Is Strong Reciprocity a Maladaptation? On the Evolutionary Foundations of Human Altruism.

Summary of: Is Strong Reciprocity a Maladaptation? On the Evolutionary Foundations of Human Altruism.

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Evidence is cited that strong reciprocity (repaying cooperation and punishing defection, cheating, violation of fairness norms), which plays a role in the provision of public goods and contradicts theories of selfish actors, is neither a maladaptation, nor explained in an evolutionary context by kin selection, reciprocal altruism, indirect reciprocity, or costly signaling.

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MIT Press in Cooperation with Dahlem University Press


  • Humans repay gifts and punish cheaters of cooperation and fairness norms, even in anonymous, one-shot encounters with genetically unrelated strangers (strong reciprocity) – contrary to theories that all humans are strictly rational and strictly self-interested actors -- and evidence suggests that the presence of a high number of strong reciprocators in human groups was an evolutionary advantage.
  • Strong reciprocity plays a decisive role in the production of public goods – strong reciprocity in the provision of public goods is enabled by the metanorm of altruistic punishment, which makes possible the maintenance of norms that are good for groups at a cost to individuals.

Economic games that probe of human behavior (including games that allow punishment of cheaters and non-reciprocators), together with research by biologists, zoologists, and primatologists have delivered strong evidence that traditional assumptions of universally strictly egoistic (rationally self-interested) behavior are at least partially wrong: People repay gifts and punish cheaters, even at a cost to themselves, even among strangers in one-shot games where there is not possibility of reaping future repayment. This practice of "strong reciprocity" has been explained evolutionarily as a maladaptation. The authors of this survey marshal evidence that theories of kin selection (altruism on behalf of genetic relatives that provides reproductive advantage to those who share the altruist's genes), reciprocal altruism (gifts that are made with expectation of eventual repayment by the giftee), indirect reciprocity (gaining a reputation that could pay off in future encounters with other members of the group) costly signaling (acts that cost the actor, but which signal desirability of the signaler as a potential ally or mate) do not sufficiently explain strong reciprocity – and evidence that contradicts these theories as explanatory mechanisms. A cultural evolution hypothesis is proposed: groups that are not closely genetically related can gain survival advantage in competition with other groups if a disproportionate number of strong reciprocators are present – and the presence of strong reciprocators is only possible when cheaters are punished. At the same time, other selection pressures drive the presence of purely selfish humans. Both types coexist because they have coevolved in human cultural practice. The authors offer a beginning, not an ultimate answer, to questions about strong reciprocity, suggesting further research.