Vonk, J., S. F. Brosnan, J. B. Silk, J. Henrich, A. S. Richardson, S. P. Lambeth, S. J. Schapiro, and D. J. Povinelli. “
Chimpanzees do not take advantage of very low cost opportunities to deliver food to unrelated group members.”
Animal Behaviour 75, no. 5 (2008): 1757-1770.
AbstractWe conducted experiments on two populations of chimpanzees, Pan troglodytes, to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social groups. We compared the chimpanzees' behaviour when they were paired with another chimpanzee and when they were alone. If chimpanzees are motivated to provide benefits to others, they are expected to consistently deliver rewards to others and to distinguish between the partner-present and partner-absent conditions. Results from both experiments indicate that our subjects were largely indifferent to the benefits they could provide to others. They were less likely to provide rewards to potential recipients as the experiment progressed, and all but one of the 18 subjects were as likely to deliver rewards to an empty enclosure as to an enclosure housing another chimpanzee. These results, in conjunction with similar results obtained in previous experiments, suggest that chimpanzees are not motivated by prosocial sentiments to provide food rewards to other group members. The Association for the Study of Animal Behaviour. Published by Elsevier Ltd.
PDF Henrich, Joseph, Robert Boyd, and Peter J Richerson. “
Five misunderstandings about cultural evolution.”
Human Nature 19, no. 2 (2008): 119-137.
PDF Marlowe, F., J. C. Berbesque, A. Barr, C. Barrett, A. Bolyanatz, J. C. Cardenas, J. Ensminger, et al. “
More ‘altruistic’ punishment in larger societies.”
Proceedings of the Royal Society B: Biological Sciences 275, no. 1634 (2008): 587-590.
AbstractIf individuals will cooperate with cooperators, and punish non-cooperators even at a cost to themselves, then this strong reciprocity could minimize the cheating that undermines cooperation. Based upon numerous economic experiments, some have proposed that human cooperation is explained by strong reciprocity and norm enforcement. Second-party punishment is when you punish someone who defected on you; third-party punishment is when you punish someone who defected on someone else. Third-party punishment is an effective way to enforce the norms of strong reciprocity and promote cooperation. Here we present new results that expand on a previous report from a large cross-cultural project. This project has already shown that there is considerable cross-cultural variation in punishment and cooperation. Here we test the hypothesis that population size (and complexity) predicts the level of third-party punishment. Our results show that people in larger, more complex societies engage in significantly more third-party punishment than people in small-scale societies.
PDF Gintis, H., J. Henrich, S. Bowles, R. Boyd, and E. Fehr. “
Strong reciprocity and the roots of human morality.”
Social Justice Research 21, no. 2 (2008): 241-253.
AbstractHuman morality is a key evolutionary adaptation on which human social behavior has been based since the Pleistocene era. Ethical behavior is constitutive of human nature, we argue, and human morality is as important an adaptation as human cognition and speech. Ethical behavior, we assert, need not be a means toward personal gain. Because of our nature as moral beings, humans take pleasure in acting ethically and are pained when acting unethically. From an evolutionary viewpoint, we argue that ethical behavior was fitness-enhancing in the years marking the emergence of Homo sapiens because human groups with many altruists fared better than groups of selfish individuals, and the fitness losses sustained by altruists were more than compensated by the superior performance of the groups in which they congregated.
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