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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Biology of romantic love | 6/14 | https://en.wikipedia.org/wiki/Biology_of_romantic_love | reference | science, encyclopedia | 2026-05-05T15:53:39.742070+00:00 | kb-cron |
The early stage of romantic love is being compared to a behavioral addiction (i.e., addiction to a non-substance) but the "substance" involved is the loved person. Addiction involves a phenomenon known as incentive salience, also called "wanting" (in quotes). This is the property by which cues in the environment stand out to a person and become attention-grabbing and attractive, like a "motivational magnet" which pulls a person towards a particular reward. Incentive salience differs from craving in that craving is a conscious experience while incentive salience may or may not be. While incentive salience can give feelings of strong urgency to cravings, it can also motivate behavior unconsciously, as in an experiment where cocaine users were unaware of their own decisions to choose a low dose of cocaine (which they believed was placebo) more often than an actual placebo. In the incentive-sensitization theory of addiction, repeated drug use renders the brain hypersensitive to drugs and drug cues, resulting in pathological levels of "wanting" to use drugs. People in love are thought to experience incentive salience in response to their beloved. Lovers share other similarities with addicts as well, like tolerance, dependence, withdrawal, relapse, craving, and mood modification. Incentive salience is mediated by dopamine projections in the mesocorticolimbic pathway of the brain, an area generally involved with reward, motivation, and reinforcement learning. Dopamine signaling for incentive salience originates in the ventral tegmental area (VTA) and projects to areas such as the nucleus accumbens (NAc) in the ventral striatum. The VTA is one of two main areas of the brain with neurons which produce dopamine (the other being the substantia nigra pars compacta). Projections from the VTA innervate the NAc, where dopamine activity attaches motivational significance to stimuli associated with rewards. Brain scans of people in love using fMRI (commonly while looking at a photograph of their beloved) show activations in these areas like the VTA and NAc. Another dopamine-rich area of the reward system shown to be active in romantic love is the caudate nucleus, containing 80% of the brain's dopamine receptor sites, located in the dorsal striatum. The dorsal striatum is implicated in reinforcement learning, and the caudate nucleus has shown activity in response to a monetary reward and cocaine. This activity in reward and motivation areas suggests that early-stage intense romantic love is a motivation system or goal-oriented state (rather than a specific emotion), consistent with the description of romantic love as a desire or longing for union with another person. These activations are also consistent with the similarity between romantic love and addiction. In addiction research, a distinction is drawn between "wanting" a reward (i.e., incentive salience, tied to mesocorticolimbic dopamine) and "liking" a reward (i.e., pleasure, tied to hedonic hotspots), aspects which are dissociable. People can be addicted to drugs and compulsively seek them out, even when taking the drug no longer results in a high or the addiction is detrimental to one's life. They can also irrationally "want" (i.e. feel compelled towards, in the sense of incentive salience) something which they do not cognitively wish for. In a similar way, people who are in love may "want" a loved person even when interactions with them are not pleasurable. For example, they may want to contact an ex-partner after a rejection, even when the experience will only be painful. It is also possible for a person to be "in love" with somebody they do not like, or who treats them poorly. Academics have proposed a number of theories for how addictions begin and perpetuate. One prominent theory developed by Wolfram Schultz involves a dopamine signal which encodes a reward prediction error (RPE): the difference between the predicted value of a reward, which would be received by performing a particular action, and the actual value upon receiving it: whether the reward was better, equal to or worse than expected. In this theory, dopamine is also part of a mechanism for reinforcement learning which associates rewards with the cues which predicted them. Drugs of abuse like cocaine hijack this mechanism by artificially overstimulating dopamine neurons, mimicking an RPE signal which is much stronger than could be produced naturally. An alternative model developed by Kent Berridge and Terry Robinson states that dopamine signaling causes the motivational output (incentive salience) which is proportional to RPE, but that the dopamine signal itself may be an effect of learning rather than causing it directly. There is, however, said to be overwhelming evidence that dopamine guides learning in addition to motivation. The computation of dopamine signaling is complicated, with inputs from a variety of areas in the brain, although its output (primarily from the VTA) is a relatively homogeneous signal encoding the level of RPE. One study has investigated whether people in long-term romantic relationships experienced RPE in response to having expectations about their partners' appraisal of them validated or violated, indicating they do. This study used fMRI to find that reward areas like the VTA and striatum responded in a way consistent with other research on RPE. Most fMRI studies of romantic love have had participants look at a photograph, and the resulting reward system activity has been interpreted in terms of salience. Research has not investigated whether romantic love shares all of the neurobiological aspects of addiction. Despite similarities, there are also differences between romantic love and addiction. One of the major differences is that the trajectories diverge, with the addictive aspects tending to disappear over time during a relationship in romantic love. By comparison, in a drug addiction, the detrimental aspects magnify over time with repeated drug use, turning into compulsions, a loss of control and a negative emotional state. It has been speculated that the difference between these could be related to oxytocin activity present in romantic love, but not in addiction. Oxytocin seems to ameliorate the effects of drug withdrawal, and it might inhibit the more long-term, excessive effects of addiction. Academics do not universally agree on whether or not love is always an addiction or when it needs to be treated. The term "love addiction" has had an amorphous definition over the years and does not yet denote a psychiatric condition, but recently one definition has been developed that "Individuals addicted to love tend to experience negative moods and affects when away from their partners and have the strong urge and craving to see their partner as a way of coping with stressful situations." Other authors include rejected lovers as love addicts, or specify that love is an addiction when it involves abnormal processes which carry negative consequences. A broader view is that all love is addiction, or simply an appetite, similar to how humans are dependent on food. Research on behavioral addictions is more limited than research on drugs of abuse; however, there is a growing body of evidence that some people are susceptible to showing brain patterns in response to natural rewards (food, sex, etc.) similar to drug addicts, particularly in the case of gambling addiction. Romantic love may be a "natural" addiction, which differs from the nature of drug addiction in that love may be prosocial and has been evolved for the purpose of pair bonding.