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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| American anthropology | 2/15 | https://en.wikipedia.org/wiki/American_anthropology | reference | science, encyclopedia | 2026-05-05T14:59:05.969182+00:00 | kb-cron |
(a) the creation and use of conventional symbols, including linguistic symbols and their derivatives, such as written language and mathematical symbols and notations; (b) the creation and use of complex tools and other instrumental technologies; and (c) the creation and participation in complex social organization and institutions. According to developmental psychologist Michael Tomasello, "where these complex and species-unique behavioral practices, and the cognitive skills that underlie them, came from" is a fundamental anthropological question. Given that contemporary humans and chimpanzees are far more different from horses and zebras, or rats and mice, and that the evolution of this great difference occurred in such a short period of time, "our search must be for some small difference that made a big difference – some adaptation, or small set of adaptations, that changed the process of primate cognitive evolution in fundamental ways." According to Tomasello, the answer to this question must form the basis of a scientific definition of "human culture." In a recent review of the major research on human and primate tool-use, communication, and learning strategies, Tomasello argues that the key human advances over primates (language, complex technologies, and complex social organization) are all the results of humans pooling cognitive resources. This is called "the ratchet effect:" innovations spread and are shared by a group, and mastered "by youngsters, which enables them to remain in their new and improved form within the group until something better comes along." The key point is that children are born good at a particular kind of social learning; this creates a favored environment for social innovations, making them more likely to be maintained and transmitted to new generations than individual innovations. For Tomasello, human social learning—the kind of learning that distinguishes humans from other primates and that played a decisive role in human evolution—is based on two elements: first, what he calls "imitative learning," (as opposed to "emulative learning" characteristic of other primates) and second, the fact that humans represent their experiences symbolically (rather than iconically, as is characteristic of other primates). Together, these elements enable humans to be both inventive, and to preserve useful inventions. It is this combination that produces the ratchet effect.
The kind of learning found among other primates is "emulation learning," which "focuses on the environmental events involved – results or changes of state in the environment that the other produced – rather than on the actions that produced those results." Tomasello emphasizes that emulation learning is a highly adaptive strategy for apes because it focuses on the effects of an act. In laboratory experiments, chimpanzees were shown two different ways for using a rake-like tool to obtain an out-of-reach-object. Both methods were effective, but one was more efficient than the other. Chimpanzees consistently emulated the more efficient method. Examples of emulation learning are well documented among primates. Notable examples include Japanese macaque potato washing, chimpanzee tool use, and chimpanzee gestural communication. In 1953, an 18-month-old female macaque monkey was observed taking sandy pieces of sweet potato (given to the monkeys by observers) to a stream (and later, to the ocean) to wash off the sand. After three months, the same behavior was observed in her mother and two playmates, and then the playmates' mothers. Over the next two years seven other young macaques were observed washing their potatoes, and by the end of the third year 40% of the troop had adopted the practice. Although this story is popularly represented as a straightforward example of human-like learning, evidence suggests that it is not. Many monkeys naturally brush sand off food; this behavior had been observed in the macaque troop prior to the first observed washing. Moreover, potato washing was observed in four other separate macaque troops, suggesting that at least four other individual monkeys had learned to wash off sand on their own. Other monkey species in captivity quickly learn to wash off their food. Finally, the spread of learning among the Japanese macaques was fairly slow, and the rate at which new members of the troop learned did not keep pace with the growth of the troop. If the form of learning were imitation, the rate of learning should have been exponential. It is more likely that the monkeys' washing behavior is based on the common behavior of cleaning off food, and that monkeys that spent time by the water independently learned to wash, rather than wipe their food. This explains both why those monkeys that kept company with the original washer, and who thus spent a good deal of time by the water, also figured out how to wash their potatoes. It also explains why the rate at which this behavior spread was slow. Chimpanzees exhibit a variety of population-specific tool use: termite-fishing, ant-fishing, ant-dipping, nut-cracking, and leaf-sponging. Gombe Chimpanzees fish for termites using small, thin sticks, but chimpanzees in Western Africa use large sticks to break holes in mounds and use their hands to scoop up termites. Some of this variation may be the result of "environmental shaping" (there is more rainfall in western Africa, softening termite mounds and making them easier to break apart, than in the Gombe reserve in eastern Africa). Nevertheless, it is clear that chimpanzees are good at emulation learning. Chimpanzee children independently know how to roll over logs, and know how to eat insects. When children see their mothers rolling over logs to eat the insects beneath, they quickly learn to do the same. In other words, this form of learning builds on activities the children already know.