Gospel of Matthew the necessary tool to support and confirm their preaching, while at the same time preserving their theological unity. The first phase was completed, and the second phase of the Church's expansion was about to begin with the mission of Paul.
+Central to Orchard's characterization of this new second phase is the distinction between a primarily Hebrew orientation and a primarily Greek orientation, focusing not only on the Jewish converts to Christianity, but to the gentile converts as well. This, he argues, resulted in three key events: the translation of the original Matthew into Greek, the production of the Gospel of Mark within the context of Peter's preaching to Greek speaking converts in Rome, and Luke's authorship of his Gospel under the instruction of Paul. Cited in support of this are the comments of Clement, Irenaeus, and others who state that the Gospel of Mark was written by Mark, a follower of the apostle Peter, based on his speeches. Orchard countered the claim that the Gospel of Mark must have been written first, since it contains less information than Matthew and Luke, by positing that Peter elected not to speak on certain subjects, such as the birth and resurrection narratives, since he had not been a direct witness of those events.
+The notion that Peter employed Matthew in his preaching was supported by B.C. Butler, but not by John Wenham, who instead explained the similar structure by arguing simply that Mark used both his recollection of his instruction from the Gospel of Matthew and his memory of the preaching of Peter to pen his own synthesis.
+The association of the Gospel of Luke with Paul the apostle, which is witnessed by tradition, has led some to argue that Luke was with Paul during his imprisonment in Rome, or to at least place the date of composition prior to 70 and the fall of Jerusalem.  The author of Luke also wrote in his prologue that he employed various sources in composing his work. Wenham argued that an excess of such material, along with the constraints of scroll length, was one cause of his noticeable omission of material found in Matthew and Mark.
+An unusual modern scholar who supported the notion that the Synoptic Gospels were of an early date, specifically before 70, was John Robinson. Though generally considered a liberal theologian, his views in respect to the development of the Gospels were consistent with the Augustinian hypothesis. He wrote in his work Redating the New Testament that past scholarship was based on a "tyranny of unexamined assumptions" and an "almost wilful blindness," concluding that New Testament was written before 64, and that there is no compelling evidence and little evidence of any kind that anything in the New Testament reflects knowledge of the Temple's destruction. Furthermore, in relation to the four gospels, according to Norman Geisler:
+
+"Robinson places Matthew at 40 to after 60, Mark at about 45 to 60, Luke at before 57 to after 60, and John at from 40 to after 65."
+
+== Explanatory notes ==
+
+== See also ==
+
+Farrer hypothesis
+Four-document hypothesis
+Gospel harmony
+Griesbach hypothesis
+Hebrew Gospel hypothesis
+Two-source hypothesis
+
+== References ==
+
+== External links ==
+Evaluation of the Theory of Literary Dependence
+The Mysterious Case of the Missing Q Archived 2002-08-02 at the Wayback Machine
+Synoptic Problem Website

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+title: "Availability heuristic"
+chunk: 1/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+The availability heuristic, also known as availability bias, is a mental shortcut that relies on immediate examples that come to a given person's mind when evaluating a specific topic, concept, method, or decision. This heuristic, operating on the notion that, if something can be quickly recalled, it must be important, or at least more important than alternative solutions not as readily recalled, is inherently biased toward recently acquired information.
+The mental availability of an action's consequences is positively related to those consequences' perceived magnitude. In other words, the easier it is to recall the consequences of something, the greater those consequences are often perceived to be. Most notably, people often rely on the content of their recall if its implications are not called into question by the difficulty they have in recalling it.
+
+== Overview and history ==
+
+In the late 1960s and early 1970s, Amos Tversky and Daniel Kahneman began work on a series of papers examining "heuristic and biases" used in judgment under uncertainty. Prior to that, the predominant view in the field of human judgment was that humans are rational actors. Kahneman and Tversky explained that judgment under uncertainty often relies on a limited number of simplifying heuristics rather than extensive algorithmic processing. Soon, this idea spread beyond academic psychology, into law, medicine, and political science. This research questioned the descriptive adequacy of idealized models of judgment, and offered insights into the cognitive processes that explained human error without invoking motivated irrationality. One simplifying strategy people may rely on is the tendency to make a judgment about the frequency of an event based on how many similar instances are brought to mind. In 1973, Amos Tversky and Daniel Kahneman first studied this phenomenon and labeled it the "availability heuristic". An availability heuristic is a mental shortcut that relies on immediate examples that come to a given person's mind when evaluating a specific topic, concept, method, or decision. As follows, people tend to use a readily available fact to base their beliefs on a comparably distant concept. There has been much research done with this heuristic, but studies on the issue are still questionable with regard to the underlying process. Studies illustrate that manipulations intended to increase the subjective experience of ease of recall are also likely to affect the amount of recall. Furthermore, this makes it difficult to determine whether the obtained estimates of frequency, likelihood, or typicality are based on participants' phenomenal experiences or on a biased sample of recalled information.
+However, some textbooks have chosen the latter interpretation introducing the availability heuristic as "one's judgments are always based on what comes to mind". For example, if a person is asked whether there are more words in the English language that start with a k or have k as the third letter, the person will probably be able to think of more words that begin with the letter k, concluding incorrectly that k is more frequent as the first letter than the third. In this Wikipedia article itself, for example, there are multiple instances of words such as "likely", "make", "take", "ask" and indeed "Wikipedia", but (aside from names) only a couple of initial K's: "know" and "key".
+
+== Research ==
+Chapman (1967) described a bias in the judgment of the frequency with which two events co-occur. This demonstration showed that the co-occurrence of paired stimuli resulted in participants overestimating the frequency of the pairings. To test this idea, participants were given information about several hypothetical mental patients. The data for each patient consisted of a clinical diagnosis and a drawing made by the patient. Later, participants estimated the frequency with which each diagnosis had been accompanied by various features of the drawing. The subjects vastly overestimated the frequency of this co-occurrence (such as suspiciousness and peculiar eyes). This effect was labeled the illusory correlation. Tversky and Kahneman suggested that availability provides a natural account for the illusory-correlation effect. The strength of the association between two events could provide the basis for the judgment of how frequently the two events co-occur. When the association is strong, it becomes more likely to conclude that the events have been paired frequently. Strong associations will be thought of as having occurred together frequently.
+In Tversky & Kahneman's first examination of availability heuristics, subjects were asked, "If a random word is taken from an English text, is it more likely that the word starts with a K, or that K is the third letter?" They argue that English-speaking people would immediately think of many words that begin with the letter "K" (kangaroo, kitchen, kale), but that it would take a more concentrated effort to think of any words in which "K" is the third letter (acknowledge, ask). Results indicated that participants overestimated the number of words that began with the letter "K" and underestimated the number of words that had "K" as the third letter. Tversky and Kahneman concluded that people answer questions like these by comparing the availability of the two categories and assessing how easily they can recall these instances. In other words, it is easier to think of words that begin with "K", more than words with "K" as the third letter. Thus, people judge words beginning with a "K" to be a more common occurrence. In reality, however, a typical text contains twice as many words that have "K" as the third letter than "K" as the first letter.
+In Tversky and Kahneman's seminal paper, they include findings from several other studies, which also show support for the availability heuristic. Apart from their findings in the "K" study, they also found:

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+---
+title: "Availability heuristic"
+chunk: 2/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+When participants were shown two visual structures and asked to pick the structure that had more paths, participants saw more paths in the structure that had more obvious available paths. In the structure that participants chose, there were more columns and shorter obvious paths, making it more available to them. When participants were asked to complete tasks involving estimation, they would often underestimate the end result. Participants were basing their final estimation on a quick first impression of the problem. Participants particularly struggled when the problems consisted of multiple steps. This occurred because participants were basing their estimation on an initial impression. Participants failed to account for the high rate of growth in the later steps due to the impression they formed in the initial steps. This was shown again in a task that asked participants to estimate the answer to a multiplication task, in which the numbers were presented as either 1x2x3x4x5x6x7x8 or 8x7x6x5x4x3x2x1. Participants who were presented the equation with the larger numbers first (8x7x6...), estimated a significantly higher result than participants with the lower numbers first (1x2x3...). Participants were given a short amount of time to make the estimation, thus participants based their estimates off of what was easily available, which in this case was the first few numbers in the sequence.
+
+== Explanations ==
+Many researchers have attempted to identify the psychological process which creates the availability heuristic.
+Tversky and Kahneman argue that the number of examples recalled from memory is used to infer the frequency with which such instances occur. In an experiment to test this explanation, participants listened to lists of names containing either 19 famous women and 20 less famous men or 19 famous men and 20 less famous women. Subsequently, some participants were asked to recall as many names as possible whereas others were asked to estimate whether male or female names were more frequent on the list. The names of the famous celebrities were recalled more frequently compared to those of the less famous celebrities. The majority of the participants incorrectly judged that the gender associated with more famous names had been presented more often than the gender associated with less famous names. Tversky and Kahneman argue that although the availability heuristic is an effective strategy in many situations when judging probability, use of this heuristic can lead to predictable patterns of errors.
+Schwarz and his colleagues, on the other hand, proposed the ease of retrieval explanation, wherein the ease with which examples come to mind, not the number of examples, is used to infer the frequency of a given class. In a study by Schwarz and colleagues to test their explanation, participants were asked to recall either six or twelve examples of their assertive or very unassertive behavior. Participants were later asked to rate their own assertiveness. Pretesting had indicated that although most participants were capable of generating twelve examples, this was a difficult task. The results indicated that participants rated themselves as more assertive after describing six examples of assertive compared with unassertive behavior, but rated themselves as less assertive after describing twelve examples of assertive compared with unassertive behavior. The study reflected that the extent to which recalled content impacted judgment was determined by the ease with which the content could be brought to mind (it was easier to recall 6 examples than 12), rather than the amount of content brought to mind.
+Research by Vaughn (1999) looked at the effects of uncertainty on the use of the availability heuristic. College students were asked to list either three or eight different study methods they could use in order to get an A on their final exams. The researchers also manipulated the time during the semester they would ask the students to complete the questionnaire.  Approximately half of the participants were asked for their study methods during the third week of classes, and the other half were asked on the last day of classes. Next, participants were asked to rate how likely they would be to get an A in their easiest and hardest classes.  Participants were then asked to rank the difficulty they experienced in recalling the examples they had previously listed. The researchers hypothesized that students would use the availability heuristic, based on the number of study methods they listed, to predict their grade only when asked at the beginning of the semester and about their hardest final. Students were not expected to use the availability heuristic to predict their grades at the end of the semester or about their easiest final. The researchers predicted this use of the availability heuristic because participants would be uncertain about their performance throughout the semester. The results indicated that students used the availability heuristic, based on the ease of recall of the study methods they listed, to predict their performance when asked at the beginning of the semester and about their hardest final. If the student listed only three study methods, they predicted a higher grade at the end of the semester only on their hardest final. If students listed eight study methods, they had a harder time recalling the methods and thus predicted a lower final grade on their hardest final. The results were not seen in the easy final condition because the students were certain they would get an A, regardless of the study method. The results supported this hypothesis and gave evidence to the fact that levels of uncertainty affect the use of the availability heuristic.
+
+== Applications ==

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+---
+title: "Availability heuristic"
+chunk: 3/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+=== Media ===
+After seeing news stories about child abductions, people may judge that the likelihood of this event is greater. Media coverage can help fuel a person's example bias with widespread and extensive coverage of unusual events, such as homicide or airline accidents, and less coverage of more routine, less sensational events, such as common diseases or car accidents. Long term consumption of this media will skew the consumer's reality and influence their attitudes and emotions. This is referred to as cultivation theory, which aligns with availability bias: frequent exposure to similar news stories causes consumers to inflate their sense of how likely these dangers are. For example, when asked to rate the probability of a variety of causes of death, people tend to rate "newsworthy" events as more likely because they can more readily recall an example from memory. Moreover, unusual and vivid events like homicides, shark attacks, or lightning are more often reported in mass media than common and un-sensational causes of death like common diseases.
+For example, many people think that the likelihood of dying from shark attacks is greater than that of dying from being hit by falling airplane parts when more people actually die from falling airplane parts. When a shark attack occurs, the deaths are widely reported in the media whereas deaths as a result of being hit by falling airplane parts are rarely reported in the media. This shows the power media has in priming the social perceiver's thoughts and can lead to the implicit idea that the ocean is more dangerous than flying.
+In a 2010 study exploring how vivid television portrayals are used when forming social reality judgments, people watching vivid violent media gave higher estimates of the prevalence of crime and police immorality in the real world than those not exposed to vivid television. These results suggest that television violence does in fact have a direct causal impact on participants' social reality beliefs. Repeated exposure to vivid violence leads to an increase in people's risk estimates about the prevalence of crime and violence in the real world.  Counter to these findings, researchers from a similar study argued that these effects may be due to effects of new information. Researchers tested the new information effect by showing movies depicting dramatic risk events and measuring their risk assessment after the film. Contrary to previous research, there were no long-term effects on risk perception due to exposure to dramatic movies. However, the study did find evidence of idiosyncratic effects of the movies - that is, people reacted immediately after the movies with enhanced or diminished risk beliefs, which faded after a period of 10 days.
+A similar study in 2024 explored the association between the use of neighbourhood apps and inaccurate perceptions of higher local crime rates. The study expected that, according to cultivation theory, those who consume more crime-related media believe there is a higher risk of being a victim of crime and that media will have a larger impact on heavy vs light users. The study found the largest impact from local news. The study noted that neighbourhood apps may have default enabled push notifications for more frequent and consistent exposure. The conclusions were that the use of neighbourhood apps led to higher perceptions of crimes when controlling for actual crime rates. The constant exposure to crime notifications is theorized to cultivate an availability heuristic that impacts the perception of crime rates. The study noted limitations like an overall small impact and the limits of generalizability by using an opt-in online panel for participants. The limitations bring up that the work is correlational, that it may be possible that those who overestimate local crime rates may be more likely to use the neighbourhood apps because they want to be informed. 
+Another measurable effect is the inaccurate estimation of the fraction of deaths caused by terrorism compared to homicides with other causes.
+In the context of media (often social media), echo chambers need to be considered when discussing availability bias. If a person is constantly exposed to the same perspectives and opinions, they become more engrained and thus more immediately accessible and available when using social media. While conformation bias may perpetuate echo chambers, availability bias can become problematic too as it feeds into this loop.  
+
+=== Health ===
+Researchers examined the role of cognitive heuristics in the AIDS risk-assessment process. 331 physicians reported worry about on-the-job HIV exposure, and experience with patients who have HIV. By analyzing answers to questionnaires handed out, researchers concluded that availability of AIDS information did not relate strongly to perceived risk.
+Participants in a 1992 study read case descriptions of hypothetical patients who varied on their sex and sexual preference. These hypothetical patients showed symptoms that could have been caused by five different diseases (AIDS, leukemia, influenza, meningitis, or appendicitis). Participants were instructed to indicate which disease they thought the patient had and then they rated patient responsibility and interaction desirability. Consistent with the availability heuristic, either the more common (influenza) or the more publicized (AIDS) disease was chosen.
+
+=== Business and economy ===
+One study sought to analyze the role of the availability heuristic in financial markets. Researchers defined and tested two aspects of the availability heuristic:

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+---
+title: "Availability heuristic"
+chunk: 4/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+Outcome Availability – availability of positive and negative investment outcomes, and
+Risk Availability – availability of financial risk.
+On days of substantial stock market moves, abnormal stock price reactions to upgrades are weaker, than those to downgrades. These availability effects are still significant even after controlling for event-specific and company-specific factors.
+Similarly, research has pointed out that under the availability heuristic, humans are not reliable because they assess probabilities by giving more weight to current or easily recalled information instead of processing all relevant information. Since information regarding the current state of the economy is readily available, researchers attempted to expose the properties of business cycles to predict the availability bias in analysts' growth forecasts. They showed the availability heuristic to play a role in analysis of forecasts and influence investments because of this.
+In effect, investors are using the availability heuristic to make decisions and subsequently, may be obstructing their own investment success. An investor's lingering perceptions of a dire market environment may be causing them to view investment opportunities through an overly negative lens, making it less appealing to consider taking on investment risk, no matter how small the returns on perceived "safe" investments.  To illustrate, Franklin Templeton's annual Global Investor Sentiment Survey 1 asked individuals how they believed the S&P 500 Index performed in 2009, 2010, and 2011. 66 percent of respondents stated that they believed the market was either flat or down in 2009, 48 percent said the same about 2010 and 53 percent also said the same about 2011.  In reality, the S&P 500 saw 26.5 percent annual returns in 2009, 15.1 percent annual returns in 2010, and 2.1 percent annual returns in 2011, meaning lingering perceptions based on dramatic, painful events are impacting decision-making even when those events are over.
+Additionally, a study by Hayibor and Wasieleski found that the availability of others who believe that a particular act is morally acceptable is positively related to others' perceptions of the morality of that act. This suggests that availability heuristic also has an effect on ethical decision making and ethical behavior in organizations.
+
+=== Education ===
+A study done by Craig R. Fox provides an example of how availability heuristics can work in the classroom. In this study, Fox tests whether the difficulty of recall influences judgment, specifically with course evaluations among college students.  In his study he had two groups complete a course evaluation form.  He asked the first group to write two recommended improvements for the course (a relatively easy task) and then write two positives about the class. The second group was asked to write ten suggestions where the professor could improve (a relatively difficult task) and then write two positive comments about the course.  At the end of the evaluation, both groups were asked to rate the course on a scale from one to seven.  The results showed that students asked to write ten suggestions (difficult task) rated the course less harshly because it was more difficult for them to recall the information. Most of the students in the group that was asked to fill in 10 suggestions didn't fill in more than two being unable to recall more instances where they were unsatisfied with the class. Students asked to do the easier evaluation with only two complaints had less difficulty in terms of availability of information, so they rated the course more harshly.
+Another study by Marie Geurten sought to test the availability heuristic in young children. Children of varying ages (from 4 to 8 years old) were tasked with generating a list of names, with some being asked for a shorter list and some for a longer list. The study then assessed the children's own impressions of their ability to recall names. Those children who were tasked with generating a shorter list had a higher perception of their ability to recall names than those who were tasked with generating a longer list. According to the study, this suggests that the children based their assessment of their recall abilities on their subjective experience of ease of recall.

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+title: "Availability heuristic"
+chunk: 5/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+=== Criminal justice ===
+The media usually focuses on violent or extreme cases, which are more readily available in the public's mind. This may come into play when it is time for the judicial system to evaluate and determine the proper punishment for a crime. In one study, respondents rated how much they agreed with hypothetical laws and policies such as "Would you support a law that required all offenders convicted of unarmed muggings to serve a minimum prison term of two years?" Participants then read cases and rated each case on several questions about punishment. As hypothesized, respondents recalled more easily from long-term memory stories that contain severe harm, which seemed to influence their sentencing choices to make them push for harsher punishments. This can be eliminated by adding high concrete or high contextually distinct details into the crime stories about less severe injuries.
+A similar study asked jurors and college students to choose sentences on four severe criminal cases in which prison was a possible but not an inevitable sentencing outcome. Respondents answering questions about court performance on a public opinion formulated a picture of what the courts do and then evaluated the appropriateness of that behavior. Respondents recalled public information about crime and sentencing. This type of information is incomplete because the news media present a highly selective and non-representative selection of crime, focusing on the violent and extreme, rather than the ordinary. This makes most people think that judges are too lenient. But, when asked to choose the punishments, the sentences given by students were equal to or less severe than those given by judges. In other words, the availability heuristic made people believe that judges and jurors were too lenient in the courtroom, but the participants gave similar sentences when placed in the position of the judge, suggesting that the information they recalled was not correct.
+Researchers in 1989 predicted that mock jurors would rate a witness to be more deceptive if the witness testified truthfully before lying than when the witness was caught lying first before telling the truth. If the availability heuristic played a role in this, lying second would remain in jurors' minds (since it was more recent) and they would most likely remember the witness lying over the truthfulness. To test the hypothesis, 312 university students played the roles of mock jurors and watched a videotape of a witness presenting testimony during a trial. Results confirmed the hypothesis, as mock jurors were most influenced by the most recent act.
+
+=== Perceived risk ===
+
+Previous studies have indicated that explaining a hypothetical event makes the event seem more likely through the creation of causal connections. However, such effects could arise through the use of the availability heuristic; that is, subjective likelihood is increased by an event becoming easier to imagine.
+A study done asked those participating to pick between two illnesses. Those doing the study wanted to know which disease they thought was more likely to cause death. In the study, they asked participants to choose between a stroke and asthma as to which one someone was more likely to die from. The researchers concluded that it depended on what experiences were available to them. If they knew someone or heard of someone that died from one of the diseases that is the one they perceived to be a higher risk to die from.
+
+=== Vividness effects ===
+Two studies with 108 undergraduates investigated vivid information and its impact on social judgment and the availability heuristic and its role in mediating vividness effects.
+In study 1, Subjects listened to a tape recording that described a woman who lived with her 7-year-old son. Subjects then heard arguments about the woman's fitness as a parent and were asked to draw their own conclusions regarding her fitness or unfitness. The concrete and colorful language were found to influence judgments about the woman's fitness as a mother.
+In study 2, a series of male and female names were presented to subjects; for each name, subjects were told the university affiliation of the individual (Yale or Stanford). When some names were presented, subjects were simultaneously shown a photograph that purportedly portrayed the named individual. Subsequently, to assess what subjects could remember (as a measure of availability), each name was represented, as well as the appropriate photograph if one had been originally presented. The study considered whether the display or non-display of photographs biased subjects' estimates as to the percentage of Yale (vs Stanford) students in the sample of men and women whose names appeared on the original list, and whether these estimated percentages were causally related to the respondents' memory for the college affiliations of the individual students on the list. The presence of photographs affected judgments about the proportion of male and female students at the two universities. Such effects have typically been attributed to the ready accessibility of vividly presented information in memory—that is, to the availability heuristic.
+In both studies, vividness affected both availability (ability to recall) and judgments. However, causal modeling results indicated that the availability heuristic did not play a role in the judgment process.

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+---
+title: "Availability heuristic"
+chunk: 6/6
+source: "https://en.wikipedia.org/wiki/Availability_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:20.549400+00:00"
+instance: "kb-cron"
+---
+
+=== Judging frequency and probability ===
+In general, availability is correlated with ecological frequency, but it is also affected by other factors. Consequently, the reliance on the availability heuristic leads to systematic biases. Such biases are demonstrated in the judged frequency of classes of words, of combinatoric outcomes, and of repeated events. The phenomenon of illusory correlation is explained as an availability bias.
+In the original Tversky and Kahneman (1973) research, three major factors that are discussed are the frequency of repetition, frequency of co-occurrence, and illusory correlation. The use of frequency of repetition aids in the retrieval of relevant instances. The idea behind this phenomenon is that the more an instance is repeated within a category or list, the stronger the link between the two instances becomes. Individuals then use the strong association between the instances to determine the frequency of an instance. Consequently, the association between the category or list and the specific instance often influences frequency judgement. Frequency of co-occurrence strongly relates to Frequency of repetition, such that the more an item-pair is repeated, the stronger the association between the two items becomes, leading to a bias when estimating the frequency of co-occurrence. Due to the phenomena of frequency of co-occurrence, illusory correlations also often play a big role.
+Another factor that affects the availability heuristic in frequency and probability is exemplars. Exemplars are the typical examples that stand out during the process of recall. If asked what participants thought different set sizes were (how many men and how many women are in the class), participants would use exemplars to determine the size of each set.  Participants would derive their answers on ease of recall of the names that stood out. Participants read a list of names of members of a class for 30 seconds, and then participants were asked the male to female ratio of the class. The participant's answer would depend on the recall of exemplars. If the participant reading the list recalled seeing more common male names, such as Jack, but the only female names in the class were uncommon names, such as Deepika, then the participant will recall that there were more men than women. The opposite would be true if there were more common female names on the list and uncommon male names. Due to the availability heuristic, names that are more easily available are more likely to be recalled, and can thus alter judgments of probability.
+Another example of the availability heuristic and exemplars would be seeing a shark in the ocean. Seeing a shark has a greater impact on an individual's memory than seeing a dolphin.  If someone sees both sharks and dolphins in the ocean, they will be less aware of seeing the dolphins, because the dolphins had less of an impact on their memory. Due to the greater impact of seeing a shark, the availability heuristic can influence the probability judgement of the ratio of sharks and dolphins in the water. Thus, an individual who saw both a shark and a dolphin would assume a higher ratio of sharks in the water, even if there are more dolphins in reality.
+
+== Critiques ==
+
+=== Ease of recall as a critique ===
+One of the earliest and most powerful critiques of the original Tversky and Kahneman study on the availability heuristic was the Schwarz et al. study which found that the ease of recall was a key component in determining whether a concept became available.  Many studies since this criticism of the original availability heuristic model have repeated this initial criticism, that the ease of recall factor became an integral facet of the availability heuristic itself (see Research section).
+
+=== Alternative explanations ===
+Much of the criticism against the availability heuristic has claimed that making use of the content that becomes available in our mind is not based on the ease of recall as suggested by Schwarz et al.  For example, it could be argued that recalling more words that begin with K than words with the third letter being K could arise from how we categorize and process words into our memory.  If we categorize words by the first letter and recall them through the same process, this would show more support for the representative heuristic than the availability heuristic.  Based on the possibility of explanations such as these, some researchers have claimed that the classic studies on the availability heuristic are too vague in that they fail to account for people's underlying mental processes.  Indeed, a study conducted by Wanke et al. demonstrated this scenario can occur in situations used to test the availability heuristic.
+A second line of study has shown that frequency estimation may not be the only strategy we use when making frequency judgments.  A recent line of research has shown that our situational working memory can access long-term memories, and this memory retrieval process includes the ability to determine more accurate probabilities.
+
+== See also ==
+
+Anomic aphasia
+Attribute substitution
+Cache language model
+Confirmation bias
+Gambler's fallacy
+List of cognitive biases
+Recency bias
+Streetlight effect
+
+== References ==
+
+== External links ==
+How Belief Works – an article on the origins of the availability bias.

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+---
+title: "Babble hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Babble_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:03.879807+00:00"
+instance: "kb-cron"
+---
+
+In psycholinguistics and leadership studies, the babble hypothesis (demonstratively labelled the babble effect) is a conjecture that posits a strong correlation between the amount or quantity of speaking time an individual has in group settings and their likelihood of emerging as a leader, as commonly opposed to quality of speech. According to the hypothesis, individuals who contribute more verbal input during group interactions are perceived to have increased speaking time which in turn increases likelihood of them being perceived and recognized as leaders. Those individuals who speak more also receive higher ratings on leader, communication and contribution-related measures.
+
+
+== Past research ==
+Research into the idea that emerging leaders talk a lot has been around for a long time, with Bales making this claim in 1950. One of the earliest studies that directly varied the quality and quantity of verbal interaction was by Regula and Julian (1973). They found that variations in the quantity but not in the quality of task contributions affected whether the power to influence others was attributed to an individual.
+There have since been many studies investigating the extent to which speaking time can predict the emergence of leaders in previously leaderless groups. However, many have been either ecologically invalid or used approaches to data collection and analysis techniques that were not comprehensive enough to produce applicable results, namely Riecken (1958), Jaffee and Lucas (1969), and Bavelas, Hastorf, Gross and Kite (1965). 
+After examining the flaws of previous research, McLaren et al. attempted to address these weaknesses in their own study. In it, diverse groups of participants were observed in challenging strategy games, with measurement of both speaking time and the substance of their utterances. The study confirmed that speaking time had the highest correlation with leadership emergence, surpassing other factors such as intelligence, agreeableness, and game proficiency. 
+Although the quality of what an individual was saying was not found to have a significant influence, the physical behaviours associated with individuals' speaking time seemed important in their emergence as leaders. This included counts of eye fixation and vocal pitch. Further research shows speaking time and seating position both emerged as significant predictors of more visual attention, which individuals pay more to their perceived leaders. Speaking time was also positively correlated to judges' perceptions of dominance. Dominance is a key quality of leaders, as theories of followership claim people favour dominant leaders in order to enhance their ability to aggress against out-groups.
+The study also noted the secondary influence of gender. Gender was found to influence both production and interpretation of speaking time, consistent with the expectation states theory. This theory predicts that in groups that vary in external status markers, such as gender, age and intelligence, the markers become predictors of within-group status through both direct, including voting behaviour, and indirect pathways like speaking time.
+
+
+== The impact of gender differences ==
+The reason for underrepresentation of women in emerging leadership positions can be explained by objective speaking time differences. Equal speaking times are thought to narrow the leadership emergence gender gap. There does not seem to be a correlation with gender differences in leader effectiveness. A follow-up study however found no significant effects for gender when predicting leader emergence or in the amount of time that women and men spoke. This reinforces the idea that speaking time has a larger influence on leadership emergence than the qualities and identity the emerging leader may have.
+Changing stereotypes about women and their role in society have allowed women to become more agentic, and this trait has been hypothesised to have a positive relationship with participation. Participation, consistent with the babble hypothesis, increases the likelihood of leader emergence by increasing the prominence a group member has within their group.
+Other variables have been found, however, that result in women being less likely to emerge as leaders. Examples of these include the group's cultural background (less egalitarian cultural groups are less likely to have women emerge as leaders) and the amount of time spent interacting with a possible emerging leader (gender differences were found to be attenuated when raters had a larger length of time or multiple occasions to make their judgement on whether someone is an adequate leader). Nevertheless, increased time spent may increase an individual's perceived speaking time and this may be the reason for the leader emergence.
+
+
+== Criticisms and conclusions ==
+Group members seem to regulate the speaking time of other members; suggesting that speaking time may be a result of group processes and perceptions (Bass, 1990). He argued for a dichotomy of quality and quantity of speech.
+Furthermore, a 2011 study found that certain personality traits, such as authoritarianism, creativity, extraversion and intelligence, predicted who would emerge as a leader in a previously leaderless group. These, consistently with Bass' theory, will be reflected by the quality of what an emerging leader is saying. Although it may be argued one with more speaking time will have more opportunity to display these personality traits, this research suggests a combination of quality and speaking time will predict leader emergence rather than speaking time alone, challenging the babble hypothesis.
+Furthermore, the idea that leadership emergence does not depend on the identity of emerging leaders goes against the social categorisation theory of leadership. Social identity theory states that individuals develop their social identity based on their unique characteristics and their affiliation with a social group, namely their shared experiences with others in the group (Tajfel & Turner (1986)). The social categorisation theory of leadership suggests that people who internalise the identity of the group, and make it part of their social identity, are more likely to emerge as leaders. Leader emergence therefore occurs according to the group prototype, which is the group members' shared representation of their group, including its norms, values, beliefs, and aspirations. This links to both the expectations that members of a group have for their leader and the quality of their leadership, rather than only their speaking time. 
+Although speaking time may be an accurate predictor of leadership emergence, there are other factors that can impact the extent of the accuracy of predictions based on the babble hypothesis, as many other elements such as gender and expectations can play a role in individuals' perceptions of adequate leaders.
+
+
+== See also ==
+Agitprop
+Active measures
+Big lie
+Cult of personality
+Firehose of falsehood
+Gish gallop
+Peter principle
+
+
+== References ==

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+---
+title: "Balance of angular momentum"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Balance_of_angular_momentum"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:14.393868+00:00"
+instance: "kb-cron"
+---
+
+In classical mechanics, the balance of angular momentum, also known as Euler's second law, is a fundamental law of physics stating that a torque (a twisting force that causes rotation) must be applied to change the angular momentum (a measure of rotational motion) of a body. This principle, distinct from Newton's laws of motion, governs rotational dynamics. For example, to spin a playground merry-go-round, a push is needed to increase its angular momentum, while friction in the bearings and drag create opposing forces that slowly reduce it, eventually stopping the motion.
+
+First articulated by Swiss mathematician and physicist Leonhard Euler in 1775, the balance of angular momentum is a cornerstone of physics with broad applications. It implies the equality of corresponding shear stresses and the symmetry of the Cauchy stress tensor in continuum mechanics, a result also consistent with the Boltzmann Axiom, which posits that internal forces in a continuum are torque-free. These concepts—the balance of angular momentum, the symmetry of the Cauchy stress tensor, and the Boltzmann Axiom—are interconnected, as the former provides a physical basis for the latter two in continuum mechanics. It is also vital for analyzing systems like the spinning top, determining the skew-symmetric part of the stress tensor, and understanding the gyroscopic effect linked to the D'Alembert force.
+
+== Mathematical definition ==
+The mathematical formulation states that the rate of change 
+  
+    
+      
+        
+          
+            
+              
+                
+                  
+                    L
+                    →
+                  
+                
+                ˙
+              
+            
+          
+          
+            c
+          
+        
+      
+    
+    {\displaystyle {\dot {\vec {L}}}_{c}}
+  
+ of angular momentum 
+  
+    
+      
+        
+          
+            
+              
+                L
+                →
+              
+            
+          
+          
+            c
+          
+        
+      
+    
+    {\displaystyle {\vec {L}}_{c}}
+  
+ about a point 
+  
+    
+      
+        
+          
+            
+              c
+              →
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {c}}}
+  
+, is equal to the sum of the external torques 
+  
+    
+      
+        
+          
+            
+              
+                M
+                →
+              
+            
+          
+          
+            c
+          
+        
+      
+    
+    {\displaystyle {\vec {M}}_{c}}
+  
+ acting on that body about that point:
+
+  
+    
+      
+        
+          
+            
+              
+                M
+                →
+              
+            
+          
+          
+            c
+          
+        
+        =
+        
+          
+            
+              
+                
+                  
+                    L
+                    →
+                  
+                
+                ˙
+              
+            
+          
+          
+            c
+          
+        
+      
+    
+    {\displaystyle {\vec {M}}_{c}={\dot {\vec {L}}}_{c}}
+  
+
+The point 
+  
+    
+      
+        
+          
+            
+              c
+              →
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {c}}}
+  
+ is a fixed point in an inertial system or the center of mass of the body. In the special case, when external torques vanish, it shows that the angular momentum is preserved. The d'Alembert force counteracting the change of angular momentum shows as a gyroscopic effect.
+
+== History ==
+Swiss mathematician Jakob I Bernoulli applied the balance of angular momentum in 1703 – without explicitly formulating it – to find the center of oscillation of a pendulum, which he had already done in a first, somewhat incorrect manner in 1686. The balance of angular momentum thus preceded Newton's laws, which were first published in 1687.
+In 1744, Euler was the first to use the principles of momentum and of angular momentum to state the equations of motion of a system. In 1750, in his treatise "Discovery of a new principle of mechanics" he published the Euler's equations of rigid body dynamics, which today are derived from the balance of angular momentum, which Euler, however, could deduce for the rigid body from Newton's second law. After studies on plane elastic continua, which are indispensable to the balance of the torques, Euler raised the balance of angular momentum to an independent principle for calculation of the movement of bodies in 1775.
+In 1822, French mathematician Augustin-Louis Cauchy introduced the stress tensor whose symmetry in combination with the balance of linear momentum made sure the fulfillment of the balance of angular momentum in the general case of the deformable body. The interpretation 
+  
+    
+      
+        
+          
+            
+              M
+              →
+            
+          
+        
+        =
+        
+          
+            
+              
+                
+                  L
+                  →
+                
+              
+              ˙
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {M}}={\dot {\vec {L}}}}
+  
+ of the balance of angular momentum was first noted by M. P. Saint-Guilhem in 1851.
+
+== Kinetics of rotation ==
+Kinetics deals with states that are not in mechanical equilibrium. According to Newton's second law, an external force leads to a change in velocity (acceleration) of a body. Analogously an external torque means a change in angular velocity resulting in an angular acceleration. The inertia relating to rotation depends not only on the mass of a body but also on its spatial distribution. With a rigid body this is expressed by the moment of inertia. With a rotation around a fixed axis, the torque is proportional to the angular acceleration with the moment of inertia as proportionality factor. Here the moment of inertia is not only dependent on the position of the axis of rotation (see Steiner Theorem) but also on its direction. Should the above law be formulated more generally for any axis of rotation then the inertia tensor must be used.
+With the two-dimensional special case, a torque only results in an acceleration or slowing down of a rotation. With the general three-dimensional case, however, it can also alter the direction of the axis (precession).
+
+== Formulations ==
+In rigid body dynamics the balance of angular momentum leads to Euler's equations.
+In continuum mechanics the balance of angular momentum leads to Cauchy's second law of motion, that states the symmetry of the Cauchy stress tensor. The Boltzmann Axiom has the same consequence.
+
+== Boltzmann Axiom ==
+
+In 1905, Austrian physicist Ludwig Boltzmann pointed out that with reduction of a body into infinitesimally smaller volume elements, the inner reactions have to meet all static conditions for mechanical equilibrium. Cauchy's stress theorem handles the equilibrium in terms of force. For the analogous statement in terms of torque, German mathematician Georg Hamel coined the name Boltzmann Axiom.
+This axiom is equivalent to the symmetry of the Cauchy stress tensor. For the resultants of the stresses do not exert a torque on the volume element, the resultant force must lead through the center of the volume element. The line of action of the inertia forces and the normal stress resultants σxx·dy and σyy·dx lead through the center of the volume element. In order that the shear stress resultants τxy·dy and τyx·dx lead through the center of the volume element
+
+  
+    
+      
+        
+          
+            
+              
+                τ
+                
+                  x
+                  y
+                
+              
+              
+                d
+              
+              y
+            
+            
+              
+                τ
+                
+                  y
+                  x
+                
+              
+              
+                d
+              
+              x
+            
+          
+        
+        =
+        
+          
+            
+              
+                d
+              
+              y
+            
+            
+              
+                d
+              
+              x
+            
+          
+        
+        
+        →
+        
+        
+          τ
+          
+            y
+            x
+          
+        
+        =
+        
+          τ
+          
+            x
+            y
+          
+        
+      
+    
+    {\displaystyle {\frac {\tau _{xy}\mathrm {d} y}{\tau _{yx}\mathrm {d} x}}={\frac {\mathrm {d} y}{\mathrm {d} x}}\quad \rightarrow \quad \tau _{yx}=\tau _{xy}}
+  

data/en.wikipedia.org/wiki/Balance_of_angular_momentum-1.md

@@ -0,0 +1,362 @@
+---
+title: "Balance of angular momentum"
+chunk: 2/2
+source: "https://en.wikipedia.org/wiki/Balance_of_angular_momentum"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T10:01:14.393868+00:00"
+instance: "kb-cron"
+---
+
+must hold. This is actually the statement of the equality of corresponding shear stresses in the xy plane.
+
+== Cosserat Continuum ==
+In addition to the torque-free classical continuum with a symmetric stress tensor, cosserat continua (polar continua) that are not torque-free have also been defined. One application of such a continuum is the theory of shells. Cosserat continua are not only capable to transport a momentum flux but also an angular momentum flux. Therefore, there also may be sources of momentum and angular momentum inside the body. Here the Boltzmann Axiom does not apply and the stress tensor may be skew-symmetric.
+If these fluxes are treated as usual in continuum mechanics, field equations arise in which the skew-symmetric part of the stress tensor has no energetic significance. The balance of angular momentum becomes independent of the balance of energy and is used to determine the skew-symmetric part of the stress tensor. American mathematician Clifford Truesdell saw in this the "true basic sense of Euler's second law".
+
+== Area rule ==
+
+The area rule is a corollary of the angular momentum law in the form: The resulting moment is equal to the product of twice the mass and the time derivative of the areal velocity.
+It refers to the ray 
+  
+    
+      
+        
+          
+            
+              r
+              →
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {r}}}
+  
+ to a point mass with mass m. This has the angular momentum with the velocity 
+  
+    
+      
+        
+          
+            
+              
+                
+                  r
+                  →
+                
+              
+              ˙
+            
+          
+        
+      
+    
+    {\displaystyle {\dot {\vec {r}}}}
+  
+ and the momentum 
+  
+    
+      
+        
+          
+            
+              p
+              →
+            
+          
+        
+        =
+        m
+        
+          
+            
+              
+                
+                  r
+                  →
+                
+              
+              ˙
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {p}}=m{\dot {\vec {r}}}}
+  
+
+  
+    
+      
+        
+          
+            
+              L
+              →
+            
+          
+        
+        =
+        
+          
+            
+              r
+              →
+            
+          
+        
+        ×
+        
+          
+            
+              p
+              →
+            
+          
+        
+        =
+        m
+        
+          
+            
+              r
+              →
+            
+          
+        
+        ×
+        
+          
+            
+              
+                
+                  r
+                  →
+                
+              
+              ˙
+            
+          
+        
+        =
+        m
+        
+          
+            
+              r
+              →
+            
+          
+        
+        ×
+        
+          d
+        
+        
+          
+            
+              r
+              →
+            
+          
+        
+        
+          /
+        
+        
+          d
+        
+        t
+      
+    
+    {\displaystyle {\vec {L}}={\vec {r}}\times {\vec {p}}=m{\vec {r}}\times {\dot {\vec {r}}}=m{\vec {r}}\times \mathrm {d} {\vec {r}}/\mathrm {d} t}
+  
+.
+In the infinitesimal time dt the trajectory sweeps over a triangle whose content is 
+  
+    
+      
+        
+          d
+        
+        
+          
+            
+              A
+              →
+            
+          
+        
+        =
+        
+          
+            
+              1
+              2
+            
+          
+        
+        
+          
+            
+              r
+              →
+            
+          
+        
+        ×
+        
+          d
+        
+        
+          
+            
+              r
+              →
+            
+          
+        
+      
+    
+    {\displaystyle \mathrm {d} {\vec {A}}={\tfrac {1}{2}}{\vec {r}}\times \mathrm {d} {\vec {r}}}
+  
+, see image, areal velocity and cross product "×". This is how it turns out:
+
+  
+    
+      
+        
+          
+            
+              L
+              →
+            
+          
+        
+        =
+        m
+        
+          
+            
+              r
+              →
+            
+          
+        
+        ×
+        
+          d
+        
+        
+          
+            
+              r
+              →
+            
+          
+        
+        
+          /
+        
+        
+          d
+        
+        t
+        =
+        2
+        m
+        
+        
+          d
+        
+        
+          
+            
+              A
+              →
+            
+          
+        
+        
+          /
+        
+        
+          d
+        
+        t
+        =
+        2
+        m
+        
+          
+            
+              
+                
+                  A
+                  →
+                
+              
+              ˙
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {L}}=m{\vec {r}}\times \mathrm {d} {\vec {r}}/\mathrm {d} t=2m\,\mathrm {d} {\vec {A}}/\mathrm {d} t=2m{\dot {\vec {A}}}}
+  
+.
+With Euler's second law this becomes:
+
+  
+    
+      
+        
+          
+            
+              M
+              →
+            
+          
+        
+        =
+        
+          
+            
+              
+                
+                  L
+                  →
+                
+              
+              ˙
+            
+          
+        
+        =
+        2
+        m
+        
+          
+            
+              
+                
+                  A
+                  →
+                
+              
+              ¨
+            
+          
+        
+      
+    
+    {\displaystyle {\vec {M}}={\dot {\vec {L}}}=2m{\ddot {\vec {A}}}}
+  
+.
+The special case of plane, moment-free central force motion is treated by Kepler's second law, also known as the area rule.
+
+== See also ==
+Conservation of angular momentum
+
+== References ==

data/en.wikipedia.org/wiki/Berserker_hypothesis-0.md

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+---
+title: "Berserker hypothesis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Berserker_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:05.161026+00:00"
+instance: "kb-cron"
+---
+
+The Berserker hypothesis, also known as the deadly probes scenario, is the idea that humans have not yet detected intelligent alien life in the universe because it has been systematically destroyed by a series of lethal Von Neumann probes. The hypothesis is named after the Berserker series of novels (1963–2005) written by Fred Saberhagen.
+The hypothesis has no single known proposer, and instead is thought to have emerged over time in response to the Hart–Tipler conjecture, the idea that an absence of detectable Von Neumann probes is contrapositive evidence that no intelligent life exists outside of the Solar System. According to the Berserker hypothesis, an absence of such probes is not evidence of life's absence, since interstellar probes could "go berserk" and destroy other civilizations, before self-destructing.
+In his 1983 paper "The Great Silence", astronomer David Brin summarized the implications of the Berserker hypothesis: it is entirely compatible with all the facts and logic of the Fermi paradox, but would mean that there exists no intelligent life left to be discovered. In the worst case, humanity has already alerted others to its  existence, and is next in line to be destroyed.
+
+There is no need to struggle to suppress the elements of the Drake equation in order to explain the Great Silence, nor need we suggest that no [intelligent aliens] anywhere would bear the cost of interstellar travel. It need only happen once for the results of this scenario to become the equilibrium conditions in the Galaxy. We would not have detected extra-terrestrial radio traffic – nor would any [intelligent aliens] have ever settled on Earth – because all were killed shortly after discovering radio.
+
+
+== Background ==
+
+There is no reliable or reproducible evidence that aliens have visited Earth. No transmissions or evidence of intelligent life have been observed anywhere other than Earth in the Universe. This runs counter to the knowledge that the Universe is filled with a very large number of planets, some of which likely hold the conditions hospitable for life. Life typically expands until it fills all available niches. These contradictory facts form the basis for the Fermi paradox, of which the Berserker hypothesis is one proposed solution.
+
+
+=== Sentinel type Berserker ===
+In his science fiction novel "The Sentinel", Arthur C. Clarke propose that instead of an advanced civilisation sending a berserker to seek and destroy cosmic civilisations as they emerge past a given stage of development, a sentinel is placed in the vicinity of an emerging civilisation, passively waiting to be discovered by it, once this watched civilisation reaches the specific stage of development that allows it to reach and find it.
+In this approach, the placement of the sentinel would determine the target stage at which emerging civilisations should be eliminated; a moon of the home planet, a near-by planet, the edge of the solar system, or the nearest solar system, all entail different levels of technological advancement that the watched civilisation must reach before the sentinel is activated.
+
+
+== Responses ==
+A key component of the hypothesis is that Earth's solar system has not yet been visited by a Berserker probe. In a 2013 analysis by Anders Sandberg and Stuart Armstrong at the Future of Humanity Institute at University of Oxford, they predicted that even a slowly replicated set of Berserker probes, if it were able to destroy civilizations elsewhere, would also very likely have already encountered (and destroyed) humanity.
+
+
+== Relationship to other proposed Fermi paradox solutions ==
+The Berserker hypothesis is distinct from the dark forest hypothesis in that under the latter, many alien civilizations could still exist provided they keep silent. The dark forest hypothesis can be viewed as a special case of the Berserker hypothesis, if the 'deadly Berserker probes' are (e.g. due to resource scarcity) only sent to star systems that show signs of intelligent life. 
+The Great Filter hypothesis is a more general counterpart to the Berserker hypothesis, which posits that a great event or barrier prevents early-stage extraterrestrial life from developing into intelligent space-faring civilizations. In the Berserker hypothesis framing, the filter would exist between the industrial age and widespread space colonization.
+
+
+== References ==

data/en.wikipedia.org/wiki/Biophilia_hypothesis-0.md

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+---
+title: "Biophilia hypothesis"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Biophilia_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:06.376743+00:00"
+instance: "kb-cron"
+---
+
+The biophilia hypothesis (also called BET) suggests that humans possess an innate tendency to seek connections with nature and other forms of life. Edward O. Wilson introduced and popularized the hypothesis in his book, Biophilia (1984). He defines biophilia as the "innate tendency to focus on life and lifelike processes". He argued that "to explore and affiliate with life is a deep and complicated process in mental development. To an extent still undervalued in philosophy and religion, our existence depends on this propensity, our spirit is woven from it, hope rises on its currents". Wilson saw modern biology as converging with biophilia: "Modern biology has produced a genuinely new way of looking at the world that is incidentally congenial to the inner direction of biophilia. In other words, instinct is in this rare instance aligned with reason.... to the degree that we come to understand other organisms, we will place a greater value on them, and on ourselves".
+
+== Natural affinity for living systems ==
+"Biophilia" is an innate affinity of life or living systems. The term was first used by Erich Fromm to describe a psychological orientation of being attracted to all that is alive and vital. Wilson uses the term  in a related sense when he suggests that biophilia describes "the connections that human beings subconsciously seek with the rest of life." He proposed the possibility that the deep affiliations humans have with other life forms and nature as a whole are rooted in our biology. Both positive and negative (including phobic) affiliations toward natural objects (species, phenomenon) as compared to artificial objects are evidence for biophilia.
+Although named by Fromm, the concept of biophilia has been proposed and defined many times over. Aristotle was one of many to put forward a concept that could be summarized as "love of life". Diving into the term philia, or friendship, Aristotle evokes the idea of reciprocity and how friendships are beneficial to both parties in more than just one way, but especially in the way of happiness.
+The hypothesis has since been developed as part of theories of evolutionary psychology. Taking on an evolutionary perspective, people being drawn towards life and nature can be explained in part due to our evolutionary history of residing in natural environments, as only recently in our history have we shifted towards an urbanized lifestyle. These connections to nature can still be seen in people today as people gravitate towards, identify with, and desire to connect with nature. These connections are not limited to any one component part of nature, as people show connections to a wide range of natural things including plants, animals, and environmental landscapes. One possible explanation is that our ancestors who had stronger connections to nature would hold an evolutionary advantage over less connected people as they would have better knowledge and therefore access to food, water, and shelter. In a broader and more general sense research has suggested that our modern urban environments are not suited for minds that evolved in natural environments.
+Human preferences toward things in nature, while refined through experience and culture, are hypothetically the product of biological evolution. For example, adult mammals (especially humans) are generally attracted to baby mammal faces with their large eyes and rounded features and find them appealing across species. Similarly, the hypothesis helps explain why ordinary people care for and sometimes risk their lives to save domestic and wild animals, and keep plants and flowers in and around their homes. In the book Children and Nature: Psychological, Sociocultural, and Evolutionary Investigations edited by Peter Kahn and Stephen Kellert, the importance of animals, especially those with which a child can develop a nurturing relationship, is emphasized particularly for early and middle childhood. The same book reports on the help that animals can provide to children with autistic-spectrum disorders.
+
+=== Physiological responses: fractal fluency ===
+Fractal fluency is a neuroscience model that proposes that, through exposure to nature's fractal scenery, people's visual systems have adapted to efficiently process fractals with ease. Fractals are patterns that repeat at different scales. Examples in natural scenery include clouds, mountains and trees. This adaptation to fractal patterns occurs at many stages of the visual system, from the way people's eyes move to which regions of the brain get activated. Fluency puts the viewer in a ‘comfort zone’ so inducing an aesthetic experience. Humans appear to be especially well-adapted to processing fractal patterns with fractal dimension between 1.3 and 1.5. When humans view fractal patterns with fractal dimensions in this range, these fractals reduce physiological stress and boost cognitive abilities.
+Biophilic fractals are patterns designed to induce the health and well-being benefits associated with exposure to nature's scenery. These include stress-reduction and enhanced cognitive capacity. Designers and architects incorporate biophilic fractals into the built environment to counter the fact that people spend 92% of their time indoors and away from nature's scenery. The Fractal Chapel designed by INNOCAD architecture in the state hospital in Graz, Austria, is a prominent example and recipient of the 2025 IIDA (International Interior Design Association) Best of Competition Award.
+
+== Indigenous perspectives on the human-nature connection ==

data/en.wikipedia.org/wiki/Biophilia_hypothesis-1.md

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+---
+title: "Biophilia hypothesis"
+chunk: 2/2
+source: "https://en.wikipedia.org/wiki/Biophilia_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:06.376743+00:00"
+instance: "kb-cron"
+---
+
+Many Indigenous cultures do not draw a sharp distinction between humans and nature. In these traditions, humans may be understood as an integral part of the natural world rather than as separate from it. Human practices and ways of life may be seen to be based in relationships of reciprocity involving all living beings and the environment.
+At the heart of such belief systems is the concept of kinship, which extends beyond human relationships and includes elements of the natural world. Humans, other animals, plants and soil are seen as dependent on each other for survival and health. For example, the Haudenosaunee people express this idea through a "Thanksgiving Address", a ceremony intended to honor all aspects of nature.
+Some Indigenous cultures have developed what has been referred to as "traditional ecological knowledge". This may include ostensibly sustainable stewardship practices such as controlled burns of vegetation, as employed in some traditional Native American and Aboriginal Australian societies. In Hawaii, the idea of Aloha_ʻĀina aloha has served as a guide for responsible resource use.
+Indigenous and animist beliefs typically view nature as sacred. Specific sites, species, or phenomena holding deep significance. Emphasis is put on objectives such as reciprocity and balance. This may imply an idea of nature restoration through sustainable practices, rituals, and ceremonies. For instance, the Anishinaabe make offerings before harvesting wild rice.
+
+== Biophilic design ==
+In architecture, biophilic design is a sustainable design strategy that incorporates reconnecting people with the natural environment. It may be seen as a necessary complement to green architecture, which decreases the environmental impact of the built world but does not address human reconnection with the natural world.
+Caperna and Serafini define biophilic design as that kind of architecture, which is able to supply our inborn need of connection to life and to the vital processes. Biophilic space has been defined as the environment that strengthens life and supports the sociological and psychological components. These spaces can have positive health effects on people including reducing mental health issues in stressful spaces such as prisons, reducing chronic pain, improving memory, and lowering blood pressure. Examples of this being studied in medical settings include having a window looking out to see living plants is also shown to help speed up the healing process of patients in hospitals. Similarly, having plants in the same room as patients in hospitals also speeds up their healing process.
+Biophilic fractals are patterns designed to induce the health and well-being benefits associated with exposure to nature's scenery. These include stress-reduction and enhanced cognitive capacity. Designers and architects incorporate biophilic fractals into the built environment to counter the fact that people spend 92% of their time indoors and away from nature's scenery. ScienceDesignLab's Fractal Chapel in the state hospital in Graz, Austria is a prominent example and recipient of the 2025 IIDA (International Interior Design Association) Best of Competition Award.
+
+== Biophilia and conservation ==
+Because of our technological advancements and more time spent inside buildings and cars disconnects us from nature, biophilic activities and time spent in nature may be strengthening our connections as humans to nature, so people continue to have strong urges to reconnect with nature. The concern for a lack of connection with the rest of nature outside of us, is that a stronger disregard for other plants, animals and less appealing wild areas could lead to further ecosystem degradation and species loss. Therefore, reestablishing a connection with nature has become more important in the field of conservation. Examples would be more available green spaces in and around cities, more classes that revolve around nature and implementing smart design for greener cities that integrate ecosystems into them such as biophilic cities. These cities can also become part of wildlife corridors to help with migrational and territorial needs of other animals.
+
+== Biophilia in fiction ==
+Canadian author Hilary Scharper explicitly adapted E.O. Wilson's concept of biophilia for her ecogothic novel, Perdita. In the novel, Perdita (meaning "the lost one") is a mythological figure who brings biophilia to humanity.
+
+== See also ==
+Biocultural evolution
+Biomimetics
+Deep ecology
+Ecopsychology
+Environmental psychology
+Healthy building
+Nature deficit disorder
+Nature therapy
+Technobiophilia
+Ecosexuality
+
+== References ==
+
+== External links ==
+
+Edward O. Wilson's Biophilia Hypothesis
+Biophilia, biomimicry, and sustainable design
+The Economics of Biophilia - Terrapin Bright Green
+Biophilia, website for Biophilia magazine
+"Biophilic Design Patterns: Emerging Nature-Based Parameters for Health and Well-Being in the Built Environment" by Catherine O. Ryan, William D Browning, Joseph O Clancy, Scott L Andrews, Namita B Kallianpurkar (ArchNet-International Journal of Architectural Research)
+14 Patterns of Biophilic Design - Terrapin Bright Green
+"Biophilia: Does Visual Contact with Nature Impact on Health and Well-Being?" - National Center for Biotechnology Information
+"Biophilic Architecture and Biophilic Design" by Antonio Caperna, International Society of Biourbanism
+"Biourbanism for a healthy city: biophilia and sustainable urban theories and practices" Archived 2018-05-24 at the Wayback Machine by Antonio Caperna and Eleni Tracada, University of Derby (UK) - UDORA Repository
+"Introduction to Biophilic Biophilic Design" by Antonio Caperna, International Society of Biourbanism
+"Biophilic Design", Journal of Biourbanism Volume VI (1&2/2017) by Antonio Caperna Editor in Chief, International Society of Biourbanism
+
+Italian Academy of Biophilia (AIB) - Italian Academy of Biophilia (AIB)

data/en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis-0.md

@@ -0,0 +1,28 @@
+---
+title: "Black Sea deluge hypothesis"
+chunk: 1/3
+source: "https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:07.496507+00:00"
+instance: "kb-cron"
+---
+
+The Black Sea deluge is the best known of three hypothetical flood scenarios for the Late Quaternary history of the Black Sea that have been proposed since 1997. One other flood scenario proposes a rapid, even catastrophic, rise in sea level of the Black Sea. The maximum depth of the Bosporus and Dardanelles straits is 110 meters (360 ft) and 103 meters (338 ft), respectively, which would put them above the ocean levels in the Last Glacial Maximum, some 125 meters (410 ft) lower than in present times. The hypothesis is controversial, with other authors arguing for a more gradual inundation of the Black Sea.
+
+== History ==
+
+In 1997, William Ryan, Walter Pitman, Petko Dimitrov, and their colleagues first published the Black Sea deluge hypothesis. They proposed that a catastrophic inflow of Mediterranean seawater into the Black Sea freshwater lake occurred around 7,600 years ago, c. 5600 BCE.
+As proposed, the Early Holocene Black Sea flood scenario describes events that would have profoundly affected prehistoric settlement in Eastern Europe and adjacent parts of Asia and possibly was the basis of oral history concerning the myth of Noah's flood. Some archaeologists support this theory as an explanation for the lack of Neolithic sites in northern Turkey. In 2003, Ryan and coauthors revised the dating of the early Holocene flood to 8,800 years ago, c. 6800 BCE.
+Before that date, glacial meltwater had turned the Black and Caspian seas into vast freshwater lakes draining into the Aegean Sea. As glaciers retreated, some of the rivers emptying into the Black Sea declined in volume and changed course to drain into the North Sea. The levels of the lakes dropped through evaporation, while changes in worldwide hydrology caused global sea levels to rise.
+The rising Mediterranean finally spilled over a rocky sill at the Bosporus. The event flooded 100,000 km2 (39,000 sq mi) of land and significantly expanded the Black Sea shoreline to the north and west. According to these researchers, 50 km3 (10 cu mi) of water poured through each day. The Bosporus valley roared and surged at full spate for at least 300 days. They argued that the catastrophic inflow of seawater resulted from an abrupt sea-level jump that accompanied the Laurentide Ice Sheet collapse and the ensuing breach of a bedrock barrier in the Bosporus strait.
+
+=== Popular press accounts ===
+Popular discussion of this early Holocene Black Sea flood scenario was headlined in The New York Times in December 1996 and later published as a book.  In a series of expeditions widely covered by mainstream media, a team of marine archaeologists led by Robert Ballard identified what appeared to be ancient shorelines, freshwater snail shells, drowned river valleys, tool-worked timbers, and man-made structures in roughly 100 metres (330 ft) of water off the Black Sea coast of modern Turkey.
+
+== Late Pleistocene Great Flood hypothesis ==
+In 2003 and 2007, a more ancient catastrophic flood scenario was proposed by Andrei L. Chepalyga for the Late Quaternary sea level rise of the Black Sea. The hypothesis for a "Late Pleistocene Great Flood" argues that a brackish Neoeuxinian Lake, which occupied the Black Sea basin, was rapidly inundated by glacial meltwater overflow from the Caspian Sea via the Manych-Kerch Spillway shortly after the Late Glacial Maximum, about 17,000–14,000 years ago. These extensive meltwater flooding events linked several lacustrine and marine water bodies, starting with the southern edge of the Scandinavian Peninsula and southward, through spillways to the Manych-Kerch and Bosporus, ultimately forming what has been referred to as the Cascade of Eurasian Basins. This event is argued to have caused a rapid, if not catastrophic, rise in the level of the Black Sea. It might have imposed substantial stresses upon contemporary human populations and remained in cultural memory as the Great Flood. The authors also suggested that the event might have stimulated the beginning of shipping and horse domestication.
+
+== Black Sea gradual inundation hypothesis ==
+In addition to the early Holocene "Noah's Flood" scenario proposed by Ryan, Pitman, Dimitrov, and their colleagues and the Caspian Sea overflow scenario of Chepalyga, the non-catastrophic progressive flood model (or gradual inflow model) has been proposed to explain the Late Quaternary sea level history of the Black Sea.
+About 8,000 years ago, the level of the Marmara Sea would have risen high enough for two-way flow to start. The evidence used to support this scenario includes the disparate ages of sapropel deposition in the eastern Mediterranean Sea and Black Sea; buried back-stepping barrier islands observed on the Black Sea shelf; and an under-water delta in the Marmara Sea, near the Bosporus Strait, composed of Black Sea sediments.

data/en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis-1.md

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+---
+title: "Black Sea deluge hypothesis"
+chunk: 2/3
+source: "https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:07.496507+00:00"
+instance: "kb-cron"
+---
+
+== Counter-arguments ==
+ 
+Criticisms of the deluge hypothesis hinge on two main lines of arguments. The first mainly focuses on the water level of the Black Sea: if the magnitude and pace of the rise of the Black Sea level was moderate enough, or if it even outpaced the rise in the Aegean basin (with water flowing, when they reconnected, from the former to the latter as it does now), or if the straits were already opened (at a lower level than now) and the two basins already connected at the time of the hypothesised flood, the catastrophe hypothesis is voided. The second is the lack of archaeological evidence one would expect of a flood, such as impact on geology, wildlife or humans. 
+Since the end of the last glacial period, the global sea level has risen 120 m (390 ft). The flood hypothesis hinges on the geomorphology of the Bosporus since the end of the glacial age. The Black Sea area has been isolated and reconnected many times during the last 500,000 years.
+Opponents of the deluge hypothesis point to clues that water was flowing out of the Black Sea basin as late as 15,000 years ago.
+In this alternative scenario, much depends on the evolution of the Bosporus. According to a study from 2001, the modern sill is 32–34 m (105–112 ft) below sea level and consists of Quaternary sand over-lying Paleozoic bedrock in which three sills are found at 80–85 m (260–280 ft) below sea level. Sedimentation on these sills started before 10,000 years ago and continued until 5,300 years ago.
+A large part of the academic geological community also continues to reject the idea that there could have been enough sustained long-term pressure by water from the Aegean to dig through a supposed isthmus at the present Bosporus or enough of a difference in water levels, if any, between the two water basins.
+In 2007, a research anthology on the topic was published which made much of the earlier Russian research available in English for the first time and combined it with more recent scientific findings.
+The level in the Black Sea before the marine reconnection was estimated to have been 30 m (100 ft) below present sea level, rather than 80 m (260 ft) of the catastrophe theories or even lower; if the flood occurred at all, the sea level increase and the flooded area during the reconnection were significantly smaller than previously proposed. Since the depth of the Bosporus, in its middle furrow, at present varies from 36 to 124 m (118 to 407 ft), with an average depth of 65 m (213 ft), a calculated Stone Age shoreline in the Black Sea lying 30 m (100 ft) lower than in the present day would imply that the contact with the Mediterranean might never have been broken during the Holocene, and hence there could have been no sudden waterfall-style transgression. The flooding could have been "not so big".
+In 2011, several authors concluded that "there is no underwater archaeological evidence to support any catastrophic submergence of prehistoric Black Sea settlements during the late Pleistocene or early Holocene intervals".
+A 2012 study based on process length variation of the dinoflagellate cyst Lingulodinium machaerophorum shows no evidence for catastrophic flooding. 
+However, Geophysical, geochronological, and geochemical evidence points to a "fast transgression" of the submergence lasting between 10 and 200 years.
+A 2022 literature review concluded that there was insufficient evidence for a flood scenario. It was more likely that the waters of the Black Sea itself gradually outflowed to the Mediterranean. There was also no archaeological evidence of humans evacuating the area during the relevant time.
+
+== See also ==
+Black Sea undersea river – Saline water current in the Black Sea
+Altai flood – Prehistoric event in Central Asia
+Flood myth – Myth in which a great flood destroys civilization
+Noah's Ark – Vessel in the Genesis flood narrative
+4.2 kiloyear event – Severe climatic event starting around 2200 BCPages displaying short descriptions of redirect targets
+5.9 kiloyear event – North Atlantic ice rafting eventsPages displaying short descriptions of redirect targets
+8.2 kiloyear event – Rapid global cooling about 8,200 years agoPages displaying short descriptions of redirect targets
+West Siberian Glacial Lake – Periglacial lake of the Weichselian Glaciation
+Zanclean flood – Theoretical refilling of the Mediterranean Sea between the Miocene and Pliocene Epochs, flooding of the Mediterranean
+
+== References ==

data/en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis-2.md

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+---
+title: "Black Sea deluge hypothesis"
+chunk: 3/3
+source: "https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:07.496507+00:00"
+instance: "kb-cron"
+---
+
+== Further reading ==
+Aksu, Ali E.; Hiscott, Richard N.; Mudie, Peta J.; Rochon, André; Kaminski, Michael A.; Abrajano, Teofilo; Yaşar, Doğan (2002). "Persistent Holocene Outflow from the Black Sea to the Eastern Mediterranean Contradicts Noah's Flood Hypothesis". GSA Today. 12 (5): 4. Bibcode:2002GSAT...12e...4A. doi:10.1130/1052-5173(2002)012<0004:PHOFTB>2.0.CO;2.
+Yanko-Hombach, Valentina; Gilbert, Allan S.; Panin, Nicolae; Dolukhanov, Pavel M., eds. (2007). The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. doi:10.1007/978-1-4020-5302-3. ISBN 978-1-4020-4774-9.
+Dimitrov, Petko; Dimitrov, Dimitar (2004). The Black Sea, the Flood and the ancient myths. "Slavena", Varna. doi:10.13140/RG.2.2.18954.16327.
+Dimitrov, Dimitar Petkov (2010). Geology and Non-traditional resources of the Black Sea. LAP (Lambert Academic Publishing AG), Saarbrucken, Germany. doi:10.13140/RG.2.2.20631.88486.
+Eris, K.; Ryan, W. B. F.; Cagatay, N.; Sancar, Ü.; Lericolais, G.; Menot, G.; Bard, E. (2008). "The timing and evolution of the post-glacial transgression across the Sea of Marmara shelf south of İstanbul" (PDF). Marine Geology. 243 (1–4): 57–76. doi:10.1016/j.margeo.2007.04.010.
+Gökaşan, E.; Algan, O.; Tur, H.; Meriç, E.; Türker, A.; Şimşek, M. (2005). "Delta formation at the southern entrance of Istanbul Strait (Marmara sea, Turkey): a new interpretation based on high-resolution seismic stratigraphy". Geo-Marine Letters. 25 (6): 370–377. Bibcode:2005GML....25..370G. doi:10.1007/s00367-005-0215-4. S2CID 130792746.
+Keith, M.L.; Anderson, G.M. (1963). "Radiocarbon Dating: Fictitious Results with Mollusk Shells". Science. 141 (3581): 634–637. Bibcode:1963Sci...141..634K. doi:10.1126/science.141.3581.634. PMID 17781758. S2CID 24213036.
+Lericolais, G.; et al. (2009). "High frequency sea level fluctuations recorded in the Black Sea since the LGM". Global and Planetary Change. 66 (1–2): 65–75. Bibcode:2009GPC....66...65L. doi:10.1016/j.gloplacha.2008.03.010. S2CID 140710053.
+Lippsett, Lonny (14 August 14, 2009). "Noah's Not-so-big Flood" Oceanus.
+National Geographic News. 2009-02-06. "Noah's Flood" Not Rooted in Reality, After All?
+"Ballard and the Black Sea". National Geographic Society.
+Schiermeier, Quirin (August 2004). "Noah's flood". Nature. 430 (7001): 718–719. doi:10.1038/430718a. PMID 15306780. Gale A186293984.
+The late glacial Great Flood in the Ponto-Caspian basin (Archived 2015-05-12 at the Wayback Machine). paleogeo.org.
+Ryan, William B.F.; Pitman, Walter C.; Major, Candace O.; Shimkus, Kazimieras; Moskalenko, Vladamir; Jones, Glenn A.; Dimitrov, Petko; Gorür, Naci; Sakinç, Mehmet; Yüce, Hüseyin (April 1997). "An abrupt drowning of the Black Sea shelf". Marine Geology. 138 (1–2): 119–126. Bibcode:1997MGeol.138..119R. doi:10.1016/s0025-3227(97)00007-8.
+Ryan, William B.; Pitman, Walter C. (2000). Noah's Flood: The new scientific discoveries about the event that changed history. Simon & Schuster. ISBN 978-0-684-85920-0.
+Shopov Y. Y., Т. Yalamov, P. Dimitrov, D. Dimitrov and B. Shkodrov (2009b) Initiation of the Migration of Vedic Aryans to India by a Catastrophic Flooding of the Black Sea by Mediterranean Sea during the Holocene". Extended Abstracts of LIMPACS-3 International Conference of IGBP, PAGES, 5–8 March 2009, Chandigarh, India, pp. 126–127.* Sperling, M.; Schmiedl, G.; Hemleben, C.; Emeis, K. C.; Erlenkeuser, H.; Grootes, P. M. (2003). "Black Sea impact on the formation of eastern Mediterranean sapropel S1? Evidence from the Marmara Sea". Palaeogeography, Palaeoclimatology, Palaeoecology. 190: 9–21. Bibcode:2003PPP...190....9S. doi:10.1016/s0031-0182(02)00596-5.
+Yanko-Hombach, Valentina; Allan S. Gilbert; Nicolae Panin; Pavel M. Dolukhanov, eds. (2007). The Black Sea Flood Question. Dordrecht, Netherlands: Springer. ISBN 978-1-4020-4774-9. OCLC 77482394.

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+---
+title: "Broad spectrum revolution"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Broad_spectrum_revolution"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:09.941400+00:00"
+instance: "kb-cron"
+---
+
+The broad spectrum revolution (BSR) hypothesis, proposed by Kent Flannery in a 1968 paper presented to a London University symposium, suggested that the emergence of the Neolithic in southwest Asia was prefaced by increases in dietary breadth among foraging societies. The broad spectrum revolution followed the last glacial period around 15,000 BP in the Middle East and 12,000 BP in Europe. During this time, there was a transition from focusing on a few main food sources to gathering/hunting a "broad spectrum" of plants and animals.
+
+
+== Hypothesis details ==
+Flannery's hypothesis was meant to help explain the adoption of agriculture in the Neolithic Revolution. Unpersuaded by "the facile explanation of prehistoric environmental change" Flannery suggested (following Lewis Binford's equilibrium model) that population growth in optimal habitats led to demographic pressure within nearby marginal habitats as daughter groups migrated.  The search for more food within these marginal habitats forced foragers to diversify the types of food sources harvested, broadening the subsistence base outward to include more fish, small game, waterfowl, invertebrates (such as snails and shellfish), as well as previously ignored or marginal plant sources.  Most importantly, Flannery argues that the need for more food in these marginal environments led to the deliberate cultivation of certain plant species, especially cereals.  In optimal habitats, these plants naturally grew in relatively dense stands, but required human intervention in order to be efficiently harvested in marginal zones.  Thus, the broad spectrum revolution set the stage for domestication and rise of permanent agricultural settlement.
+
+
+=== Characteristics ===
+A BSR is likely to manifest as both an increased spectrum of food resources and an evenness in the exploitation of high- and low-value prey. Under a broad spectrum economy a greater amount of low-value prey (i.e. high cost-to-benefit ratio) would be included because there are insufficient high-value prey to reliably satisfy a population's needs. In terms of plants, it would be expected that foodstuffs that had once been ignored because of difficulty of extraction were now included in a diet. In terms of fauna, animal prey which was previously considered an inefficient use of resources (particularly small, fast mammals or fish) could now also be worthwhile. In other words, increasing scarcity made the extra effort necessary for survival.
+In the Middle East, the broad spectrum revolution led to an increase in the production of food.  The growth and reproduction of certain plants and animals became vastly popular.  Because large animals became quite scarce, people had to find new resources of food and tools elsewhere.  Interests focused on smaller game like fish, rabbits, and shellfish because the reproduction rate of small animals is much greater than that of large animals.
+
+
+=== Stimulation ===
+The most commonly accepted stimulation for the BSR is demographic pressures on the landscape, under which over-exploitation of resources meant narrow diets restricted to high-value prey could no longer feed the expanding population.
+The broad-spectrum revolution has also been linked to climatic changes, including sea level rises during which:
+
+Conditions became more inviting to marine life offshore in shallow, warm waters.
+Quantity and variety of marine life increased drastically as did the number of edible species.
+Because the rivers' power weakened with rising waters, the currents flowing into the ocean were slow enough to allow salmon and other fish to ascend upstream to spawn.
+Birds found refuge next to riverbeds in marsh grasses and then proceeded to migrate across Europe in the wintertime.
+
+
+== Example ==
+The Japanese site Nittano (inlet near Tokyo) was occupied several times between 6000 and 5000 BP. The Jōmon culture occupied Nittano at over 30,000 sites known in Japan. People hunted deer, pigs, bears, antelope, fish, shellfish, and gathered plants. Sites have yielded over 300 sample remains of shellfish and 180 sample remains of plants.
+
+
+== Criticism ==
+The broad spectrum revolution has been a subject of intense debate since it was first proposed, but its basic arguments are well-supported.
+
+
+== References ==
+Notes
+
+Bibliography
+
+Kent Flannery, "Origins and Ecological Effects of Early Domestication in Iran and the Near East," The Domestication and Exploitation of Plants and Animals, eds. Peter J. Ucko and G.W. Dimbleby (Chicago: Aldine Publishing Co., 1969), 73–100
+Mary Stiner, "Thirty Years on the 'Broad Spectrum Revolution' and Paleolithic Demography," PNAS, 98, no. 13 (2001): 6993–6996;
+Ehud Weiss et al., "The Broad Spectrum Revisited: Evidence from Plant Remains," PNAS, 101, no. 26 (2004): 9551–9555

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+---
+title: "Carbohydrate–insulin model"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Carbohydrate–insulin_model"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:11.063944+00:00"
+instance: "kb-cron"
+---
+
+The carbohydrate-insulin model (CIM) posits that obesity is caused by excess consumption of carbohydrate, which then disrupts normal insulin metabolism leading to weight gain and weight-related illnesses. It is contrasted with the mainstream energy balance model (EBM), which holds that obesity is caused by an excess in calorie consumption compared to calorie expenditure. According to the carbohydrate–insulin model, low-carbohydrate diets would be the most effective in causing long-term weight loss. Notable proponents of the carbohydrate–insulin model include Gary Taubes and David Ludwig. The CIM has been tested in mice and humans. Although some experts consider that these studies falsified the CIM, proponents disagree. Available evidence does not support the existence of a long-term advantage in weight loss for low-carbohydrate diets.
+
+
+== See also ==
+Adipose tissue
+Appetite
+Basal metabolic rate
+Energy homeostasis
+Glucagon
+Glycemic index
+Glycemic load
+Hyperinsulinemia
+Insulin sensitivity
+Insulin
+Ketogenic diet
+Leptin
+Lipogenesis
+Low-carbohydrate diet
+Low-glycemic index diet
+Metabolic Syndrome
+Obesity
+Refined carbohydrates
+Set point theory
+Sugar
+Ultra-processed food
+
+
+== References ==

data/en.wikipedia.org/wiki/Coastal_migration_(Americas)-0.md

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+---
+title: "Coastal migration (Americas)"
+chunk: 1/3
+source: "https://en.wikipedia.org/wiki/Coastal_migration_(Americas)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:13.444822+00:00"
+instance: "kb-cron"
+---
+
+The coastal migration hypothesis is one of two leading hypotheses about the settlement of the Americas at the time of the Last Glacial Maximum. It proposes one or more migration routes involving watercraft, via the Kurile island chain, along the coast of Beringia and the 
+archipelagos off the Alaskan-British Columbian coast, continuing down the coast to Central and South America.
+
+The alternative is the hypothesis solely by interior routes, which assumes migration along an  ice-free corridor between the Laurentide and Cordilleran ice sheets during the Last Glacial Maximum.The coastal migration hypothesis has been bolstered by findings such as the report that the sediments in the Port Eliza caves on Vancouver Island indicate the possibility of a survivable climate as far back 16 ka (16,000 years) in the area, while the continental ice sheets were nearing their maximum extent. Despite such research, the hypothesis is still subject to considerable debate.
+Carlson, Erlandson, and others have argued for a coastal migration from Alaska to the Pacific Northwest pre-11ka (before ≈13,000 calendar years ago) that predates the hypothesized migration of Clovis people moving south through an ice-free corridor located near the continental divide. The coastal migrants may have been followed by the Clovis culture when the final retreat of the Cordilleran Ice Sheet opened migration routes between interior and coastal Alaska.
+A 2017 discovery on Triquet Island by an archaeological team from the University of Victoria appears to verify local First Nation oral history traditions that the island was inhabited during the ice age. A hearth excavated at the site was determined by radiocarbon dating to be between 13,613 and 14,086 years old, making it one of the oldest settlements in North America.
+While some archaeologists believe that the Clovis people moved south from Alaska through an ice-free corridor located between modern British Columbia and Alberta, recent dating of Clovis and similar Paleoindian sites in Alaska suggest that Clovis technology actually moved from the south into Alaska following the melting of the continental ice sheets at about 10.5 ka.
+In North America, the earliest dog remains were found in Lawyer's Cave on the Alaskan mainland east of Wrangell Island in the Alexander Archipelago of southeast Alaska; radiocarbon dating indicates it is 10,150 years old. A genetic-based estimate indicates that this dog's lineage had split from the Siberian Zhokhov Island dog lineage 16,700 years ago. This timing coincides with the suggested opening of the North Pacific coastal route into North America.
+
+== Sea levels ==
+Dating the initial coastal migration is challenging because of the flooding of early settlement sites by the rise of the eustatic sea level accompanying deglaciation.  Dates for sites such as ones at Ground Hog Bay in SE Alaska (10.2 ka) and Namu, about 800 km south of Ground Hog Bay near modern Bella Coola (9.7 ka) thus represent early mainland settlement above the present-day sea level after earlier waterborne migration while the sea level was lower and the coastal mainland was still glaciated. Full understanding of the initial migration requires careful reconstruction of the land and ecological resources available to the migrants in their contemporary environment.
+Evidence from Southeast Alaska and Haida Gwaii (Queen Charlotte Islands) in British Columbia, provides some data about food and land resources during early settlement.  Fedje and Christensen (1999:642) have identified several sites on Haida Gwaii that date to post 9ka. The oldest human yet found on the west coast of North America are from On Your Knees Cave, which is on Prince of Wales Island in Southeast Alaska.  The individual, a young man in his early twenties when he died, has been dated to ≈10,000 cal BP and isotopic analyses indicate he was raised on a diet primarily of marine foods.
+These data suggest human occupation when the sea level was lower than present, and that submerged archaeological sites could occur along the paleocoastline beyond the current shorelines of Haida Gwaii (Fedje & Christensen, 1999) and Southeast Alaska.
+Between 13 and 10.5 ka, Haida Gwaii had more than double its current land area (Fedje & Christensen, 1999:638).  This area was flooded with a rapid rise in sea level between 11 and 9 ka. (Fedje & Christensen, 1999:638).  Therefore, evidence of initial human occupation on the paleocoastline of Haida Gwaii would now be below sea level. Conversely, older sites that are located near modern shorelines would have been approximately 24 km (15 mi) from the coast (Fedje & Christensen, 1999:638).
+The antiquity of the lithic scatters that Fedje and Christensen (1999) have found in intertidal zones along the Haida Gwaii coast suggests an early human occupation of the area.
+Fedje and Christensen (1999) support Carlson (1990), and Fladmark's (1975, 1979 & 1989) initial coastal migration model rather than the ice-free corridor model through their investigations of intertidal zones on Haida Gwaii.
+
+== The peopling of the Americas ==
+The timing and route of human arrival to mid-latitude North America is highly contested and both the terrestrial and coastal routes suffer from a paucity of archaeological evidence. Beringia is very difficult to access in modern-day because it is now below current sea level. However, hypotheses have been made based on mitochondrial DNA research to address the question of whether or not humans left Beringia and settled mid-latitude America during the LGM or stayed in Beringia throughout the LGM.

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+---
+title: "Coastal migration (Americas)"
+chunk: 2/3
+source: "https://en.wikipedia.org/wiki/Coastal_migration_(Americas)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:13.444822+00:00"
+instance: "kb-cron"
+---
+
+=== Three-wave model ===
+The Three-wave model is an older model that attempts to explain the peopling of the Americas suggested by Greenberg et al. (1986). Using linguistic and genetic data as well as dental anthropology, Greenberg et al. subdivided Native Americans into three groups: Amerind, Na-Dene, and Aleut-Inuit. They explained the linguistic, anatomical, and genetic differences they found in each group as a result of separate migrations or waves out of Northeast Asia to the Americas.
+This model has been criticized by anthropologist Emőke J.E. Szathmáry who thought that Greenberg's study overstated biological difference. Szathmáry argued that the differences between each group could be better explained by isolation rather than the three migrations. In 1977, Bonatto and Szathámry (1997) concluded that the presence of glaciers isolated the populations from one another, causing them to settle in Beringia rather than use it as a bridge or corridor for migration to mid-latitude America. Bonatto and Szathmáry suggest that after the LGM, humans actually migrated out of Beringia rather than out of Asia.
+
+=== Beringian "Standstill" hypothesis ===
+The Beringian "Standstill" Hypothesis proposed by Tamm et al. (2007) builds on Bonatto and Szathmáry's idea of migration out of Beringia after the LGM. Using mitochondrial DNA (mDNA) and computer modeling of ice sheets, Tamm et al. estimate an isolation period in Beringia of about ≈10,000 years, concluding that the isolated Beringian populations spread throughout mid-latitude and South America after the LGM due to blocked access to North America before 15,000 cal BP.
+At the turn of the 21st century, more research began to favor the coastal migration theory over terrestrial theories for the peopling of the Americas. Paleoecological evidence suggests that travel along the coast would have been possible between 13 and 11 ka as the ice sheets were retreating. The coastal region was quite hospitable by 13 ka to peoples with watercraft and a maritime adaptation.
+
+=== Kelp highway hypothesis ===
+This hypothesis addresses how humans could have settled the Americas before the ice sheets retreated, allowing for terrestrial migration. Erlandson et al. (2007) suggest that coastal migrations and settlements happened in higher latitudes, such as 35-70°N, where coastal ecosystems would be more productive because of geography and upwelling in the Northern Pacific Rim. The different kelps of the Pacific Rim are major contributors to the areas of productivity and biodiversity and support a wide variety of life such as marine mammals, shellfish, fish, seabirds, and edible seaweeds that would also support a coastal community of hunter-gatherers.
+While the benefits of kelp forests are very clear in the present day Pacific Rim, Erlandson et al. address the difficulties of understanding the ancient kelp forests as they would have existed at the end of the LGM. But, they were able to estimate where the kelp forests might have been distributed.
+
+==== Archeological and geological evidence ====
+Archaeological sites from the Pacific Northwest to Baja California have offered more evidence to suggest the coastal migration theory. Sites in the North Pacific have been discovered and researched to help develop a baseline of early coastal colonization data.  In California, archeological sites with dates that support human settlement in the migration period 12,000 -7,000 ybp are: Borax Lake, the Cross Creek Site, Santa Barbara Channel Islands, Santa Barbara Coast's Sudden Flats, and the Scotts Valley site, CA-SCR-177. The Arlington Springs Man is an excavation of 10,000-year-old human remains in the Channel Islands. Marine shellfish remains associated with kelp forests were recovered in the Channel Island sites and at other sites such as Daisy Cave and Cardwell Bluffs dated between 12,000 and 9000 cal BP.
+In South America, evidence of human presence as early as 12,500 cal BP was discovered at the Monte Verde site pointing to coastal migration south over inland migration as the ice sheet would not yet be retreated.
+Further evidence to support the coastal migration hypothesis has been found in the biological viability of regions after deglaciation. Lesnek et al. 2018 found that the deglaciation of the Pacific coastal corridor allowed for biological productivity, availability of food resources, and an accessible migration route for early colonization.
+
+==== Zoo-archaeological evidence ====
+Further evidence of a coastal ecology sufficient to support early coastal migrants comes from zoo-archaeological finds along the Northwest coast.  Goat remains as old as 12 ka have been found on Vancouver Island, British Columbia, as well as bear remains dating to 12.5 ka in the Prince of Wales Archipelago, British Columbia. Even older remains of black and brown bear, caribou, sea birds, fish, and ringed seal have been dated from a number of caves in Southeast Alaska by paleontologist Timothy Heaton.  This means that there were enough land and floral resources to support large land mammals and, theoretically, humans.

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+---
+title: "Coastal migration (Americas)"
+chunk: 3/3
+source: "https://en.wikipedia.org/wiki/Coastal_migration_(Americas)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:13.444822+00:00"
+instance: "kb-cron"
+---
+
+=== Watercraft ===
+Fedje and Christensen (1999:648) also argue that the coast was likely colonized before 13 ka, largely based on watercraft evidence from Japan before 13 ka. Dietary evidence from middens in Indonesia indicates the development of offshore fishing, requiring watercraft, between 35 and 40 ka.  Sea-going cultures were mobile in the island-rich environment off the late Pleistocene coast of east Asia, facilitating the spread of marine technology and skills through the Philippines, up the Ryukyu chain, to Japan.  Warming of the climate after about 16 ka (although glaciation would remain) could have provided an impetus for seaborne migration up the Kurile island chain towards North America, through some combination of a more hospitable climate and increased ocean productivity. Although no boats have been recovered from early Pacific Coast archaeological sites, this may be due to poor preservation of organic materials and the inundation of coastal areas mentioned above.  We can still infer water travel based on the presence of artifacts made by humans found at island sites.
+Anecdotal evidence comes from the surviving Bella Bella oral tradition, as recorded by Franz Boas in 1898.  "In the beginning there was nothing but water and ice and a narrow strip of shoreline." Some believe this story describes the environment of the Northwest Coast during the last deglaciation.
+
+=== Migration south ===
+Further south, California's Channel Islands have also produced evidence for early seafaring by Paleoindian (or Paleocoastal) peoples. Santa Rosa and San Miguel islands, for instance, have produced 11 sites dating to the Terminal Pleistocene, including the Arlington Man site dated to ≈11 ka and Daisy Cave occupied about 10.7 ka.
+Significantly, the Channel Islands were not connected to the mainland coast during the Quaternary, so maritime peoples contemporary with the Clovis and Folsom complexes in the interior had to have seaworthy boats to colonize them. The Channel Islands have also produced the earliest fishhooks yet found in the Americas, bone bipoints (gorges) that date between about 8.5 and 9 ka (10,000 and 9500 calendar years).
+Even further south, the Monte Verde site in Chile has become accepted as the earliest settlement in South America, dating to at least 14,500 years ago. This is believed to indicate migration through northern coastal regions before that date. The Monte Verde site produced the remains of nine types of seaweeds, including kelp.
+
+== Western Stemmed Tradition ==
+Paleocoastal Channel Islands settlers were equipped with finely made stemmed points, as well as chipped stone crescents generally similar to those found in Western Stemmed Tradition (WST) sites of western North America.
+Such ancient stemmed point lithic technology is widely attested at many sites in North America. For example, at Buttermilk Creek, Texas (Debra L. Friedkin site) these artifacts are dated to ≈13.5 to ≈15.5 ka ago. At the nearby Gault site, stemmed projectile points dated to ≈16 ka ago are also found; they are located below a Clovis stratigraphic horizon at this site.
+At Paisley Caves, Oregon, these WST projectile points are dated to ≈12.7 to ≈13 ka ago—soon after the earliest occupation level here. At Cooper's Ferry, Idaho, similar WST dates are reported.
+At Meadowcroft Rockshelter, Pennsylvania, the Miller point (similar to WST) can be dated to ≈14 ka ago.
+In Mexico, a stemmed projectile point is associated with the bones of a mammoth buried at Santa Isabel Iztapan (Ixtapan). Four hundred meters away, two other stemmed points were associated with butchered mammoth bones. The dates are similar to the above.
+In South America, there is also a long history of the use of stemmed points. Here they are known as 'El Jobo points', from which later developed 'Stemmed Fishtail points'. In particular, El Jobo points are found at Monte Verde, Chile in use as early as ≈14.2 ka ago. El Jobo and Fishtail points became widespread across South America ≈13 ka ago.
+On the Channel Islands, Jon Erlandson and his colleagues have identified several early shell middens located near sources of chert, which was used to make stone tools. These quarry/workshop sites have been dated between about 10 and 10.5 ka and contain crescents and finely made stemmed projectile points probably used to hunt birds and sea mammals, respectively.
+
+== See also ==
+Settlement of the Americas § Pacific coastal route
+Huaca Prieta
+Solutrean hypothesis
+
+== References ==
+
+== Literature ==
+Dillehay, Tom D.; Steve Goodbred; Mario Pino; Víctor F. Vásquez Sánchez; Teresa Rosales Tham; James Adovasio; Michael B. Collins; Patricia J. Netherly; Christine A. Hastorf; Katherine L. Chiou; Dolores Piperno; Isabel Rey; Nancy Velchoff (24 May 2017). "Simple technologies and diverse food strategies of the Late Pleistocene and Early Holocene at Huaca Prieta, Coastal Peru". Science Advances. 3 (5) e1602778. American Academy for the Advancement of Science. Bibcode:2017SciA....3E2778D. doi:10.1126/sciadv.1602778. PMC 5443642. PMID 28560337.
+Fedje, Daryl W.; Christensen, Tina (Oct 1999). "Modeling Paleoshorelines and Locating Early Holocene Coastal Sites in Haida Gwaii". American Antiquity. 64 (4): 635–652. doi:10.2307/2694209. JSTOR 2694209.
+Hardy, Karen; Erlandson, Jon M.; Braje, Todd J.; Ainis, Amira F.; Culleton, Brendan J.; Gill, Kristina M.; Hofman, Courtney A.; Kennett, Douglas J.; Reeder-Myers, Leslie A.; Rick, Torben C. (2020). "Maritime Paleoindian technology, subsistence, and ecology at an ≈11,700 year old Paleocoastal site on California's Northern Channel Islands, USA". PLOS ONE. 15 (9) e0238866. Bibcode:2020PLoSO..1538866E. doi:10.1371/journal.pone.0238866. ISSN 1932-6203. PMC 7498104. PMID 32941444.
+Waters, Michael R.; Keene, Joshua L.; Forman, Steven L.; Prewitt, Elton R.; Carlson, David L.; Wiederhold, James E. (2018). "Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas". Science Advances. 4 (10) eaat4505. Bibcode:2018SciA....4.4505W. doi:10.1126/sciadv.aat4505. ISSN 2375-2548. PMC 6200361. PMID 30397643.

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+---
+title: "Cognitive inertia"
+chunk: 1/4
+source: "https://en.wikipedia.org/wiki/Cognitive_inertia"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:22.921691+00:00"
+instance: "kb-cron"
+---
+
+Cognitive inertia is the tendency – for a particular orientation in an individual's thinking about a matter, belief, or strategy – to resist change. Clinical and neuroscientific literature often describes it as a lack of motivation to generate cognitive processes needed to attend to a matter or problem. 
+The physics term "inertia" emphasizes resistance to change in a mode of cognitive processing that has been used for a substantial time. Commonly confused with belief perseverance, cognitive inertia is  perseverance in an interpretation of information, not perseverance in the belief itself.
+Cognitive inertia has been causally implicated in disregard of impending threats to one's health or environment, in enduring political values, and in deficits in task switching. Interest in the phenomenon was taken up by economic and industrial psychologists primarily to explain resistance to change in brand loyalty, in group brainstorming, and in business strategizing. 
+In a clinical setting, cognitive inertia has been used as a diagnostic tool for neurodegenerative diseases, depression, and anxiety. 
+Critics have commented that the term "cognitive inertia" oversimplifies resistant thought processes and suggest a more integrative approach involving motivation, emotion, and developmental factors.
+
+== History and methods ==
+
+=== Early history ===
+The idea of cognitive inertia has its roots in philosophical epistemology. Early allusions to a reduction of cognitive inertia can be found in the Socratic dialogues written by Plato. Socrates builds his argument by using the detractor's beliefs as the premise of his argument's conclusions. In doing so, Socrates reveals the detractor's fallacy of thought, inducing the detractor to change their mind or face the reality that their thought processes are contradictory. Ways to combat persistence of cognitive style are also seen in Aristotle's syllogistic method which employs logical consistency of the premises to convince an individual of the conclusion's validity.
+At the beginning of the twentieth century, two of the earliest experimental psychologists, Müller and Pilzecker, defined perseveration of thought to be "the tendency of ideas, after once having entered consciousness, to rise freely again in consciousness". Müller described perseveration by illustrating his own inability to inhibit old cognitive strategies with a syllable-switching task, while his wife easily switched from one strategy to the next. One of the earliest personality researchers, W. Lankes, more broadly defined perseveration as "being confined to the cognitive side" and possibly "counteracted by strong will". These early ideas of perseveration were the precursor to how the term cognitive inertia would be used to study certain symptoms in patients with neurodegenerative disorders, rumination and depression.   
+
+=== Cognitive psychology ===
+Originally proposed by William J. McGuire in 1960, the theory of cognitive inertia was built upon emergent theories in social psychology and cognitive psychology that centered around cognitive consistency, including Fritz Heider's balance theory and Leon Festinger's cognitive dissonance. McGuire used the term cognitive inertia to account for an initial resistance to change how an idea was processed after new information, that conflicted with the idea, had been acquired.
+In McGuire's initial study involving cognitive inertia, participants gave their opinions of how probable they believed various topics to be. A week later, they returned to read messages related to the topics they had given their opinions on. The messages were presented as factual and were targeted to change the participants' belief in how probable the topics were. Immediately after reading the messages, and one week later, the participants were again assessed on how probable they believed the topics to be. Discomforted by the inconsistency of the related information from the messages and their initial ratings on the topics, McGuire believed the participants would be motivated to shift their probability ratings to be more consistent with the factual messages. However, the participants' opinions did not immediately shift toward the information presented in the messages. Instead, a shift towards consistency of thought on the information from the messages and topics grew stronger as time passed, often referred to as "seepage" of information. The lack of change was reasoned to be due to persistence in the individual's existing thought processes which inhibited their ability to re-evaluate their initial opinion properly, or as McGuire called it, cognitive inertia.
+
+==== Probabilistic model ====
+Although cognitive inertia was related to many of the consistency theories at the time of its conception, McGuire used a unique method of probability theory and logic to support his hypotheses on change and persistence in cognition. Utilizing a syllogistic framework, McGuire proposed that if three issues (a, b and c) were so interrelated that an individual's opinion were in complete support of issues a and b then it would follow their opinion on issue c would be supported as a logical conclusion. Furthermore, McGuire proposed if an individual's belief in the probability (p) of the supporting issues (a or b) was changed, then not only would the issue (c) explicitly stated change, but a related implicit issue (d) could be changed as well. More formally:
+
+the required change (
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+) on c necessary for maintaining logical consistency among the opinions is
+
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(c) = 
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(a & b)
+which, assuming that a and b are independent events i.e., that p(a & b) = p(a) p(b) becomes
+
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(c) = 
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(a) p(b) + 
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(b) p(a) + 
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(a) 
+  
+    
+      
+        Δ
+      
+    
+    {\displaystyle \Delta }
+  
+p(b)

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+---
+title: "Cognitive inertia"
+chunk: 2/4
+source: "https://en.wikipedia.org/wiki/Cognitive_inertia"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:22.921691+00:00"
+instance: "kb-cron"
+---
+
+where p(a) and p(b) refer to the initial opinions, before the communication induced changes.
+This formula was used by McGuire to show that the effect of a persuasive message on a related, but unmentioned, topic (d) took time to sink in. The assumption was that topic d was predicated on issues a and b, similar to issue c, so if the individual agreed with issue c then so too should they agree with issue d. However, in McGuire's initial study immediate measurement on issue d, after agreement on issues a, b and c, had only shifted half the amount that would be expected to be logically consistent. Follow-up a week later showed that shift in opinion on issue d had shifted enough to be logically consistent with issues a, b, and c, which not only supported the theory of cognitive consistency, but also the initial hurdle of cognitive inertia.
+The model was based on probability to account for the idea that individuals do not necessarily assume every issue is 100% likely to happen, but instead there is a likelihood of an issue occurring and the individual's opinion on that likelihood will rest on the likelihood of other interrelated issues.   
+
+== Examples ==
+
+=== Public health ===
+
+==== Historical ====
+Group (cognitive) inertia, how a subset of individuals view and process an issue, can have detrimental effects on how emergent and existing issues are handled. In an effort to describe the almost lackadaisical attitude from a large majority of U.S. citizens toward the insurgence of the Spanish flu in 1918, historian Tom Dicke has proposed that cognitive inertia explains why many individuals did not take the flu seriously. At the time, most U.S. citizens were familiar with the seasonal flu. They viewed it as an irritation that was often easy to treat, infected few, and passed quickly with few complications and hardly ever a death. However, this way of thinking about the flu was detrimental to the need for preparation, prevention, and treatment of the Spanish flu due to its quick spread and virulent form until it was much too late, and it became one of the most deadly pandemics in history.
+
+==== Contemporary ====
+In the more modern period, there is an emerging position that anthropogenic climate change denial is a kind of cognitive inertia. Despite the evidence provided by scientific discovery, there are still those – including nations – who deny its incidence in favor of existing patterns of development.
+
+=== Geography ===
+To better understand how individuals store and integrate new knowledge with existing knowledge, Friedman and Brown tested participants on where they believed countries and cities to be located latitudinally and then, after giving them the correct information, tested them again on different cities and countries. The majority of participants were able to use the correct information to update their cognitive understanding of geographical locations and place the new locations closer to their correct latitudinal location, which supported the idea that new knowledge affects not only the direct information but also related information. However, there was a small effect of cognitive inertia as some areas were unaffected by the correct information, which the researchers suggested was due to a lack of knowledge linkage in the correct information and new locations presented.
+
+=== Group membership ===
+
+==== Politics ====
+The persistence of political group membership and ideology is suggested to be due to the inertia of how the individual has perceived the grouping of ideas over time. The individual may accept that something counter to their perspective is true, but it may not be enough to tip the balance of how they process the entirety of the subject.
+Governmental organizations can often be resistant or glacially slow to change along with social and technological transformation. Even when evidence of malfunction is clear, institutional inertia can persist. Political scientist Francis Fukuyama has asserted that humans imbue intrinsic value on the rules they enact and follow, especially in the larger societal institutions that create order and stability. Despite rapid social change and increasing institutional problems, the value placed on an institution and its rules can mask how well an institution is functioning as well as how that institution could be improved. The inability to change an institutional mindset is supported by the theory of punctuated equilibrium, long periods of deleterious governmental policies punctuated by moments of civil unrest. After decades of economic decline, the United Kingdom's referendum to leave the EU was seen as an example of the dramatic movement after a long period of governmental inertia.
+
+==== Interpersonal roles ====
+The unwavering views of the roles people play in our lives have been suggested as a form of cognitive inertia. When asked how they would feel about a classmate marrying their mother or father, many students said they could not view their classmate as a step-father/mother. Some students went so far as to say that the hypothetical relationship felt like incest.
+Role inertia has also been implicated in marriage and the likelihood of divorce. Research on couples who cohabit together before marriage shows they are more likely to get divorced than those who do not. The effect is most seen in a subset of couples who cohabit without first being transparent about future expectations of marriage. Over time, cognitive role inertia takes over, and the couple marries without fully processing the decision, often with one or both of the partners not fully committed to the idea. The lack of deliberative processing of existing problems and levels of commitment in the relationship can lead to increased stress, arguments, dissatisfaction, and divorce.  
+
+== In business ==
+Cognitive inertia is regularly referenced in business and management to refer to consumers' continued use of products, a lack of novel ideas in group brainstorming sessions, and lack of change in competitive strategies.

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+title: "Cognitive inertia"
+chunk: 3/4
+source: "https://en.wikipedia.org/wiki/Cognitive_inertia"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:22.921691+00:00"
+instance: "kb-cron"
+---
+
+=== Brand loyalty ===
+Gaining and retaining new customers is essential to whether a business succeeds early on. To assess a service, product, or likelihood of customer retention, many companies will invite their customers to complete satisfaction surveys immediately after purchasing a product or service. However, unless the satisfaction survey is completed immediately after the point of purchase, the customer response is often based on an existing mindset about the company, not the actual quality of experience. Unless the product or service is extremely negative or positive, cognitive inertia related to how the customer feels about the company will not be inhibited, even when the product or service is substandard. These satisfaction surveys can lack the information businesses need to improve a service or product that will allow them to survive against the competition.
+
+=== Brainstorming ===
+Cognitive inertia plays a role in why a lack of ideas is generated during group brainstorming sessions. Individuals in a group will often follow an idea trajectory, in which they continue to narrow in on ideas based on the very first idea proposed in the brainstorming session. This idea trajectory inhibits the creation of new ideas central to the group's initial formation.
+In an effort to combat cognitive inertia in group brainstorming, researchers had business students either use a single-dialogue or multiple-dialogue approach to brainstorming. In the single dialogue version, the business students all listed their ideas. They created a dialogue around the list, whereas, in the multi-dialogue version, ideas were placed in subgroups that individuals could choose to enter and talk about and then freely move to another subgroup. The multi-dialogue approach was able to combat cognitive inertia by allowing different ideas to be generated in sub-groups simultaneously and each time an individual switched to a different sub-group, they had to change how they were processing the ideas, which led to more novel and high-quality ideas.
+
+=== Competitive strategies ===
+Adapting cognitive strategies to changing business climates is often integral to whether or not a business succeeds or fails during economic stress. In the late 1980s in the UK, real estate agents' cognitive competitive strategies did not shift with signs of an increasingly depressed real estate market, despite their ability to acknowledge the signs of decline. This cognitive inertia at the individual and corporate level has been proposed as reasons to why companies do not adopt new strategies to combat the ever-increasing decline in the business or take advantage of the potential. General Mills' continued operation of mills long after they were no longer necessary is an example of when companies refuse to change the mindset of how they should operate.
+More famously, cognitive inertia in upper management at Polaroid was proposed as one of the main contributing factors to the company's outdated competitive strategy. Management strongly held that consumers wanted high-quality physical copies of their photos, where the company would make their money. Despite Polaroid's extensive research and development into the digital market, their inability to refocus their strategy to hardware sales instead of film eventually led to their collapse.
+Scenario planning has been one suggestion to combat cognitive inertia when making strategic decisions to improve business. Individuals develop different strategies and outline how the scenario could play out, considering different ways it could go. Scenario planning allows for diverse ideas to be heard and the breadth of each scenario, which can help combat relying on existing methods and thinking alternatives is unrealistic.
+
+=== Management ===
+In a recent review of company archetypes that lead to corporate failure, Habersang, Küberling, Reihlen, and Seckler defined "the laggard" as one who rests on the laurels of the company, believing past success and recognition will shield them from failure. Instead of adapting to changes in the market, "the laggard" assumes that the same strategies that won the company success in the past will do the same in the future. This lag in changing how they think about the company can lead to rigidity in company identity, like Polaroid, conflict in adapting when the sales plummet, and resource rigidity. In the case of Kodak, instead of reallocating money to a new product or service strategy, they cut production costs and imitation of competitors, both leading to poorer quality products and eventually bankruptcy.
+A review of 27 firms integrating the use of big data analytics found cognitive inertia to hamper the widespread implementation, with managers from sectors that did not focus on digital technology seeing the change as unnecessary and cost prohibitive.
+Managers with high cognitive flexibility that can change the type of cognitive processing based on the situation at hand are often the most successful in solving novel problems and keeping up with changing circumstances. Interestingly, shifts in mental models (disrupting cognitive inertia) during a company crisis are frequently at the lower group level, with leaders coming to a consensus with the rest of the workforce in how to process and deal with the crisis, instead of vice versa. It is proposed that leaders can be blinded by their authority and too easily disregard those at the front-line of the problem causing them to reject remunerative ideas.
+
+== Applications ==
+
+=== Therapy ===
+An inability to change how one thinks about a situation has been implicated as one of the causes of depression. Rumination, or the perseverance of negative thoughts, is often correlated with the severity of depression and anxiety. Individuals with high levels of rumination test low on scales of cognitive flexibility and have trouble shifting how they think about a problem or issue even when presented with facts that counter their thinking process.
+In a review paper that outlined strategies that are effective for combating depression, the Socratic method was suggested to overcome cognitive inertia. By presenting the patient's incoherent beliefs close together and evaluating with the patient their thought processes behind those beliefs, the therapist is able to help them understand things from a different perspective.

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+title: "Cognitive inertia"
+chunk: 4/4
+source: "https://en.wikipedia.org/wiki/Cognitive_inertia"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:22.921691+00:00"
+instance: "kb-cron"
+---
+
+=== Clinical diagnostics ===
+In nosological literature relating to the symptom or disorder of apathy, clinicians have used cognitive inertia as one of the three main criteria for diagnosis. The description of cognitive inertia differs from its use in cognitive and industrial psychology in that lack of motivation plays a key role. As a clinical diagnostic criterion, Thant and Yager described it as "impaired abilities to elaborate and sustain goals and plans of actions, to shift mental sets, and to use working memory". This definition of apathy is frequently applied to onset of apathy due to neurodegenerative disorders such as Alzheimer's and Parkinson's disease but has also been applied to individuals who have gone through extreme trauma or abuse.
+
+== Neural anatomy and correlates ==
+
+=== Cortical ===
+Cognitive inertia has been linked to decreased use of executive function, primarily in the prefrontal cortex, which aids in the flexibility of cognitive processes when switching tasks. Delayed response on the implicit associations task (IAT) and Stroop task have been related to an inability to combat cognitive inertia, as participants struggle to switch from one cognitive rule to the next to get the questions right.
+Before taking part in an electronic brainstorming session, participants were primed with pictures that motivated achievement to combat cognitive inertia. In the achievement-primed condition, subjects were able to produce more novel, high-quality ideas. They used more right frontal cortical areas related to decision-making and creativity.
+Cognitive inertia is a critical dimension of clinical apathy, described as a lack of motivation to elaborate plans for goal-directed behavior or automated processing. Parkinson's patients whose apathy was measured using the cognitive inertia dimension showed less executive function control than Parkinson's patients without apathy, possibly suggesting more damage to the frontal cortex. Additionally, more damage to the basal ganglia in Parkinson's, Huntington's and other neurodegenerative disorders have been found with patients exhibiting cognitive inertia in relation to apathy when compared to those who do not exhibit apathy. Patients with lesions to the dorsolateral prefrontal cortex have shown reduced motivation to change cognitive strategies and how they view situations, similar to individuals who experience apathy and cognitive inertia after severe or long-term trauma.
+
+=== Functional connectivity ===
+Nursing home patients who have dementia have been found to have larger reductions in functional brain connectivity, primarily in the corpus callosum, important for communication between hemispheres. Cognitive inertia in neurodegenerative patients has also been associated with a decrease in the connection of the dorsolateral prefrontal cortex and posterior parietal area with subcortical areas, including the anterior cingulate cortex and basal ganglia. Both findings are suggested to decrease motivation to change one's thought processes or create new goal-directed behavior.
+
+== Alternative theories ==
+Some researchers have refuted the cognitive perspective of cognitive inertia and suggest a more holistic approach that considers the motivations, emotions, and attitudes that fortify the existing frame of reference.
+
+=== Alternative paradigms ===
+
+==== Motivated reasoning ====
+The theory of motivated reasoning is proposed to be driven by the individual's motivation to think a certain way, often to avoid thinking negatively about oneself. The individual's own cognitive and emotional biases are commonly used to justify a thought, belief, or behavior. Unlike cognitive inertia, where an individual's orientation in processing information remains unchanged either due to new information not being fully absorbed or being blocked by a cognitive bias, motivated reasoning may change the orientation or keep it the same depending on whether that orientation benefits the individual.
+In an extensive online study, participant opinions were acquired after two readings about various political issues to assess the role of cognitive inertia. The participants gave their opinions after the first reading and were then assigned a second reading with new information; after being assigned to read more information on the issue that either confirmed or disconfirmed their initial opinion, the majority of participants' opinions did not change. When asked about the information in the second reading, those who did not change their opinion evaluated the information that supported their initial opinion as stronger than information that disconfirmed their initial opinion. The persistence in how the participants viewed the incoming information was based on their motivation to be correct in their initial opinion, not the persistence of an existing cognitive perspective.
+
+==== Socio-cognitive inflexibility ====
+From a social psychology perspective, individuals continually shape beliefs and attitudes about the world based on interaction with others. What information the individual attends to is based on prior experience and knowledge of the world. Cognitive inertia is seen not just as a malfunction in updating how information is being processed but as the assumptions about the world and how it works can impede cognitive flexibility. The persistence of the idea of the nuclear family has been proposed as a socio-cognitive inertia. Despite the changing trends in family structure, including multi-generational, single-parent, blended, and same-sex parent families, the normative idea of a family has centered around the mid-twentieth century idea of a nuclear family (i.e., mother, father, and children). Various social influences are proposed to maintain the inertia of this viewpoint, including media portrayals, the persistence of working-class gender roles, unchanged domestic roles despite working mothers, and familial pressure to conform.
+The phenomenon of cognitive inertia in brainstorming groups has been argued to be due to other psychological effects such as fear of disagreeing with an authority figure in the group, fear of new ideas being rejected and the majority of speech being attributed to the minority group members. Internet-based brainstorming groups have been found to produce more ideas of high-quality because it overcomes the problem of speaking up and fear of idea rejection.    
+
+== See also ==
+
+== References ==

data/en.wikipedia.org/wiki/Compression_of_morbidity-0.md

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+title: "Compression of morbidity"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Compression_of_morbidity"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:14.618203+00:00"
+instance: "kb-cron"
+---
+
+The compression of morbidity in public health is a hypothesis put forth by James Fries, professor of medicine at Stanford University School of Medicine. The hypothesis was supported by a 1998 study of 1700 University of Pennsylvania alumni over a period of 20 years.
+Fries' hypothesis is that the burden of lifetime illness may be compressed into a shorter period before the time of death, if the age of onset of the first chronic infirmity can be postponed. This hypothesis contrasts to the view that as the age of countries' populations tends to increase over time, they will become increasingly infirm and consume an ever-larger proportion of the national budget in healthcare costs.
+Fries posited that if the hypothesis is confirmed, healthcare costs and patient health overall will be improved. In order to confirm this hypothesis, the evidence must show that it is possible to delay the onset of infirmity, and that corresponding increases in longevity will at least be modest. The evidence is at best mixed.  Vincent Mor's "The Compression of Morbidity Hypothesis: A Review of Research and Prospects for the Future" argues that "Cross-national evidence for the validity of the compression of morbidity hypothesis originally proposed by Fries is generally accepted. Generational improvements in education and the increased availability of adaptive technologies and even medical treatments that enhance quality of life have facilitated continued independence of older persons in the industrialized world. Whether this trend continues may depend upon the effect of the obesity epidemic on the next generation of older people." See also "Mortality and Morbidity Trends: Is There Compression of Morbidity?" for recent evidence against the hypothesis.
+There may also be age versus cohort effects.
+
+
+== See also ==
+Successful aging
+
+
+== References ==
+
+
+== Further reading ==
+Fries, James F. (2005). "The Compression of Morbidity". The Milbank Quarterly. 83 (4): 801–23. doi:10.1111/j.1468-0009.2005.00401.x. PMC 2690269. PMID 16279968.
+Brody, Jane E. (August 25, 2008). "Living Longer, in Good Health to the End". The New York Times. p. D7.
+Gretchen Reynolds (8 February 2017) "Lessons on Aging Well from a 105-Year-Old Cyclist" The New York Times accessdate=2017-02-14

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+title: "Computational heuristic intelligence"
+chunk: 1/1
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+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:24.198634+00:00"
+instance: "kb-cron"
+---
+
+Computational heuristic intelligence (CHI) refers to specialized programming techniques in computational intelligence (also called artificial intelligence, or AI). These techniques have the express goal of avoiding complexity issues, also called NP-hard problems, by using human-like techniques. They are best summarized as the use of exemplar-based methods (heuristics), rather than rule-based methods (algorithms). Hence the term is distinct from the more conventional computational algorithmic intelligence, or symbolic AI. An example of a CHI technique is the encoding specificity principle of Tulving and Thompson. In general, CHI principles are problem solving techniques used by people, rather than programmed into machines. It is by drawing attention to this key distinction that the use of this term is justified in a field already replete with confusing neologisms. Note that the legal systems of all modern human societies employ both heuristics (generalisations of cases) from individual trial records as well as legislated statutes (rules) as regulatory guides.
+Another recent approach to the avoidance of complexity issues is to employ feedback control rather than feedforward modeling as a problem-solving paradigm. This approach has been called computational cybernetics, because (a) the term 'computational' is associated with conventional computer programming techniques which represent a strategic, compiled, or feedforward model of the problem, and (b) the term 'cybernetic' is associated with conventional system operation techniques which represent a tactical, interpreted, or feedback model of the problem. Of course, real programs and real problems both contain both feedforward and feedback components. A real example which illustrates this point is that of human cognition, which clearly involves both perceptual (bottom-up, feedback, sensor-oriented) and conceptual (top-down, feedforward, motor-oriented) information flows and hierarchies.
+The AI engineer must choose between mathematical and cybernetic problem solution and machine design paradigms. This is not a coding (program language) issue, but relates to understanding the relationship between the declarative and procedural programming paradigms. 
+The vast majority of STEM professionals never get the opportunity to design or implement pure cybernetic solutions. When pushed, most responders will dismiss the importance of any difference by saying that all code can be reduced to a mathematical model anyway. Unfortunately, not only is this belief false, it fails most spectacularly in many AI scenarios.
+Mathematical models are not time agnostic, but by their very nature are pre-computed, i.e. feedforward. Dyer [2012] and Feldman [2004] have independently investigated the simplest of all somatic governance paradigms, namely control of a simple jointed limb by a single flexor muscle. They found that it is impossible to determine forces from limb positions- therefore, the problem cannot have a pre-computed (feedforward) mathematical solution. Instead, a top-down command bias signal changes the threshold feedback level in the sensorimotor loop, e.g. the loop formed by the afferent and efferent nerves, thus changing the so-called ‘equilibrium point’ of the flexor muscle/ elbow joint system. An overview of the arrangement reveals that global postures and limb position are commanded in feedforward terms, using global displacements (common coding), with the forces needed being computed locally by feedback loops. This method of sensorimotor unit governance, which is based upon what Anatol Feldman calls the ‘equilibrium Point’ theory, is formally equivalent to a servomechanism such as a car's ‘cruise control’.
+
+
+== See also ==
+NP-hard
+Heuristics
+Computational cybernetics
+Top-down and bottom-up design
+
+
+== References ==

data/en.wikipedia.org/wiki/Consistent_heuristic-0.md

@@ -0,0 +1,581 @@
+---
+title: "Consistent heuristic"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Consistent_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:25.369916+00:00"
+instance: "kb-cron"
+---
+
+In the study of path-finding problems in artificial intelligence, a heuristic function is said to be consistent, or monotone, if its estimate is always less than or equal to the estimated distance from any neighbouring vertex to the goal, plus the cost of reaching that neighbour.
+Formally, for every node N and each successor P of N, the estimated cost of reaching the goal from N is no greater than the step cost of getting to P plus the estimated cost of reaching the goal from P. That is:
+
+  
+    
+      
+        h
+        (
+        N
+        )
+        ≤
+        c
+        (
+        N
+        ,
+        P
+        )
+        +
+        h
+        (
+        P
+        )
+      
+    
+    {\displaystyle h(N)\leq c(N,P)+h(P)}
+  
+ and
+
+  
+    
+      
+        h
+        (
+        G
+        )
+        =
+        0.
+        
+      
+    
+    {\displaystyle h(G)=0.\,}
+  
+
+where
+
+h is the consistent heuristic function
+N is any node in the graph
+P is any descendant of N
+G is any goal node
+c(N,P) is the cost of reaching node P from N
+Informally, every node i will give an estimate that, accounting for the cost to reach the next node, is always lesser than or equal to the estimate at node i+1.
+A consistent heuristic is also admissible, i.e. it never overestimates the cost of reaching the goal (the converse, however, is not always true). Assuming non negative edges, this can be easily proved by induction.
+Let 
+  
+    
+      
+        h
+        (
+        
+          N
+          
+            0
+          
+        
+        )
+        =
+        0
+      
+    
+    {\displaystyle h(N_{0})=0}
+  
+ be the estimated cost for the goal node. This implies that the base condition is trivially true as 0 ≤ 0. Since the heuristic is consistent, 
+  
+    
+      
+        h
+        (
+        
+          N
+          
+            i
+            +
+            1
+          
+        
+        )
+        ≤
+        c
+        (
+        
+          N
+          
+            i
+            +
+            1
+          
+        
+        ,
+        
+          N
+          
+            i
+          
+        
+        )
+        +
+        h
+        (
+        
+          N
+          
+            i
+          
+        
+        )
+        ≤
+        c
+        (
+        
+          N
+          
+            i
+            +
+            1
+          
+        
+        ,
+        
+          N
+          
+            i
+          
+        
+        )
+        +
+        c
+        (
+        
+          N
+          
+            i
+          
+        
+        ,
+        
+          N
+          
+            i
+            −
+            1
+          
+        
+        )
+        +
+        .
+        .
+        .
+        +
+        c
+        (
+        
+          N
+          
+            1
+          
+        
+        ,
+        
+          N
+          
+            0
+          
+        
+        )
+        +
+        h
+        (
+        
+          N
+          
+            0
+          
+        
+        )
+      
+    
+    {\displaystyle h(N_{i+1})\leq c(N_{i+1},N_{i})+h(N_{i})\leq c(N_{i+1},N_{i})+c(N_{i},N_{i-1})+...+c(N_{1},N_{0})+h(N_{0})}
+  
+ by expansion of each term. The given terms are equal to the true cost, 
+  
+    
+      
+        
+          ∑
+          
+            i
+            =
+            1
+          
+          
+            n
+          
+        
+        c
+        (
+        
+          N
+          
+            i
+          
+        
+        ,
+        
+          N
+          
+            i
+            −
+            1
+          
+        
+        )
+      
+    
+    {\displaystyle \sum _{i=1}^{n}c(N_{i},N_{i-1})}
+  
+, so any consistent heuristic is also admissible since it is upperbounded by the true cost.
+The converse is clearly not true as we can always construct a heuristic that is always below the true cost but is nevertheless inconsistent by, for instance, increasing the heuristic estimate from the farthest node as we get closer and, when the estimate 
+  
+    
+      
+        h
+        (
+        
+          N
+          
+            i
+          
+        
+        )
+      
+    
+    {\displaystyle h(N_{i})}
+  
+ becomes at most the true cost 
+  
+    
+      
+        
+          h
+          
+            ∗
+          
+        
+        (
+        
+          N
+          
+            i
+          
+        
+        )
+      
+    
+    {\displaystyle h^{*}(N_{i})}
+  
+, we make 
+  
+    
+      
+        h
+        (
+        
+          N
+          
+            i
+            −
+            1
+          
+        
+        )
+        =
+        h
+        (
+        
+          N
+          
+            i
+          
+        
+        )
+        −
+        c
+        (
+        
+          N
+          
+            i
+          
+        
+        ,
+        
+          N
+          
+            i
+            −
+            1
+          
+        
+        )
+      
+    
+    {\displaystyle h(N_{i-1})=h(N_{i})-c(N_{i},N_{i-1})}
+  
+.
+
+== Consequences of monotonicity ==
+
+Consistent heuristics are called monotone because the estimated final cost of a partial solution, 
+  
+    
+      
+        f
+        (
+        
+          N
+          
+            j
+          
+        
+        )
+        =
+        g
+        (
+        
+          N
+          
+            j
+          
+        
+        )
+        +
+        h
+        (
+        
+          N
+          
+            j
+          
+        
+        )
+      
+    
+    {\displaystyle f(N_{j})=g(N_{j})+h(N_{j})}
+  
+ is monotonically non-decreasing along any path, where 
+  
+    
+      
+        g
+        (
+        
+          N
+          
+            j
+          
+        
+        )
+        =
+        
+          ∑
+          
+            i
+            =
+            2
+          
+          
+            j
+          
+        
+        c
+        (
+        
+          N
+          
+            i
+            −
+            1
+          
+        
+        ,
+        
+          N
+          
+            i
+          
+        
+        )
+      
+    
+    {\displaystyle g(N_{j})=\sum _{i=2}^{j}c(N_{i-1},N_{i})}
+  
+ is the cost of the best path from start node 
+  
+    
+      
+        
+          N
+          
+            1
+          
+        
+      
+    
+    {\displaystyle N_{1}}
+  
+ to 
+  
+    
+      
+        
+          N
+          
+            j
+          
+        
+      
+    
+    {\displaystyle N_{j}}
+  
+.  It's necessary and sufficient for a heuristic to obey the triangle inequality in order to be consistent.
+The justification for 
+  
+    
+      
+        f
+        (
+        N
+        )
+      
+    
+    {\displaystyle f(N)}
+  
+ to be monotonically non-decreasing under a consistent heuristic is as follows:
+Suppose 
+  
+    
+      
+        P
+      
+    
+    {\displaystyle P}
+  
+ is a successor of 
+  
+    
+      
+        N
+      
+    
+    {\displaystyle N}
+  
+, then  
+  
+    
+      
+        g
+        (
+        P
+        )
+        =
+        g
+        (
+        N
+        )
+        +
+        c
+        (
+        N
+        ,
+        a
+        ,
+        P
+        )
+      
+    
+    {\displaystyle g(P)=g(N)+c(N,a,P)}
+  
+ for some action 
+  
+    
+      
+        a
+      
+    
+    {\displaystyle a}
+  
+ from 
+  
+    
+      
+        N
+      
+    
+    {\displaystyle N}
+  
+ to 
+  
+    
+      
+        P
+      
+    
+    {\displaystyle P}
+  
+. Then we have that
+
+  
+    
+      
+        f
+        (
+        P
+        )
+        =
+        g
+        (
+        P
+        )
+        +
+        h
+        (
+        P
+        )
+        =
+        g
+        (
+        N
+        )
+        +
+        c
+        (
+        N
+        ,
+        a
+        ,
+        P
+        )
+        +
+        h
+        (
+        P
+        )
+        ≥
+        g
+        (
+        N
+        )
+        +
+        h
+        (
+        N
+        )
+        =
+        f
+        (
+        N
+        )
+      
+    
+    {\displaystyle f(P)=g(P)+h(P)=g(N)+c(N,a,P)+h(P)\geq g(N)+h(N)=f(N)}
+  

data/en.wikipedia.org/wiki/Consistent_heuristic-1.md

@@ -0,0 +1,374 @@
+---
+title: "Consistent heuristic"
+chunk: 2/2
+source: "https://en.wikipedia.org/wiki/Consistent_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:25.369916+00:00"
+instance: "kb-cron"
+---
+
+hence 
+  
+    
+      
+        f
+        (
+        P
+        )
+        ≥
+        f
+        (
+        N
+        )
+      
+    
+    {\displaystyle f(P)\geq f(N)}
+  
+.
+In the A* search algorithm, using a consistent heuristic means that once a node is expanded, the cost by which it was reached is the lowest possible, under the same conditions that Dijkstra's algorithm requires in solving the shortest path problem (no negative cost edges).  In fact, if the search graph is given cost 
+  
+    
+      
+        
+          c
+          ′
+        
+        (
+        N
+        ,
+        P
+        )
+        =
+        c
+        (
+        N
+        ,
+        P
+        )
+        +
+        h
+        (
+        P
+        )
+        −
+        h
+        (
+        N
+        )
+      
+    
+    {\displaystyle c'(N,P)=c(N,P)+h(P)-h(N)}
+  
+ for a consistent 
+  
+    
+      
+        h
+      
+    
+    {\displaystyle h}
+  
+, then A* is equivalent to best-first search on that graph using Dijkstra's algorithm.
+With a non-decreasing 
+  
+    
+      
+        f
+        (
+        N
+        )
+      
+    
+    {\displaystyle f(N)}
+  
+ under consistent heuristics, one can show that A* achieves optimality with cycle-checking, that is, when A* expands a node 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+, the optimal path to 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+ has already been found. Suppose for the sake of contradiction that when A* expands 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+, the optimal path has not been found. Then, by the graph separation property, there must exist another node 
+  
+    
+      
+        
+          n
+          ′
+        
+      
+    
+    {\displaystyle n'}
+  
+ on the optimal path to 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+ on the frontier. Since 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+ was selected for expansion instead of 
+  
+    
+      
+        
+          n
+          ′
+        
+      
+    
+    {\displaystyle n'}
+  
+, this would mean that 
+  
+    
+      
+        f
+        (
+        n
+        )
+        <
+        f
+        (
+        
+          n
+          ′
+        
+        )
+      
+    
+    {\displaystyle f(n)<f(n')}
+  
+. But since f-values are monotonically non-decreasing along any path under the consistent heuristic function 
+  
+    
+      
+        f
+      
+    
+    {\displaystyle f}
+  
+ , we know that 
+  
+    
+      
+        f
+        (
+        n
+        )
+        ≥
+        f
+        (
+        
+          n
+          ′
+        
+        )
+      
+    
+    {\displaystyle f(n)\geq f(n')}
+  
+ since 
+  
+    
+      
+        
+          n
+          ′
+        
+      
+    
+    {\displaystyle n'}
+  
+ is on the path to 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+. This is a contradiction, meaning that 
+  
+    
+      
+        
+          n
+          ′
+        
+      
+    
+    {\displaystyle n'}
+  
+ should have been selected for expansion first instead of 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+.
+In the unusual event that an admissible heuristic is not consistent, a node will need repeated expansion every time a new best (so-far) cost is achieved for it.
+If the given heuristic 
+  
+    
+      
+        h
+      
+    
+    {\displaystyle h}
+  
+ is admissible but not consistent, one can artificially force the heuristic values along a path to be monotonically non-decreasing
+by using 
+
+  
+    
+      
+        
+          h
+          ′
+        
+        (
+        P
+        )
+        ←
+        max
+        (
+        h
+        (
+        P
+        )
+        ,
+        
+          h
+          ′
+        
+        (
+        N
+        )
+        −
+        c
+        (
+        N
+        ,
+        P
+        )
+        )
+      
+    
+    {\displaystyle h'(P)\gets \max(h(P),h'(N)-c(N,P))}
+  
+
+as the heuristic value for 
+  
+    
+      
+        P
+      
+    
+    {\displaystyle P}
+  
+ instead of 
+  
+    
+      
+        h
+        (
+        P
+        )
+      
+    
+    {\displaystyle h(P)}
+  
+, where 
+  
+    
+      
+        N
+      
+    
+    {\displaystyle N}
+  
+ is the node immediately preceding 
+  
+    
+      
+        P
+      
+    
+    {\displaystyle P}
+  
+ on the path and 
+  
+    
+      
+        
+          h
+          ′
+        
+        (
+        s
+        t
+        a
+        r
+        t
+        )
+        =
+        h
+        (
+        s
+        t
+        a
+        r
+        t
+        )
+      
+    
+    {\displaystyle h'(start)=h(start)}
+  
+. This idea is due to László Mérō
+and is now known as pathmax.
+Contrary to common belief, pathmax does not turn an admissible heuristic into a consistent heuristic. For example, if A* uses pathmax and a heuristic that is admissible but not consistent, it is not guaranteed to have an optimal path to a node when it is first expanded.
+
+=== Relation to Local Admissibility ===
+Modifying the consistency condition to h(N)−h(P) ≤ c(N,P) establishes a connection to local admissibility, where the heuristic estimate to a specific node remains less than or equal to the actual step cost. This ensures optimality when selecting local nodes, akin to how admissible heuristics ensure global optimality. By maintaining this property, the search process improves efficiency by making locally optimal decisions that contribute to the globally optimal solution.
+
+== See also ==
+Admissible heuristic
+
+== References ==

data/en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids-0.md

@@ -0,0 +1,30 @@
+---
+title: "Construction of the Egyptian pyramids"
+chunk: 1/5
+source: "https://en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:22.840815+00:00"
+instance: "kb-cron"
+---
+
+The construction of the Egyptian pyramids can be explained with well-established scientific facts; however, there are some aspects that even today are considered controversial hypotheses. The construction techniques used seem to have developed over time; later pyramids were not constructed in the same way as earlier ones. It is believed that huge stones were carved from quarries with copper tools, and these blocks were then dragged and lifted into position. Disagreements chiefly concern the methods used to move and place the stones.
+In addition to the many unresolved arguments about the construction techniques, there have been many disagreements as to the kind of workforce used. The Greeks, many years after the event, believed that the pyramids were built by slave labour. Archaeologists now believe that the Great Pyramid of Giza (at least) was built by tens of thousands of skilled workers who camped near the pyramids and worked for a salary or as a form of tax payment (levy) until the construction was completed, pointing to workers' cemeteries discovered in 1990. For the Middle Kingdom pyramid of Amenemhat II, there is evidence from the annal stone of the king that foreigners from Canaan were employed.
+The pseudoscientific field of pyramidology includes many archaeological fringe theories attempting to explain how the pyramids were built.
+
+== Historical hypotheses ==
+
+=== The Writing of Herodotus and Diodorus Siculus ===
+The first historical accounts of the construction of these monuments came centuries after the era of pyramid construction, by Herodotus in the 5th century BC and Diodorus Siculus in the 1st century BC. Herodotus's account claims that the Egyptians used a machine (now referred to as the "Herodotus Machine"), stating:
+
+This pyramid was made like stairs, which some call steps and others, tiers. When this, its first form, was completed, the workmen used short wooden logs as levers to raise the rest of the stones; they heaved up the blocks from the ground onto the first tier of steps; when the stone had been raised, it was set on another lever that stood on the first tier, and the lever again used to lift it from this tier to the next. It may be that there was a new lever on each tier of steps, or perhaps there was only one lever, quite portable, which they carried up to each tier in turn; I leave this uncertain, as both possibilities were mentioned. But this is certain, that the upper part of the pyramid was finished off first, then the next below it, and last of all the base and the lowest part. 
+Diodorus Siculus's account states:
+
+And it's said the stone was transported a great distance from Arabia, and that the edifices were raised utilizing earthen ramps since machines for lifting had not yet been invented in those days; and most surprising it is, that although such large structures were raised in an area surrounded by sand, no trace remains of either ramps or the dressing of the stones, so that it seems not the result of the patient labour of men, but rather as if the whole complex were set down entire upon the surrounding sand by some god. Now Egyptians try to make a marvel of these things, alleging that the ramps were made of salt and natron and that, when the river was turned against them, it melted them clean away and obliterated their every trace without the use of human labour. But in truth, it most certainly was not done this way! Rather, the same multitude of workmen who raised the mounds returned the entire mass to its original place; for they say that three hundred and sixty thousand men were constantly employed in the prosecution of their work, yet the entire edifice was hardly finished at the end of twenty years.
+Diodorus Siculus's description of the shipment of the stone from Arabia is correct since the term "Arabia" in those days implied the land between the Nile and the Red Sea where the limestone blocks have been transported from quarries across the river Nile.
+
+=== Third through Fifth dynasties ===
+During the earliest period, pyramids were constructed wholly of stone. Locally quarried limestone was the material of choice for the main body of these pyramids, while a higher quality of limestone quarried at Tura (near modern Cairo) was used for the outer casing. The limestone originated from different outcrops of the Eocene-aged Mokattam Formation. Granite, quarried near Aswan, was used to construct some architectural elements, including the portcullis (a type of gate) and the roofs and walls of the burial chamber. Occasionally, granite was used in the outer casing as well, such as in the Pyramid of Menkaure. In the early pyramids, the layers of stone (called courses) forming the pyramid body were laid sloping inwards; however, this configuration was abandoned in later pyramids. The Bent Pyramid at Dahshur seems to indicate acceptance of a new technique at a transition between these two building techniques. Its lower section is built of sloping courses while in its upper section the stones are laid horizontally.
+
+=== Middle Kingdom and onward ===
+During the Middle Kingdom, pyramid construction techniques changed again. Most pyramids built then were little more than mountains of mud-brick encased in a veneer of polished limestone. In several cases, later pyramids were built on top of natural hills to further reduce the volume of material needed in their construction. The materials and methods of construction used in the earliest pyramids have ensured their survival in a generally much better state of preservation than for the pyramid monuments of the later pharaohs.

data/en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids-1.md

@@ -0,0 +1,26 @@
+---
+title: "Construction of the Egyptian pyramids"
+chunk: 2/5
+source: "https://en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:22.840815+00:00"
+instance: "kb-cron"
+---
+
+=== Mortar ===
+The stones forming the core of the pyramids were roughly cut, especially in the Great Pyramid. To fill the gaps, huge quantities of gypsum and rubble were needed.  The filling has almost no binding properties, but it was necessary to stabilize the construction. To make the gypsum mortar, it had to be dehydrated by heating which requires large quantities of wood. According to Egyptologists, the findings of both the 1984 and 1995 David H. Koch Pyramids Radiocarbon Projects may suggest that Egypt had to strip its forest and scrap every bit of wood it had to build the pyramids of Giza and other even earlier 4th Dynasty pyramids. Carbon dating samples from core blocks and other materials revealed that dates from the 1984 study averaged 374 years earlier than currently accepted and the 1995 dating averaging 100–200 years. As suggested by team members, "We thought that it was unlikely that the pyramid builders consistently used centuries-old wood as fuel in preparing mortar. The 1984 results left us with too little data to conclude that the historical chronology of the Old Kingdom was wrong by nearly 400 years, but we considered this at least a possibility". Egyptologists propose that the old wood problem is responsible for the discrepancy, claiming the earlier dates were possibly derived from recycling large amounts of centuries-old wood and other earlier materials.
+
+=== Arsenical copper ===
+The main material used in the Old and Middle Kingdoms was so-called arsenical copper or bronze. It is more effective than copper with minor impurities, and can be made even harder by repeated hammering.  Hundreds of artefacts from these periods were made of this material. All preserved copper alloy tools of the Old Kingdom era of pyramid builders were recently collected in a monograph. Its occurrence was also confirmed for the settlement material from Giza, from the reigns of Khufu and Khafre. Recent data from Middle Kingdom Elephantine Island indicate that this material was an intentionally produced alloy, and a result of rather complex technology.
+
+== Quarrying ==
+There is good information concerning the location of the quarries, some of the tools used to cut stone in the quarries, transportation of the stone to the monument, leveling the foundation, and leveling the subsequent tiers of the developing superstructure. Workmen probably used copper chisels, drills, and saws to cut softer stone, such as most of the limestone. The harder stones, such as granite, granodiorite, syenite, and basalt, cannot be cut with copper tools alone; instead, they were worked with time-consuming methods like pounding with dolerite, drilling, and sawing with the aid of an abrasive, such as quartz or corundum sand. This occurred in a process known as sand abrasion. Blocks were transported by sledge likely lubricated by water.
+Leveling the foundation may have been accomplished by use of water-filled trenches as suggested by Mark Lehner and I. E. S. Edwards or through the use of a crude square level and experienced surveyors. 
+
+== Transport of stone blocks ==
+
+One of the major problems faced by the early pyramid builders was the need to move immense quantities of stone. The Twelfth Dynasty tomb of Djehutihotep has an illustration of 172 men pulling an alabaster statue of him on a sledge. The statue is estimated to weigh 60 tons and Denys Stocks estimated that 45 workers would be required to start moving a 16,300 kg (35,900 lb) lubricated block, or eight workers to move a 2,750 kg (6,060 lb) block. Dick Parry and Mladjov have suggested a method for rolling the stones, using a cradle-like machine that had been excavated in various new kingdom temples. Four of those objects could be fitted around a block so it could be rolled easily. Experiments done by the Obayashi Corporation, with concrete blocks 0.8 metres (2 ft 7 in) square by 1.6 metres (5 ft 3 in) long and weighing 2.5 tonnes (5,500 lb), showed how 18 men could drag the block over a 1-in-4 incline ramp, at a rate of 18 metres per minute (1 ft/s; 1 km/h). This idea was previously described by John Bush in 1977, and is mentioned in the Closing Remarks section of Parry's book. Vitruvius in De architectura described a similar method for moving irregular weights. It is still not known whether the Egyptians used this method but the experiments indicate it could have worked using stones of this size. Egyptologists generally accept this for the 2.5 ton blocks mostly used but do not agree over the methods used for the 15+ ton and several 70 to 80 ton blocks.
+The diary of Merer, logbooks written more than 4,500 years ago by an Egyptian official and found in 2013 by a French archeology team under the direction of Pierre Tallet in a cave in Wadi al-Jarf, describes the transportation of limestone blocks from the quarries at Tura to Giza by boat.
+
+=== Ramps ===

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+---
+title: "Construction of the Egyptian pyramids"
+chunk: 3/5
+source: "https://en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:22.840815+00:00"
+instance: "kb-cron"
+---
+
+Most Egyptologists acknowledge that ramps are the most tenable of the methods to raise the blocks, yet they acknowledge that it is an incomplete method that must be supplemented by another device. Archaeological evidence for the use of ramps has been found at the Great Pyramid of Giza and other pyramids. The method most accepted for assisting ramps is levering. The archaeological record gives evidence of only small ramps and inclined causeways, not something that could have been used to construct even a majority of the monument. To add to the uncertainty, there is considerable evidence demonstrating that non-standardized or ad hoc construction methods were used in pyramid construction.
+Therefore, there are many proposed ramps and there is a considerable amount of discrepancy regarding what type of ramp was used to build the pyramids. One of the widely discredited ramping methods is the large straight ramp, and it is routinely discredited on functional grounds for its massive size, lack of archaeological evidence, huge labor cost, and other problems.
+Other ramps serve to correct these problems of ramp size, yet run into critiques of either functionality or limited archaeological evidence. Zig-zagging ramps, straight ramps using the incomplete part of the superstructure (Arnold 1991), spiraling ramps supported by the superstructure and spiraling ramps leaning on the monument as a large accretion have been proposed. Mark Lehner speculated that a spiraling ramp, beginning in the stone quarry to the southeast and continuing around the exterior of the pyramid, may have been used. However, spiral ramps would have covered the building for decades fully and would not allow the regular layout of the exact pyramid square in equal distance to each base cornerstone as the only method to keep the exact geometric shape of the edges and side mantles. Ramp models with several ramp paths, which are positioned on the inner step pyramid require relatively less material. The stone blocks may have been drawn on sleds along the ramps lubricated by water.
+As a recent study shows that the challenge was not just to account for the route the transported stones had to take but to account for the size and frequency of stones being moved—circa 1 ton being put in place every 2–3 minutes by human draw teams on a ramp of maximum 10%—to enable building of the Great Pyramid within 30 years. The special case of the pyramid extensions E2 and E3 in Meydum of ring-shaped extensions only 5 metres (16 ft) wide around the previous building core shows the ramp system was effective and small in volume which applies for tangential ramps of 10 cubits or 5 metre width. The challenge was the geometry of the pyramid that provides shorter side lengths the higher the building grows, increases the necessity to turn maneuvers and allows less space for ramps leaning on the masonry. The slope change of the Bent Pyramid is probably the result of the discovery this can not be solved with steep gradients. Also essential was the effective organization of the building site by a module that allowed the work division of the teams along plots and the transport causeways between ramp and workplace, including the return of pulling crews and sleds, probably by a second ramp system. The problem of building the mantle at the ramp arrival point could be solved by bypass-systems.
+
+=== Levering ===
+Levering methods are considered to be the most tenable solution to complement ramping methods, partially due to Herodotus's description; and partially to the shadoof, a lever-enabled irrigation device first depicted in Egypt during the New Kingdom and found concomitantly with the Old Kingdom in Mesopotamia. In Lehner's point of view, levers should be employed to lift the top 3% of the material of the superstructure. It is important to note that the top 4% of this material comprises 1⁄3 of the total height of the monument. In other words, in Lehner's view, levers should be employed to lift a small amount of material and a great deal of vertical height of the monument.
+In the milieu of levering methods, there are those that lift the block incrementally, as in repeatedly prying up alternating sides of the block and inserting wooden or stone shims to gradually move the stone up one course; and there are other methods that use a larger lever to move the block up one course in one lifting procedure. Since the discussion of construction techniques to lift the blocks attempts to resolve a gap in the archaeological and historical record with a plausible functional explanation, the following examples by Isler, Keable, and Hussey-Pailos list experimentally tested methods. Isler's method (1985, 1987) is an incremental method and, in the Nova experiment (1992), used wooden shims or cribbing. Isler was able to lift a block up one tier in approximately one hour and 30 minutes. Peter Hodges and Julian Keable's method is similar to Isler's method and instead used small manufactured concrete blocks as shims, wooden pallets, and a pit where their experimental tests were performed. Keable was able to perform his method in approximately 2 minutes. Scott Hussey-Pailos's (2005) method uses a simple levering device to lift a block up a course in one movement. This method was tested with materials of less strength than historical analogs (tested with materials weaker than those available in ancient Egypt), a factor of safety of 2, and lifted a 1,100 kg (2,500 lb) block up one course in under a minute. This method is presented as a levering device to work complementary with Mark Lehner's idea of a combined ramp and levering techniques.

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+---
+title: "Construction of the Egyptian pyramids"
+chunk: 4/5
+source: "https://en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:22.840815+00:00"
+instance: "kb-cron"
+---
+
+=== Waterways ===
+Egyptians used the now-disappeared branch of the Nile to transport the tons of construction materials. A 2012 study led by geographer Hader Sheisha at Aix-Marseille University proposed that the former waterscapes and higher river levels around 4,500 years ago facilitated the construction of the Giza Pyramid Complex. The Nile's present waterways have receded too far from the pyramid sites to be of use.
+A new study published in May 2024 mapped an extinct branch of the Nile, Ahramat Branch, which once flowed near Egypt's Great Pyramid and other Giza monuments. Using satellite imaging and sediment core analysis, researchers suggested that the 64 kilometres (40 mi) waterway was crucial for transporting materials and labor for pyramid construction. The branch, which was about 0.5 kilometres (0.31 mi) wide with a depth of at least 25 metres (82 ft), likely disappeared due to drought and desertification.
+It has been suggested that locks were used to elevate barges along waterways leading to pyramid construction sites, but there is a lack of evidence of any on-site use of hydraulic force.
+
+== Pyramid building experiments ==
+
+=== Yoshimura ===
+In 1978, Nippon TV funded the pyramid building project conceived by archaeologist Sajuki Yoshimura. It was originally planned as a 1 to 5 scale model of the Great Pyramid. Because of the limited budget, the size had to be drastically reduced when the price of limestone rose as the project gained publicity. A concrete foundation had to be poured as the selected site offered no bedrock basis. With the help of two cranes and a forklift, the pyramid was built to reach a height of 11 metres (36 ft), with a 15 metres (49 ft) base. The structure was ultimately dismantled and hauled away.
+
+=== Nova ===
+In 1992, Egyptologist Mark Lehner and stonemason Roger Hopkins conducted a three-week pyramid-building experiment for a Nova television episode. They built a pyramid 6 metres (20 ft) high by 9 metres (30 ft) wide, consisting of a total of 162 cubic metres (5,700 ft3), or about 405 tons. It was made out of 186 stones weighing an average of 2.2 tons each. Twelve quarrymen carved 186 stones in 22 days, and the structure was erected by 44 men. As a modern shortcut, they used iron hammers, chisels and levers (the ancient Egyptians were limited to using copper and later bronze and wood), but Lehner and Hopkins did experiments with copper tools, noting that they were adequate for the job in hand, if additional manpower was available to constantly resharpen them; they estimated they would have needed around 20 extra men for this maintenance. Another shortcut taken was the use of a front-end loader or fork lift truck, but modern machinery was not used to finish the construction. They used levers to lift the capstone to a height of 20 feet (6.1 m). Four or five men were able to use levers on stones less than one ton to flip them over and transport them by rolling, but larger stones had to be towed. Lehner and Hopkins found that by putting the stones on wooden sledges and sliding the sledges on wooden tracks, they were able to tow a two-ton stone with 12 to 20 men. The wood for these sledges and tracks would have to have been imported from Lebanon at great cost since there was little, if any, wood in ancient Egypt. While the builders failed to duplicate the precise jointing created by the ancient Egyptians, Hopkins was confident that this could have been achieved with more practice.
+
+== Great Pyramid ==
+
+Some research suggests other estimates to the accepted workforce size. For instance, physicist Kurt Mendelssohn calculated that the workforce may have been 50,000 men at most, while Ludwig Borchardt and Louis Croon placed the number at 36,000. According to Miroslav Verner, a workforce of no more than 30,000 was needed in the Great Pyramid's construction. Evidence suggests that around 5,000 were permanent workers on salaries with the balance working three- or four-month shifts in lieu of taxes while receiving subsistence "wages" of ten loaves of bread and a jug of beer per day. Zahi Hawass believes that the majority of workers may have been volunteers. Most archaeologists agree that only about 4,000 of the total workforce were labourers who quarried the stone, hauled blocks to the pyramid, and set the blocks in place. The vast majority of the workforce provided support services such as scribes, toolmakers, and other backup services. The tombs of supervisors contain inscriptions regarding the organisation of the workforce. There were two crews of approximately 2,000 workers sub-divided into named gangs of 1,000. The gangs were divided into five phyles of 200 which were in turn split into groups of around 20 workers grouped according to their skills, with each group having their own project leader and a specific task.
+A construction management study carried out by the firm Daniel, Mann, Johnson, & Mendenhall in association with Mark Lehner, and other Egyptologists, estimates that the total project required an average workforce of 14,567 people and a peak workforce of 40,000. Without the use of pulleys, wheels, or iron tools, they used critical path analysis to suggest the Great Pyramid was completed from start to finish in approximately 10 years. Their study estimates the number of blocks used in construction was between 2 and 2.8 million (an average of 2.4 million), but settles on a reduced finished total of 2 million after subtracting the estimated volume of the hollow spaces of the chambers and galleries. Most sources agree on this number of blocks somewhere above 2.3 million. Their calculations suggest the workforce could have sustained a rate of 180 blocks per hour (3 blocks/minute) with ten-hour workdays for putting each individual block in place. They derived these estimates from modern third-world construction projects that did not use modern machinery, but conclude it is still unknown exactly how the Great Pyramid was built. As Dr. Craig Smith of the team points out:

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+---
+title: "Construction of the Egyptian pyramids"
+chunk: 5/5
+source: "https://en.wikipedia.org/wiki/Construction_of_the_Egyptian_pyramids"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:22.840815+00:00"
+instance: "kb-cron"
+---
+
+The logistics of construction at the Giza site are staggering when you think that the ancient Egyptians had no pulleys, no wheels, and no iron tools. Yet, the dimensions of the pyramid are extremely accurate and the site was leveled within a fraction of an inch over the entire 13.1-acre base. This is comparable to the accuracy possible with modern construction methods and laser leveling. That's astounding. With their 'rudimentary tools', the pyramid builders of ancient Egypt were about as accurate as we are today with 20th-century technology.
+
+The entire Giza Plateau is believed to have been constructed over the reign of five pharaohs in less than a hundred years, which generally includes: the Great Pyramid, Khafre and Menkaure's pyramids, the Great Sphinx, the Sphinx, and Valley Temples, 35 boat pits cut out of solid bedrock, and several causeways, as well as paving nearly the entire plateau with large stones. This does not include Khafre's brother Djedefre's northern pyramid at Abu Rawash, which would have also been built during this time frame of 100 years. In the hundred years prior to Giza—beginning with Djoser, who ruled from 2687 to 2667 BC, and amongst dozens of other temples, smaller pyramids, and general construction projects—four other massive pyramids were built: the Step pyramid of Saqqara (believed to be the first Egyptian pyramid), the pyramid of Meidum, the Bent Pyramid, and the Red Pyramid. Also during this period (between 2686 and 2498 BC) the Sadd el-Kafara dam, which used an estimated 100,000 cubic meters of rock and rubble, was built.
+In October 2018, a team of archaeologists from the Institut Français d'Archéologie Orientale and University of Liverpool announced the discovery of the remains of a 4,500-year-old ramp contraption at Hatnub, excavated since 2012. This method, which aided in lifting the heavy alabaster stones up from their quarries, may have been used to build Egypt's Great Pyramid as well. Yannis Gourdon, co-director of the joint mission at Hatnub, said:
+
+This system is composed of a central ramp flanked by two staircases with numerous post holes, using a sled which carried a stone block and was attached with ropes to these wooden posts, ancient Egyptians were able to pull up the alabaster blocks out of the quarry on very steep slopes of 20 percent or more ... As this system dates back at least to Khufu's reign, that means that during the time of Khufu, ancient Egyptians knew how to move huge blocks of stone using very steep slopes. Therefore, they could have used it for the construction [of] his pyramid.
+
+=== Internal ramp hypothesis ===
+
+Houdin's father was an architect who, in 1999, thought of a construction method that, it seemed to him, made more sense than any existing method proposed for building pyramids. To develop this hypothesis, Jean-Pierre Houdin, also an architect, gave up his job and set about drawing the first fully functional CAD architectural model of the Great Pyramid of Giza.
+
+His scheme involves using a regular external ramp to build the first 30% of the pyramid, with an "internal ramp" taking stones up beyond that height. The stones of the external ramp are re-cycled into the upper stories, thus explaining the otherwise puzzling lack of evidence for ramps.
+After four years working alone, Houdin was joined by a team of engineers from the French 3D software company Dassault Systèmes, who used the most modern computer-aided design technology available to further refine and test the hypothesis, making it (according to Houdin) the only one proven to be a viable technique. Houdin published his theory in the books Khufu: The Secrets Behind the Building of the Great Pyramid in 2006 and The Secret of the Great Pyramid, co-written in 2008 with Egyptologist Bob Brier.
+In Houdin's method, each ramp inside the pyramid ended at an open space, a notch temporarily left open in the edge of the construction. This 10-square-meter clear space housed a crane that lifted and rotated each 2.5-ton block, to ready it for eight men to drag up the next internal ramp. There is a notch of sorts in one of the right places, and in 2008 Houdin's co-author Bob Brier, with a National Geographic film crew, entered a previously unremarked chamber that could be the start of one of these internal ramps. In 1986 a member of the French team (see below) saw a desert fox at this notch, rather as if it had ascended internally.
+Houdin's thesis remains unproven and in 2007, Egyptologist David Jeffreys from the University College London described the internal spiral hypothesis as "far-fetched and horribly complicated", while Oxford University's John Baines, declared he was "suspicious of any theory that seeks to explain only how the Great Pyramid was built".
+Houdin has another hypothesis developed from his architectural model, one that could finally explain the internal "Grand Gallery" chamber that otherwise appears to have little purpose. He believes the gallery acted as a trolley chute/guide for counterbalance weights. It enabled the raising of the five 60-ton granite beams that roof the King's Chamber. Houdin and Brier and the Dassault team are already credited with proving for the first time that cracks in beams appeared during construction, were examined and tested at the time and declared relatively harmless.
+
+== See also ==
+Ancient Egyptian technology
+List of megalithic sites
+Seven wonders of the world
+
+== References ==
+
+== External links ==
+How to Build a Pyramid, Archaeology Magazine, May/June 2007 Archived 21 February 2010 at the Wayback Machine
+Engineering the Pyramids - Materials Science and Engineering @ Drexel University
+Rope pull hypothesis - alternative hypothesis by Heribert Illig and Franz Löhner
+Collection of alternative construction essays
+Did the Great Pyramid Have an Elevator? The Structural Engineer, April 2009
+The main problems / drawbacks of all ramp systems
+3D Unveils Great Pyramid's Mystery - illustrates hypothesis of Houdin and Brier.
+Did the Egyptians create a canal and a port to bring stone to the Great Pyramid?
+A Device for Lifting Pyramid Stones

data/en.wikipedia.org/wiki/Constructive_heuristic-0.md

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+---
+title: "Constructive heuristic"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Constructive_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:26.519422+00:00"
+instance: "kb-cron"
+---
+
+A constructive heuristic is a type of heuristic method which starts with an empty solution and repeatedly extends the current solution until a complete solution is obtained. It differs from local search heuristics which start with a complete solution and then try to improve the current solution further via local moves. Examples of some famous problems that are solved using constructive heuristics are the flow shop scheduling,  the vehicle routing problem and the open shop problem.
+
+
+== See also ==
+Evolutionary algorithms
+Genetic algorithms
+Local search (optimization)
+Metaheuristics
+
+
+== References ==

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+---
+title: "Contagion heuristic"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Contagion_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:27.704654+00:00"
+instance: "kb-cron"
+---
+
+The contagion heuristic is a psychological heuristic which follows the law of contagion and the law of similarity, leading people to avoid contact with people or objects viewed as "contaminated" by previous contact with someone or something viewed as bad—or, less often, to seek contact with objects that have been in contact with people or things considered good. For example, people tend to view food that has touched the ground as contaminated by the ground, and therefore unfit to eat, or view a person who has touched a diseased person as likely to carry the disease (regardless of the actual contagiousness of the disease).
+The contagion heuristic can include "magical thinking", in which well-educated adults will think that touching an object transfers their qualities ("essence") to it: for example, a sweater worn by Adolf Hitler is thought to bear his negative essence and to be capable of transmitting it to another wearer. The perception of essence-transfer extends to rituals to purify items viewed as spiritually contaminated, such as having Mother Teresa wear Hitler's sweater to counteract his essence.
+
+== Types ==
+The contagion heuristic can be separated into three categories:
+
+=== 1. Positive or negative ===
+Contagion can be negative or positive depending on how the contaminating object or person is perceived.
+Negative contagion occurs when a seemingly negative object comes into contact with another object. For example, a brief contact of food with an object seen as disgusting will render the object "contaminated" regardless of the actual implications to the object such as the transfer of viruses. Hence this might lead to an irrational rejection of the food.
+Positive contagion occurs when a seemingly positive object comes into contact with another object.
+In both these examples, contact is required as in the law of contagion however, this can also be applied to an object associated with another. For example, reluctance to come in contact with a plastic replica of an object perceived as disgusting (negative) even though there are no negative implications from touching it.
+
+=== 2. Forwards or backwards ===
+The forwards contagion heuristic occurs when an object has been in contact with someone or something else seen as positively or negatively contaminated. For example, forward contagion occurs when someone is now in contact with, or about to consume, a piece of food that has touched the ground.
+The backwards contagion heuristic occurs with objects that come into contact with something or someone else seen as positively or negatively contaminated. For example,  the unwillingness to allow one's personal objects to come into possession of people who are disliked. Findings from Kramer and Block show that consumers may be less willing to accept a high auction price for a teddy bear they were selling if the person buying was perceived to be of low moral quality (such as a sex offender) as opposed to high moral quality (e.g. a mother of a young child)
+For the backward contagion to be more effective the person should have owned it rather than mere contact.
+
+=== 3. Physical or non-physical ===
+There is a range of ways an item or person can become contaminated. These were grouped after testing the 'predicted purification potency' which is the level at which the object can be 'de-contaminated' by an action: e.g. washing.
+
+==== Physical sources ====
+Physical Germ Model  Carried by a living invisible entity.(e.g. Salmonella)
+Physical Residue Model  (e.g. Dandruff, Sweat)
+Associative Model  How much an object reminds the person of something or someone
+In the cases of 1 and 2, the predicted purity potency turned out to be highly similar. In both cases, they are effectively moderated by washing, especially in the case of source 2.
+For the associative model, a change in the appearance of the object seemed to be highly effective. In this case, physical contact is not required (but is seen as more contaminated if it occurs) for the object to be seen as contaminated and hence differs from the above two cases. However, it is distinguishable from non-physical models as there is no spiritual element.
+
+==== Non-physical sources ====
+Symbolic Interaction Model Interaction with something of symbolic importance (e.g. sacramental bread which for certain individuals is simply the combination of wheat flour, yeast, water and salt without its contact with a holy person like a priest)
+Spiritual Essence Model When the 'essence' of a person is transferred to an object or person by contact. (e.g., a jumper owned by Hitler is seen as negatively contaminated as his 'essence' has transferred and he is generally perceived as of low moral quality)
+These non-physical sources of contagion are more difficult to erase than the above three physical sources however, they both tend to be effectively reduced by opposite valence contact; that is, an opposite but equal force. For example, to reduce the negative contaminants on Hitler's jumper, someone of high moral quality will be needed to counteract the 'essence'.
+
+== Discovery ==
+Anthropologists suggested a contagion heuristic or more specifically magic thinking when traditional societies were observed doing cultural practices such as transferring a person's identity (or soul) to inanimate objects such as fingernails and hair which were seen as highly "contagious". Furthermore, these beliefs continued to also include objects that had been in physical contact with the person.
+Whilst initially thought to only apply to traditional societies, further research by Rozin and Nemeroff showed that it could also be applied to Western societies. Observing that the contagion heuristic seems to only apply to humans, they created three routes of reasoning.

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+---
+title: "Contagion heuristic"
+chunk: 2/2
+source: "https://en.wikipedia.org/wiki/Contagion_heuristic"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:27.704654+00:00"
+instance: "kb-cron"
+---
+
+A rejection of potentially offensive food: People are unlikely to touch foods that elicit disgust in attempts to protect our health (e.g. disgust towards uncooked chicken as it is seen as contaminated with potential harmful microorganisms like salmonella).
+Illness transfer between humans: Avoid touching a 'contaminated' ill person due to fear of getting ill.
+Support Relationships: Positive contagion encourages highly intimate acts with people perceived as positively contaminated such as family and lovers. (sexual intimacy which would otherwise elicit disgust without love and lust)
+Hence, the contagion heuristic seems to be a pre-adaptation, that is it evolved to be beneficial to health and relationships, supporting the survival of our species, but now no longer serves a person in the current environment.
+
+== Critiques ==
+Positive contagion is relatively weak and might just be an over-extension of the negative contagion principle. This is most likely due to the negative bias: that is, when given two cases, one of negative and one of positive of equal force, the negative case will have a greater impact. As an old Russian phrase states, "A spoonful of tar can spoil a barrel of honey, but a spoonful of honey does nothing for a barrel of tar.″
+The associative model doesn't require any physical contact as stated as necessary in the Laws of Contagion, therefore can be seen as an alternative to contagion rather than part of it. For example, we are more inclined to consume food when the word 'natural' is involved regardless of the actual content; the positive contaminant of the word 'natural' is enough to alter decisions due to our associations with the word.
+Inattention: People tend not to think about the interpersonal history of entities that are seen as contaminated. When they receive change in a shop, they do not think of the long string of humans, who handled it previously.
+
+== Variation ==
+
+=== Age ===
+As the contagion heuristic stems from understanding that harmful microbes can exist in certain foods, this limits the extent to which children apply this heuristic. This is because the knowledge and understanding of invisible sources of contamination such as germs and how they spread or multiply are not understandable to young children. Studies have shown that at the age of 3-5, children begin to develop contagion sensitivity (degree to which someone knows if something is contaminated or not). Whilst they begin to acknowledge entities as negatively contaminated, they do not understand the biological reasoning until an older age.
+
+=== Culture and religion ===
+Cultural variation plays a large role in disgust as it affects what is seen as positive or negative and hence certain societies may react to different contaminants. For example, cultural traditions such as removing shoes upon entering a house is practiced by many Asian societies (due to negative contamination) however not by American societies.
+A study by Rozin and Nemeroff shows that religious groups have their own rules on what is seen as contaminated. The experiment explored whether Jews following the Laws of Kashrut would consume kosher foods that had been in contact or association with non-kosher entities. The report showed that even when the food is only contaminated by similarity (e.g. vegetarian bacon), most would deter from consumption. However, these problems can be controlled by creating rituals to decontaminate the food or setting limits on how contamination. In Judaism, the boundary of allowing non-kosher entities contaminate kosher food is 1/60th of the total volume of the contaminated good given the contamination occurs by accident.
+
+== See also ==
+Projective identification
+Sacred contagion
+Sympathetic magic
+Social intuitionism
+
+== References ==
+
+== Further reading ==
+Nemeroff, C., & Rozin, P.  (2000).  "The makings of the magical mind: The nature and function of sympathetic magical thinking."  In K. S. Rosengren, C. N. Johnson, & P. L. Harris (Eds.), Imagining the impossible: Magical, scientific, and religious thinking in children (pp. 1–34).  New York: Cambridge University Press. DOI 10.1017/CBO9780511571381.002
+Argo, Jennifer J.; Dahl, Darren W.; Morales, Andrea C. (December 2008). "Positive Consumer Contagion: Responses to Attractive Others in a Retail Context". Journal of Marketing Research. 45 (6): 690–701. doi:10.1509/jmkr.45.6.690. ISSN 0022-2437. S2CID 144293105.
+Rozin, Paul; Millman, Linda; Nemeroff, Carol (1986). "Operation of the laws of sympathetic magic in disgust and other domains". Journal of Personality and Social Psychology. 50 (4): 703–712. doi:10.1037/0022-3514.50.4.703. ISSN 1939-1315.
+Argo, Jennifer J.; Dahl, Darren W.; Morales, Andrea C. (April 2006). "Consumer Contamination: How Consumers React to Products Touched by Others". Journal of Marketing. 70 (2): 81–94. doi:10.1509/jmkg.70.2.081. ISSN 0022-2429. S2CID 167866086.
+Kramer, Thomas; Block, Lauren G. (July 2014). "Like Mike: Ability contagion through touched objects increases confidence and improves performance". Organizational Behavior and Human Decision Processes. 124 (2): 215–228. doi:10.1016/j.obhdp.2014.03.009.
+Savani, Krishna; Kumar, Satishchandra; Naidu, N. V. R.; Dweck, Carol S. (2011). "Beliefs about emotional residue: The idea that emotions leave a trace in the physical environment". Journal of Personality and Social Psychology. 101 (4): 684–701. doi:10.1037/a0024102. ISSN 1939-1315. PMID 21688925.
+Bower, Lennea. Sympathetic Magical Thinking in Decision Making: Differences for Animate and Inanimate Decision Targets (2014): ProQuest Dissertations and Theses.
+Paul Rozin, Sharon Wolf; Attachment to land: The case of the land of Israel for American and Israeli Jews and the role of contagion, Judgment and Decision Making, Vol. 3, No. 4, April 2008, pp. 325–33
+Kelly, D. (2013). ‘Moral Disgust and The Tribal Instincts Hypothesis,' Cooperation and Its Evolution, Eds. K. Sterelny, R. Joyce, Calcott, B, & B. Fraser. Cambridge, MA: The MIT Press, pages 503-524
+Hejmadi, Ahalya; Rozin, Paul; Siegal, Michael (2004). "Once in Contact, Always in Contact: Contagious Essence and Conceptions of Purification in American and Hindu Indian Children". Developmental Psychology. 40 (4): 467–476. doi:10.1037/0012-1649.40.4.467. ISSN 1939-0599. PMID 15238036.

data/en.wikipedia.org/wiki/Content_sniffing-0.md

@@ -0,0 +1,35 @@
+---
+title: "Content sniffing"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Content_sniffing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:57:28.890773+00:00"
+instance: "kb-cron"
+---
+
+Content sniffing, also known as media type sniffing or MIME sniffing, is the practice of inspecting the content of a byte stream to attempt to deduce the file format of the data within it. Content sniffing is generally used to compensate for a lack of accurate metadata that would otherwise be required to enable the file to be interpreted correctly. Content sniffing techniques tend to use a mixture of techniques that rely on the redundancy found in most file formats: looking for file signatures and magic numbers, and heuristics including searching for well-known representative substrings, the use of byte frequency and n-gram tables, and Bayesian inference.
+Multipurpose Internet Mail Extensions (MIME) sniffing was, and still is, used by some web browsers, including notably Microsoft's Internet Explorer, in an attempt to help web sites which do not correctly signal the MIME type of web content display. However, doing this opens up a serious security vulnerability, in which, by confusing the MIME sniffing algorithm, the browser can be manipulated into interpreting data in a way that allows an attacker to carry out operations that are not expected by either the site operator or user, such as cross-site scripting. Moreover, by making sites which do not correctly assign MIME types to content appear to work correctly in those browsers, it fails to encourage the correct labeling of material, which in turn makes content sniffing necessary for these sites to work, creating a vicious circle of incompatibility with web standards and security best practices.
+A specification exists for media type sniffing in HTML5, which attempts to balance the requirements of security with the need for reverse compatibility with web content with missing or incorrect MIME-type data. It attempts to provide a precise specification that can be used across implementations to implement a single well-defined and deterministic set of behaviors.
+The UNIX file command can be viewed as a content sniffing application.
+
+
+== Charset sniffing ==
+
+Numerous web browsers use a more limited form of content sniffing to attempt to determine the character encoding of text files for which the MIME type is already known. This technique is known as charset sniffing or codepage sniffing and, for certain encodings, may be used to bypass security restrictions too. For instance, Internet Explorer 7 may be tricked to run JScript in circumvention of its policy by allowing the browser to guess that an HTML-file was encoded in UTF-7. This bug is worsened by the feature of the UTF-7 encoding which permits multiple encodings of the same text and, specifically, alternative representations of ASCII characters.
+Most encodings do not allow evasive presentations of ASCII characters, so charset sniffing is less dangerous in general because, due to the historical accident of the ASCII-centric nature of scripting and markup languages, characters outside the ASCII repertoire are more difficult to use to circumvent security boundaries, and misinterpretations of character sets tend to produce results no worse than the display of mojibake.
+
+
+== See also ==
+Browser sniffing
+
+
+== References ==
+
+
+== External links ==
+X-Content-Type-Options header
+MIME Sniffing Standard
+L. Masinter (March 27, 2011). "Internet Media Types and the Web". IETF. Retrieved 2012-07-14.
+A. Barth, I. Hickson (January 24, 2011). "Media Type Sniffing". IETF. Retrieved 2012-07-14.
+David Risney. "Mime-sniffing". Retrieved 2012-07-14.

data/en.wikipedia.org/wiki/Continuum_hypothesis-0.md

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+---
+title: "Continuum hypothesis"
+chunk: 1/5
+source: "https://en.wikipedia.org/wiki/Continuum_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:15.765779+00:00"
+instance: "kb-cron"
+---
+
+In mathematics, specifically set theory, the continuum hypothesis (abbreviated CH) is a hypothesis about the possible sizes of infinite sets. It states:
+
+There is no set whose cardinality is strictly between that of the integers and the real numbers. The name of the hypothesis comes from the term continuum for the real numbers. In Zermelo–Fraenkel set theory with the axiom of choice (ZFC), this is equivalent to the following equation in aleph numbers: 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            1
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}=\aleph _{1}}
+  
+, or even shorter with beth numbers: 
+  
+    
+      
+        
+          ℶ
+          
+            1
+          
+        
+        =
+        
+          ℵ
+          
+            1
+          
+        
+      
+    
+    {\displaystyle \beth _{1}=\aleph _{1}}
+  
+.
+The continuum hypothesis was advanced by Georg Cantor in 1878. It became one of the most studied problems in set theory, and establishing its truth or falsehood was the first of Hilbert's 23 problems presented in 1900. The answer to this problem is independent of ZFC. This means the axioms of ZFC can neither prove nor disprove the continuum hypothesis, meaning either the continuum hypothesis or its negation can be added as an axiom to ZFC set theory, with the resulting theory being consistent if and only if ZFC is consistent. This independence was proved in 1963 by Paul Cohen, complementing earlier work by Kurt Gödel in 1940.
+The generalized continuum hypothesis states that 
+  
+    
+      
+        
+          ℵ
+          
+            α
+            +
+            1
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha +1}=2^{\aleph _{\alpha }}}
+  
+ for every ordinal 
+  
+    
+      
+        α
+      
+    
+    {\displaystyle \alpha }
+  
+.
+
+== History ==
+The continuum hypothesis was first introduced by Georg Cantor in his 1878 paper "Ein Beitrag zur Mannigfaltigkeitslehre", in a form now called the weak continuum hypothesis which is equivalent to the standard formulation under the then-undeveloped axiom of choice. Cantor initially presented the weak continuum hypothesis as a theorem, but did not give a proof and later became uncertain of it. On 25 October 1882, Cantor wrote to his correspondent Gösta Mittag-Leffler, and formulated the continuum hypothesis (CH) in its modern form and gave his belief he could prove it. By the 1890s, many mathematicians in Germany and France were aware of the problem. Cantor tried for many years to prove CH but never succeeded.
+It became the first on David Hilbert's list of important open questions that was presented at the International Congress of Mathematicians (ICM) in the year 1900 in Paris. At that point, axiomatic set theory was not yet formulated.
+Many erroneous proofs and disproofs of CH were given. As early as 1884, Paul Tannery claimed to prove CH, but the proof was erroneous. In 1890, Beppo Levi claimed to have a proof from assuming that every subset of the real numbers has the Baire property, but no proof was ever published. At the 1904 ICM in Heidelberg, Gyula Kőnig announced he had disproven CH, drawing wide attention that even reached the Grand Duke of Baden Frederick I via Felix Klein, but a flaw in the proof was found the next day. Felix Bernstein also published an attempted proof of CH in 1904, but it was wrong and attracted little response. In 1926, Hilbert claimed to have solved the continuum hypothesis and gave a proof sketch, but this was also incorrect, although it influenced later ideas in recursion theory.
+In 1906, Kőnig revised part of his attempted CH disproof and established Kőnig's theorem, which by using the concept of cofinality introduced in 1908 by Felix Hausdorff, shows that result that 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}}
+  
+ cannot equal 
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }}
+  
+ for 
+  
+    
+      
+        α
+      
+    
+    {\displaystyle \alpha }
+  
+ with cofinality 
+  
+    
+      
+        ω
+      
+    
+    {\displaystyle \omega }
+  
+. For example, 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+        ≠
+        
+          ℵ
+          
+            ω
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}\neq \aleph _{\omega }}
+  
+. Hausdorff formulated the question of whether 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            α
+          
+        
+        +
+        1
+      
+    
+    {\displaystyle 2^{\aleph _{\alpha }}=\aleph _{\alpha }+1}
+  
+ for all ordinals 
+  
+    
+      
+        α
+      
+    
+    {\displaystyle \alpha }
+  
+, which would be named the generalized continuum hypothesis by Alfred Tarski in 1925. In 1923, Thoralf Skolem conjectured that CH could not be settled by the axioms of Zermelo set theory.
+Kurt Gödel proved in 1940 that the negation of the continuum hypothesis, i.e., the existence of a set with intermediate cardinality, could not be proved in standard set theory. The second half of the independence of the continuum hypothesis – i.e., unprovability of the nonexistence of an intermediate-sized set – was proved in 1963 by Paul Cohen.
+
+== Cardinality of infinite sets ==

data/en.wikipedia.org/wiki/Continuum_hypothesis-1.md

@@ -0,0 +1,239 @@
+---
+title: "Continuum hypothesis"
+chunk: 2/5
+source: "https://en.wikipedia.org/wiki/Continuum_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:15.765779+00:00"
+instance: "kb-cron"
+---
+
+Two sets are said to have the same cardinality or cardinal number if there exists a bijection (a one-to-one correspondence) between them. Intuitively, for two sets 
+  
+    
+      
+        S
+      
+    
+    {\displaystyle S}
+  
+ and 
+  
+    
+      
+        T
+      
+    
+    {\displaystyle T}
+  
+ to have the same cardinality means that it is possible to "pair off" elements of 
+  
+    
+      
+        S
+      
+    
+    {\displaystyle S}
+  
+ with elements of 
+  
+    
+      
+        T
+      
+    
+    {\displaystyle T}
+  
+ in such a fashion that every element of 
+  
+    
+      
+        S
+      
+    
+    {\displaystyle S}
+  
+ is paired off with exactly one element of 
+  
+    
+      
+        T
+      
+    
+    {\displaystyle T}
+  
+ and vice versa. Hence, the set 
+  
+    
+      
+        {
+        
+          banana
+        
+        ,
+        
+          apple
+        
+        ,
+        
+          pear
+        
+        }
+      
+    
+    {\displaystyle \{{\text{banana}},{\text{apple}},{\text{pear}}\}}
+  
+ has the same cardinality as 
+  
+    
+      
+        {
+        
+          yellow
+        
+        ,
+        
+          red
+        
+        ,
+        
+          green
+        
+        }
+      
+    
+    {\displaystyle \{{\text{yellow}},{\text{red}},{\text{green}}\}}
+  
+ despite the sets themselves containing different elements.
+With infinite sets such as the set of integers or rational numbers, the existence of a bijection between two sets becomes more difficult to demonstrate. The rational numbers 
+  
+    
+      
+        
+          Q
+        
+      
+    
+    {\displaystyle \mathbb {Q} }
+  
+ seemingly form a counterexample to the continuum hypothesis: the integers form a proper subset of the rationals, which themselves form a proper subset of the reals, so intuitively, there are more rational numbers than integers and more real numbers than rational numbers. However, this intuitive analysis is flawed since it does not take into account the fact that all three sets are infinite. Perhaps more importantly, it in fact conflates the concept of "size" of the set 
+  
+    
+      
+        
+          Q
+        
+      
+    
+    {\displaystyle \mathbb {Q} }
+  
+ with the order or topological structure placed on it. In fact, it turns out the rational numbers can actually be placed in one-to-one correspondence with the integers, and therefore the set of rational numbers is the same size (cardinality) as the set of integers: they are both countable sets.
+Cantor gave two proofs that the cardinality of the set of integers is strictly smaller than that of the set of real numbers (see Cantor's first uncountability proof and Cantor's diagonal argument). His proofs, however, give no indication of the extent to which the cardinality of the integers is less than that of the real numbers. Cantor proposed the continuum hypothesis as a possible solution to this question.
+In simple terms, the Continuum Hypothesis (CH) states that the set of real numbers has minimal possible cardinality which is greater than the cardinality of the set of integers. That is, every infinite set 
+  
+    
+      
+        S
+        ⊆
+        
+          R
+        
+      
+    
+    {\displaystyle S\subseteq \mathbb {R} }
+  
+ of real numbers can either be mapped one-to-one into the integers or the real numbers can be mapped one-to-one into 
+  
+    
+      
+        S
+      
+    
+    {\displaystyle S}
+  
+. Since the real numbers are equinumerous with the powerset of the integers, i.e. 
+  
+    
+      
+        
+          |
+        
+        
+          R
+        
+        
+          |
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle |\mathbb {R} |=2^{\aleph _{0}}}
+  
+, CH can be restated as follows:
+
+Assuming the axiom of choice, there is a unique smallest cardinal number 
+  
+    
+      
+        
+          ℵ
+          
+            1
+          
+        
+      
+    
+    {\displaystyle \aleph _{1}}
+  
+ greater than 
+  
+    
+      
+        
+          ℵ
+          
+            0
+          
+        
+      
+    
+    {\displaystyle \aleph _{0}}
+  
+, and the continuum hypothesis is in turn equivalent to the equality 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            1
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}=\aleph _{1}}
+  
+.

data/en.wikipedia.org/wiki/Continuum_hypothesis-2.md

@@ -0,0 +1,146 @@
+---
+title: "Continuum hypothesis"
+chunk: 3/5
+source: "https://en.wikipedia.org/wiki/Continuum_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:15.765779+00:00"
+instance: "kb-cron"
+---
+
+== Independence from ZFC ==
+The independence of the continuum hypothesis (CH) from Zermelo–Fraenkel set theory (ZF) follows from combined work of Kurt Gödel  and Paul Cohen.
+Gödel
+showed that CH cannot be disproved from ZF, even if the axiom of choice (AC) is adopted, i.e. from ZFC. Gödel's proof shows that both CH and AC hold in the constructible universe 
+  
+    
+      
+        L
+      
+    
+    {\displaystyle L}
+  
+, an inner model of ZF set theory, assuming only the axioms of ZF.  The existence of an inner model of ZF in which additional axioms hold shows that the additional axioms are (relatively) consistent with ZF, provided ZF itself is consistent. The latter condition cannot be proved in ZF itself, due to Gödel's incompleteness theorems, but is widely believed to be true and can be proved in stronger set theories.
+Cohen showed that CH cannot be proven from the ZFC axioms, completing the overall independence proof. To prove his result, Cohen developed the method of forcing, which has become a standard tool in set theory. Essentially, this method begins with a model of ZF in which CH holds and constructs another model which contains more sets than the original in a way that CH does not hold in the new model. Cohen was awarded the Fields Medal in 1966 for his proof.
+Cohen's independence proof shows that CH is independent of ZFC. Further research has shown that CH is independent of all known large cardinal axioms in the context of ZFC. Moreover, it has been shown that the cardinality of the continuum 
+  
+    
+      
+        
+          
+            c
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle {\mathfrak {c}}=2^{\aleph _{0}}}
+  
+ can be any cardinal consistent with Kőnig's theorem. A result of Solovay, proved shortly after Cohen's result on the independence of the continuum hypothesis, shows that in any model of ZFC, if 
+  
+    
+      
+        κ
+      
+    
+    {\displaystyle \kappa }
+  
+ is a cardinal of uncountable cofinality, then there is a forcing extension in which 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+        =
+        κ
+      
+    
+    {\displaystyle 2^{\aleph _{0}}=\kappa }
+  
+. However, per Kőnig's theorem, it is not consistent to assume 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}}
+  
+ is 
+  
+    
+      
+        
+          ℵ
+          
+            ω
+          
+        
+      
+    
+    {\displaystyle \aleph _{\omega }}
+  
+ or 
+  
+    
+      
+        
+          ℵ
+          
+            
+              ω
+              
+                1
+              
+            
+            +
+            ω
+          
+        
+      
+    
+    {\displaystyle \aleph _{\omega _{1}+\omega }}
+  
+ or any cardinal with cofinality 
+  
+    
+      
+        ω
+      
+    
+    {\displaystyle \omega }
+  
+.
+The continuum hypothesis is closely related to many statements in analysis, point-set topology and measure theory. As a result of its independence, many substantial conjectures in those fields have subsequently been shown to be independent as well.
+The independence from ZFC means that proving or disproving the CH within ZFC is impossible.  However, Gödel and Cohen's negative results are not universally accepted as disposing of all interest in the continuum hypothesis. The continuum hypothesis remains an active topic of research: see Woodin and Koellner for an overview of the current research status.
+The continuum hypothesis and the axiom of choice were among the first genuinely mathematical statements shown to be independent of ZF set theory. Although the existence of some statements independent of ZFC had already been known more than two decades prior: for example, assuming good soundness properties and the consistency of ZFC, Gödel's incompleteness theorems published in 1931 establish that there is a formal statement Con(ZFC) (one for each appropriate Gödel numbering scheme) expressing the consistency of ZFC, that is also independent of it. The latter independence result indeed holds for many theories.

data/en.wikipedia.org/wiki/Continuum_hypothesis-3.md

@@ -0,0 +1,145 @@
+---
+title: "Continuum hypothesis"
+chunk: 4/5
+source: "https://en.wikipedia.org/wiki/Continuum_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:15.765779+00:00"
+instance: "kb-cron"
+---
+
+== Arguments for and against the continuum hypothesis ==
+Gödel believed that CH is false, and that his proof that CH is consistent with ZFC only shows that the Zermelo–Fraenkel axioms do not adequately characterize the universe of sets.  Gödel was a Platonist  and therefore had no problems with asserting the truth and falsehood of statements independent of their provability. Cohen, though a formalist, also tended towards rejecting CH.
+Historically, mathematicians who favored a "rich" and "large" universe of sets were against CH, while those favoring a "neat" and "controllable" universe favored CH. Parallel arguments were made for and against the axiom of constructibility, which implies CH. More recently, Matthew Foreman has pointed out that ontological maximalism can actually be used to argue in favor of CH, because among models that have the same reals, models with "more" sets of reals have a better chance of satisfying CH.
+Another viewpoint is that the conception of set is not specific enough to determine whether CH is true or false. This viewpoint was advanced as early as 1923 by Skolem, even before Gödel's first incompleteness theorem. Skolem argued on the basis of what is now known as Skolem's paradox, and it was later supported by the independence of CH from the axioms of ZFC since these axioms are enough to establish the elementary properties of sets and cardinalities. In order to argue against this viewpoint, it would be sufficient to demonstrate new axioms that are supported by intuition and resolve CH in one direction or another. Although the axiom of constructibility does resolve CH, it is not generally considered to be intuitively true any more than CH is generally considered to be false.
+At least two other axioms have been proposed that have implications for the continuum hypothesis, although these axioms have not currently found wide acceptance in the mathematical community. In 1986, Chris Freiling presented an argument against CH by showing that the negation of CH is equivalent to Freiling's axiom of symmetry, a statement derived by arguing from particular intuitions about probabilities. Freiling believes this axiom is "intuitively clear" but others have disagreed.
+A difficult argument against CH developed by W. Hugh Woodin has attracted considerable attention since the year 2000. Foreman does not reject Woodin's argument outright but urges caution. Woodin proposed a new hypothesis that he labeled the "(*)-axiom", or "Star axiom". The Star axiom would imply that 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}}}
+  
+ is 
+  
+    
+      
+        
+          ℵ
+          
+            2
+          
+        
+      
+    
+    {\displaystyle \aleph _{2}}
+  
+, thus falsifying CH. The Star axiom was bolstered by an independent May 2021 proof showing the Star axiom can be derived from a variation of Martin's maximum. However, Woodin stated in the 2010s that he now instead believes CH to be true, based on his belief in his new "ultimate L" conjecture.
+Solomon Feferman argued that CH is not a definite mathematical problem.  He proposed a theory of "definiteness" using a semi-intuitionistic subsystem of ZF that accepts classical logic for bounded quantifiers but uses intuitionistic logic for unbounded ones, and suggested that a proposition 
+  
+    
+      
+        ϕ
+      
+    
+    {\displaystyle \phi }
+  
+ is mathematically "definite" if the semi-intuitionistic theory can prove 
+  
+    
+      
+        (
+        ϕ
+        ∨
+        ¬
+        ϕ
+        )
+      
+    
+    {\displaystyle (\phi \lor \neg \phi )}
+  
+.  He conjectured that CH is not definite according to this notion, and proposed that CH should, therefore, be considered not to have a truth value. Peter Koellner wrote a critical commentary on Feferman's article.
+Joel David Hamkins proposes a multiverse approach to set theory and argues that "the continuum hypothesis is settled on the multiverse view by our extensive knowledge about how it behaves in the multiverse, and, as a result, it can no longer be settled in the manner formerly hoped for". In a related vein, Saharon Shelah wrote that he does "not agree with the pure Platonic view that the interesting problems in set theory can be decided, that we just have to discover the additional axiom. My mental picture is that we have many possible set theories, all conforming to ZFC".
+
+== Generalized continuum hypothesis ==
+The generalized continuum hypothesis (GCH) states that if an infinite set's cardinality lies between that of an infinite set S and that of the power set 
+  
+    
+      
+        
+          
+            P
+          
+        
+        (
+        S
+        )
+      
+    
+    {\displaystyle {\mathcal {P}}(S)}
+  
+ of S, then it has the same cardinality as either S or 
+  
+    
+      
+        
+          
+            P
+          
+        
+        (
+        S
+        )
+      
+    
+    {\displaystyle {\mathcal {P}}(S)}
+  
+. That is, for any infinite cardinal 
+  
+    
+      
+        λ
+      
+    
+    {\displaystyle \lambda }
+  
+ there is no cardinal 
+  
+    
+      
+        κ
+      
+    
+    {\displaystyle \kappa }
+  
+ such that 
+  
+    
+      
+        λ
+        <
+        κ
+        <
+        
+          2
+          
+            λ
+          
+        
+      
+    
+    {\displaystyle \lambda <\kappa <2^{\lambda }}
+  
+. GCH is equivalent to:

data/en.wikipedia.org/wiki/Continuum_hypothesis-4.md

@@ -0,0 +1,796 @@
+---
+title: "Continuum hypothesis"
+chunk: 5/5
+source: "https://en.wikipedia.org/wiki/Continuum_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:15.765779+00:00"
+instance: "kb-cron"
+---
+
+(occasionally called Cantor's aleph hypothesis).
+The beth numbers provide an alternative notation for this condition: 
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+        
+        =
+        
+          ℶ
+          
+            α
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }=\beth _{\alpha }}
+  
+ for every ordinal 
+  
+    
+      
+        α
+      
+    
+    {\displaystyle \alpha }
+  
+. The continuum hypothesis is the special case for the ordinal 
+  
+    
+      
+        α
+        =
+        1
+      
+    
+    {\displaystyle \alpha =1}
+  
+. GCH was first suggested by Philip Jourdain. For the early history of GCH, see Moore.
+Like CH, GCH is also independent of ZFC, but Sierpiński proved that ZF + GCH implies the axiom of choice (AC) (and therefore the negation of the axiom of determinacy, AD), so choice and GCH are not independent in ZF; there are no models of ZF in which GCH holds and AC fails. To prove this, Sierpiński showed GCH implies that every cardinality n is smaller than some aleph number, and thus can be ordered. This is done by showing that n is smaller than 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+            +
+            n
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}+n}}
+  
+ which is smaller than its own Hartogs number—this uses the equality 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+            +
+            n
+          
+        
+        
+        =
+        
+        2
+        ⋅
+        
+        
+          2
+          
+            
+              ℵ
+              
+                0
+              
+            
+            +
+            n
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{0}+n}\,=\,2\cdot \,2^{\aleph _{0}+n}}
+  
+; for the full proof, see Gillman.
+Kurt Gödel showed that GCH is a consequence of ZF + V=L (the axiom that every set is constructible relative to the ordinals), and is therefore consistent with ZFC. As GCH implies CH, Cohen's model in which CH fails is a model in which GCH fails, and thus GCH is not provable from ZFC. W. B. Easton used the method of forcing developed by Cohen to prove Easton's theorem, which shows it is consistent with ZFC for arbitrarily large cardinals 
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }}
+  
+ to fail to satisfy 
+  
+    
+      
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            α
+            +
+            1
+          
+        
+      
+    
+    {\displaystyle 2^{\aleph _{\alpha }}=\aleph _{\alpha +1}}
+  
+. Much later, Foreman and Woodin proved that (assuming the consistency of very large cardinals) it is consistent that 
+  
+    
+      
+        
+          2
+          
+            κ
+          
+        
+        >
+        
+          κ
+          
+            +
+          
+        
+      
+    
+    {\displaystyle 2^{\kappa }>\kappa ^{+}}
+  
+ holds for every infinite cardinal 
+  
+    
+      
+        κ
+      
+    
+    {\displaystyle \kappa }
+  
+. Later Woodin extended this by showing the consistency of 
+  
+    
+      
+        
+          2
+          
+            κ
+          
+        
+        =
+        
+          κ
+          
+            +
+            +
+          
+        
+      
+    
+    {\displaystyle 2^{\kappa }=\kappa ^{++}}
+  
+ for every 
+  
+    
+      
+        κ
+      
+    
+    {\displaystyle \kappa }
+  
+. Carmi Merimovich showed that, for each n ≥ 1, it is consistent  with ZFC that for each infinite cardinal κ, 2κ is the nth successor of κ (assuming the consistency of some large cardinal axioms). On the other hand, László Patai proved that if γ is an ordinal and for each infinite cardinal κ, 2κ is the γth successor of κ, then γ is finite.
+For any infinite sets A and B, if there is an injection from A to B then there is an injection from subsets of A to subsets of B. Thus for any infinite cardinals A and B, 
+  
+    
+      
+        A
+        <
+        B
+        →
+        
+          2
+          
+            A
+          
+        
+        ≤
+        
+          2
+          
+            B
+          
+        
+      
+    
+    {\displaystyle A<B\to 2^{A}\leq 2^{B}}
+  
+. If A and B are finite, the stronger inequality 
+  
+    
+      
+        A
+        <
+        B
+        →
+        
+          2
+          
+            A
+          
+        
+        <
+        
+          2
+          
+            B
+          
+        
+      
+    
+    {\displaystyle A<B\to 2^{A}<2^{B}}
+  
+ holds. GCH implies that this strict, stronger inequality holds for infinite cardinals as well as finite cardinals.
+
+=== Implications of GCH for cardinal exponentiation ===
+Although the generalized continuum hypothesis refers directly only to cardinal exponentiation with 2 as the base, one can deduce from it the values of cardinal exponentiation 
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}}
+  
+ in all cases. GCH implies that for ordinals α and β:
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            β
+            +
+            1
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}=\aleph _{\beta +1}}
+  
+ when α ≤ β+1;
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            α
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}=\aleph _{\alpha }}
+  
+ when β+1 < α and 
+  
+    
+      
+        
+          ℵ
+          
+            β
+          
+        
+        <
+        cf
+        ⁡
+        (
+        
+          ℵ
+          
+            α
+          
+        
+        )
+      
+    
+    {\displaystyle \aleph _{\beta }<\operatorname {cf} (\aleph _{\alpha })}
+  
+, where cf is the cofinality operation; and
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            α
+            +
+            1
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}=\aleph _{\alpha +1}}
+  
+ when β+1 < α and 
+  
+    
+      
+        
+          ℵ
+          
+            β
+          
+        
+        ≥
+        cf
+        ⁡
+        (
+        
+          ℵ
+          
+            α
+          
+        
+        )
+      
+    
+    {\displaystyle \aleph _{\beta }\geq \operatorname {cf} (\aleph _{\alpha })}
+  
+.
+The first equality (when α ≤ β+1) follows from:
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        ≤
+        
+          ℵ
+          
+            β
+            +
+            1
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        (
+        
+          2
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        
+          )
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                β
+              
+            
+            ⋅
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            β
+            +
+            1
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}\leq \aleph _{\beta +1}^{\aleph _{\beta }}=(2^{\aleph _{\beta }})^{\aleph _{\beta }}=2^{\aleph _{\beta }\cdot \aleph _{\beta }}=2^{\aleph _{\beta }}=\aleph _{\beta +1}}
+  
+
+while:
+
+  
+    
+      
+        
+          ℵ
+          
+            β
+            +
+            1
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        ≤
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        .
+      
+    
+    {\displaystyle \aleph _{\beta +1}=2^{\aleph _{\beta }}\leq \aleph _{\alpha }^{\aleph _{\beta }}.}
+  
+
+The third equality (when β+1 < α and 
+  
+    
+      
+        
+          ℵ
+          
+            β
+          
+        
+        ≥
+        cf
+        ⁡
+        (
+        
+          ℵ
+          
+            α
+          
+        
+        )
+      
+    
+    {\displaystyle \aleph _{\beta }\geq \operatorname {cf} (\aleph _{\alpha })}
+  
+) follows from:
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        ≥
+        
+          ℵ
+          
+            α
+          
+          
+            cf
+            ⁡
+            (
+            
+              ℵ
+              
+                α
+              
+            
+            )
+          
+        
+        >
+        
+          ℵ
+          
+            α
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}\geq \aleph _{\alpha }^{\operatorname {cf} (\aleph _{\alpha })}>\aleph _{\alpha }}
+  
+
+by Kőnig's theorem, while:
+
+  
+    
+      
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                β
+              
+            
+          
+        
+        ≤
+        
+          ℵ
+          
+            α
+          
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        ≤
+        (
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        
+          )
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+            ⋅
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        =
+        
+          2
+          
+            
+              ℵ
+              
+                α
+              
+            
+          
+        
+        =
+        
+          ℵ
+          
+            α
+            +
+            1
+          
+        
+      
+    
+    {\displaystyle \aleph _{\alpha }^{\aleph _{\beta }}\leq \aleph _{\alpha }^{\aleph _{\alpha }}\leq (2^{\aleph _{\alpha }})^{\aleph _{\alpha }}=2^{\aleph _{\alpha }\cdot \aleph _{\alpha }}=2^{\aleph _{\alpha }}=\aleph _{\alpha +1}}
+  
+
+== See also ==
+Absolute infinite
+Beth number
+Cardinality
+Ω-logic
+Second continuum hypothesis
+Wetzel's problem
+
+== References ==
+ 
+Maddy, Penelope (June 1988). "Believing the axioms, [part I]". Journal of Symbolic Logic. 53 (2). Association for Symbolic Logic: 481–511. doi:10.2307/2274520. JSTOR 2274520.
+
+== Sources ==
+This article incorporates material from Generalized continuum hypothesis on PlanetMath, which is licensed under the Creative Commons Attribution/Share-Alike License. Archived 2017-02-08 at the Wayback Machine
+
+== Further reading ==
+Cohen, Paul Joseph (2008) [1966]. Set theory and the continuum hypothesis. Mineola, New York City: Dover Publications. ISBN 978-0-486-46921-8.
+Dales, H.G.; Woodin, W.H. (1987). An Introduction to Independence for Analysts. Cambridge.
+Enderton, Herbert (1977). Elements of Set Theory. Academic Press.
+Gödel, K.: What is Cantor's Continuum Problem?, reprinted in Benacerraf and Putnam's collection Philosophy of Mathematics, 2nd ed., Cambridge University Press, 1983. An outline of Gödel's arguments against CH.
+Martin, D. (1976). "Hilbert's first problem: the continuum hypothesis," in Mathematical Developments Arising from Hilbert's Problems, Proceedings of Symposia in Pure Mathematics XXVIII, F. Browder, editor. American Mathematical Society, 1976, pp. 81–92. ISBN 0-8218-1428-1
+McGough, Nancy. "The Continuum Hypothesis".
+Wolchover, Natalie (15 July 2021). "How Many Numbers Exist? Infinity Proof Moves Math Closer to an Answer".
+
+== External links ==
+ Quotations related to Continuum hypothesis at Wikiquote
+
+Szudzik, Matthew & Weisstein, Eric W. "Continuum Hypothesis". MathWorld.

data/en.wikipedia.org/wiki/Cosmic_censorship_hypothesis-0.md

@@ -0,0 +1,269 @@
+---
+title: "Cosmic censorship hypothesis"
+chunk: 1/2
+source: "https://en.wikipedia.org/wiki/Cosmic_censorship_hypothesis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T09:59:16.959067+00:00"
+instance: "kb-cron"
+---
+
+The weak and the strong cosmic censorship hypotheses are two mathematical conjectures about the structure of gravitational singularities in the context of general relativity.
+Singularities that arise in the solutions of Einstein's equations are typically hidden within event horizons, and therefore cannot be observed from the rest of spacetime. Singularities that are not so hidden are called naked. The weak cosmic censorship hypothesis was conceived by Roger Penrose in 1969 and posits that no naked singularities is visible from infinity (namely, it is “dressed” by an event horizon) while the strong cosmic censorship hypothesis asserts that generically, general relativity must be a deterministic theory and, thus, our universe must be globally hyperbolic.
+
+== Basics ==
+Since the physical behavior of singularities is unknown, if singularities can be observed from the rest of spacetime, causality may break down, and physics may lose its predictive power. The issue cannot be avoided, since according to the Penrose–Hawking singularity theorems, singularities are inevitable in physically reasonable situations. Still, in the absence of naked singularities, the universe, as described by the general theory of relativity, is deterministic: it is possible to predict the entire evolution of the universe (possibly excluding some finite regions of space hidden inside event horizons of singularities), knowing only its condition at a certain moment of time (more precisely, everywhere on a spacelike three-dimensional hypersurface, called the Cauchy surface). Failure of the cosmic censorship hypothesis leads to the failure of determinism, because it is yet impossible to predict the behavior of spacetime in the causal future of a singularity. Cosmic censorship is not merely a problem of formal interest; some form of it is assumed whenever black hole event horizons are mentioned.
+
+The hypothesis was first formulated by Roger Penrose in 1969, and it is not stated in a completely formal way. In a sense it is more of a research program proposal: part of the research is to find a proper formal statement that is physically reasonable, falsifiable, and sufficiently general to be interesting.  Because the statement is not a strictly formal one, there is sufficient latitude for (at least) two independent formulations: a weak form, and a strong form.
+
+== Weak and strong cosmic censorship hypothesis ==
+The weak and the strong cosmic censorship hypotheses are two conjectures concerned with the global geometry of spacetimes.
+The weak cosmic censorship hypothesis asserts there can be no singularity visible from future null infinity. In other words, singularities need to be hidden from an observer at infinity by the event horizon of a black hole. Mathematically, the conjecture states that, for generic initial data, the causal structure is such that the maximal Cauchy development possesses a complete future null infinity.
+The strong cosmic censorship hypothesis asserts that, generically, general relativity is a deterministic theory, in the same sense that classical mechanics is a deterministic theory. In other words, the classical fate of all observers should be predictable from the initial data. Mathematically, the conjecture states that the maximal Cauchy development of generic compact or asymptotically flat initial data is locally extensible as a regular Lorentzian manifold. Taken in its strongest sense, the conjecture suggests the local extensibility of the maximal Cauchy development as a continuous Lorentzian manifold (very strong cosmic censorship). This strongest version was disproven in 2018 by Mihalis Dafermos and Jonathan Luk for the Cauchy horizon of an uncharged, rotating black hole. 
+The two conjectures are mathematically independent, as there exist spacetimes for which weak cosmic censorship is valid but strong cosmic censorship is violated and, conversely, there exist spacetimes for which weak cosmic censorship is violated but strong cosmic censorship is valid.
+
+== Example ==
+The Kerr metric, corresponding to a black hole of mass 
+  
+    
+      
+        M
+      
+    
+    {\displaystyle M}
+  
+ and angular momentum 
+  
+    
+      
+        J
+      
+    
+    {\displaystyle J}
+  
+, can be used to derive the effective potential for particle orbits restricted to the equator (as defined by rotation).  This potential looks like:
+
+  
+    
+      
+        
+          V
+          
+            
+              e
+              f
+              f
+            
+          
+        
+        (
+        r
+        ,
+        e
+        ,
+        ℓ
+        )
+        =
+        −
+        
+          
+            M
+            r
+          
+        
+        +
+        
+          
+            
+              
+                ℓ
+                
+                  2
+                
+              
+              −
+              
+                a
+                
+                  2
+                
+              
+              (
+              
+                e
+                
+                  2
+                
+              
+              −
+              1
+              )
+            
+            
+              2
+              
+                r
+                
+                  2
+                
+              
+            
+          
+        
+        −
+        
+          
+            
+              M
+              (
+              ℓ
+              −
+              a
+              e
+              
+                )
+                
+                  2
+                
+              
+            
+            
+              r
+              
+                3
+              
+            
+          
+        
+        ,
+         
+         
+         
+        a
+        ≡
+        
+          
+            J
+            M
+          
+        
+      
+    
+    {\displaystyle V_{\rm {eff}}(r,e,\ell )=-{\frac {M}{r}}+{\frac {\ell ^{2}-a^{2}(e^{2}-1)}{2r^{2}}}-{\frac {M(\ell -ae)^{2}}{r^{3}}},~~~a\equiv {\frac {J}{M}}}
+  
+
+where 
+  
+    
+      
+        r
+      
+    
+    {\displaystyle r}
+  
+ is the coordinate radius, 
+  
+    
+      
+        e
+      
+    
+    {\displaystyle e}
+  
+ and 
+  
+    
+      
+        ℓ
+      
+    
+    {\displaystyle \ell }
+  
+ are the test-particle's conserved energy and angular momentum respectively (constructed from the Killing vectors).
+To preserve cosmic censorship, the black hole is restricted to the case of 
+  
+    
+      
+        a
+        <
+        1
+      
+    
+    {\displaystyle a<1}
+  
+.  For there to exist an event horizon around the singularity, the requirement 
+  
+    
+      
+        a
+        <
+        1
+      
+    
+    {\displaystyle a<1}
+  
+ must be satisfied.  This amounts to the angular momentum of the black hole being constrained to below a critical value, outside of which the horizon would disappear.  
+The following thought experiment is reproduced from Hartle's Gravity:
+
+Imagine specifically trying to violate the censorship conjecture.  This could be done by somehow imparting an angular momentum upon the black hole, making it exceed the critical value (assume it starts infinitesimally below it).  This could be done by sending a particle of angular momentum 
+  
+    
+      
+        ℓ
+        =
+        2
+        M
+        e
+      
+    
+    {\displaystyle \ell =2Me}
+  
+.  Because this particle has angular momentum, it can only be captured by the black hole if the maximum potential of the black hole is less than 
+  
+    
+      
+        (
+        
+          e
+          
+            2
+          
+        
+        −
+        1
+        )
+        
+          /
+        
+        2
+      
+    
+    {\displaystyle (e^{2}-1)/2}
+  
+.
+Solving the above effective potential equation for the maximum under the given conditions results in a maximum potential of exactly 
+  
+    
+      
+        (
+        
+          e
+          
+            2
+          
+        
+        −
+        1
+        )
+        
+          /
+        
+        2
+      
+    
+    {\displaystyle (e^{2}-1)/2}
+  
+.  Testing other values shows that no particle with enough angular momentum to violate the censorship conjecture would be able to enter the black hole, because they have too much angular momentum to fall in.
+
+== Problems with the concept ==
+There are a number of difficulties in formalizing the hypothesis: