Scientific American: On the Origin of Cooperative Species: New study reverses a decade of research claiming chimpanzee selfishness (http://l.ravi.be/nc2xPE):
> Based on these kinds of negative findings researchers in the social sciences and humanities boldly concluded that humans were the only species capable of engaging in altruistic or prosocial behavior. Just this year, famed cultural anthropologistMarshall Sahlins wrote that, “non-human primates live by themselves and for themselves” while the economists Ernst Fehr and Urs Fischbacher wrote in a review article for Nature that prosocial behavior in nonhuman animals is “largely restricted to kin groups” making human societies “a huge anomaly in the animal world.” The economists Samuel Bowles and Herbert Gintis even went so far as to claim “human cooperation is the result of human capacities that are unique to our species.”
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> As Carl Sagan famously wrote, “Absence of evidence is not evidence of absence.” In a clear illustration of this dictum, Horner and De Waal determined that it was not that chimpanzees are motivated only by selfishness as these earlier reports contended. The tests that were designed to measure chimpanzee behavior were overly complicated and resulted in false conclusions.
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> “The chimps had to understand a complex food-delivery system,” De Waal wrote to me via e-mail, “and were often placed so far apart that they may not have realized how their actions benefited others. Our experiment is the first to avoid an apparatus altogether. Of course, our study also provides a warning against negative findings.”
—ravi