Evolutionary Psychology and the Social Sciences

Summary of: Evolutionary Psychology and the Social Sciences

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Evolutionary psychology helps us link up the Darwinian story of cooperation in nature, of kin selection, cooperation for mutual advantage, reciprocal altruism, and group selection, with the familiar story of the development of human societies, of property rights, nations, banks, and charity, without implying that such a connection could morally justify or perfectly determine human behavior.

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Humane Studies Review
October 2000


  • "Studying animal behavior and cooperation, therefore, is useful in the same way that game theory is useful, to provide evidence of how humans might be predicted to act absent the restraints of human nature and social institutions and norms."
  • "Compassion and sympathy toward those who are unable to help themselves appear to be as much a part of human nature as the unwillingness to feel much sympathy for shirkers who subsequently seek to share in the social product."

Evolutionary psychology has been portrayed as justifying or implying a lot of bad ideas in the 20th century, but it need not suffer from these mistaken linkages and can potentially shed light on how to build better social institutions. Although the claim has been made, evolutionary psychology is not consistent with the tenets of Social Darwinism. Whether a trait or behavior survives the process of natural or cultural selection has no bearing over our discourse on whether it is morally justified. Nor does it mean that we are determined like machines to act out these behaviors in every case, a theory termed 'behavioral determinism' by those criticizing evolutionary psychology or its earlier form, sociobiology. Any reputable biologist, or sociobiologist, would acknowledge that the fitness of a behavioral trait is dependent on the interaction between that trait and a given environment, so saying that a certain psychological predisposition in humans is the product of an evolutionary process does not mean that it is good, justifiable or useful in the world we live in. Evolutionary science stresses that fitness is fundamentally contingent. Furthermore, humans have a cultural inheritance that dictates in subtle ways how and when we should express or repress our behavioral traits, making the interaction between trait and environment even more complex. Evolutionary psychologists suggest that we pay close attention to the basic human behaviors that through cross-cultural analysis appear 'hard-wired', because it is these behaviors, such as sympathy for those in pain or identification with one's kin or tribe, that we want to either channel or suppress in order to reap the benefits of cooperation.

This article isolates four mechanisms that promote cooperation in the absence of a central authority: kin selection, cooperation for mutual advantage, reciprocal altruism, and group selection. Kin selection implies a kind of utilitarian genetic calculus, that sacrificing one's life for the right number of relatives will be favorable for one's genes. A sibling shares on average half of one's genes, so sacrificing one's life for two or more siblings makes evolutionary sense. An example of a behavior that might be explained by kin selection is the warning call of ground squirrels; a ground squirrel that notices a hawk circling will call out to warn its family, although it increases its likelihood of being noticed and eaten by the hawk. This form of cooperation requires enough brain or nose power to be able to determine who is a relative.

The second form, cooperation for mutual advantage, occurs when a particular given end (critical for survival) is easier to accomplish with a group working together. The quintessential example of this mechanism is group hunting; wolves (and our hunter-gatherer ancestors) hunt in packs because they will end up with a portion of the large game, which can be much larger than the small game they would be able to catch on their own and not have to share. This benefits of this mechanism is not as immediate or certain as those of kin selection, because the stronger hunters could potentially share nothing with the weak who helped. This article cites field studies of monkeys, lions, and fish, which show that group hunting generally only occurs when environmental conditions make it economically more efficient that hunting alone. While cooperation for mutual advantage is an important surplus-generating mechanism in nature, we should not expect this mechanism to form the basis of modern human cooperation. Modern human cooperation cannot be pared down to a single one-shot end, and it could be argued the developments of civilization we are most proud of, charity for the poor or sick, go against the logic of mutual advantage.

Reciprocal altruism looks similar to the mechanism of mutual advantage, except the benefits are spread over time rather than through a single interaction. One individual helps another individual with the expectation that in the future the gesture will be repaid. Reciprocal altruism works best when developed alongside "a large number of supplementary psychological and social institutions." Enduring reputation and social traditions such as gift-giving foster relationships of reciprocal altruism. This kind of a relationship requires a bigger brain to remember who gave you what and who has mooched off you for too long, but can generate a big societal payoff. "By allowing trade over a period of time, reciprocal altruism opens up the possibility of a division of labor and credit-based relationships. These innovations make possible the recognition of the gains from specialization, comparative advantage, and the insurance and risk-shifting elements of inter-temporal trade."

While reciprocal altruism is most compelling in small groups with face-to-face interaction, the final mechanism, group selection, treats populations as the unit of measure. Proponents of group selection argue that a population of individuals with altruistic traits would fare better than less altruistic populations, reaching the big payoffs described in the above paragraph. The traits in question could be genetically inherited or culturally inherited. Arguing for cultural group selection, "[g]roups that adopt 'better' cultural practices will again tend to grow healthier, wealthier, and more populous, gradually supplanting less efficient cultures through conquest, migration, or conscious adoption." This kind of cooperation requires even more specific conditions than the other three mechanisms. Because the scale of group selection is so much larger than the other mechanisms, it is still a controversial theory in natural and social sciences. The argument against cultural and biological group selection is based on problem of free riders without altruistic traits who might take advantage of the social surplus generated by their altruistic neighbors. While human populations have reached impressive levels of cooperation in modern societies, one can imagine natural disasters or devastating world wars that would eliminate the evolutionary strength of group selection.