December 13, 2006
In a Science Magazine article entitled, Group Competition, Reproductive Leveling, and the Evolution of Human Altruism Samuel Bowles tries to resurrect the formerly discredited concept of group selection. Critics of group selection argued that egoist traits would in the end drive altruist traits out of existence because bearers of altruistic traits would not have as many off-spring as the bearers of egoistic traits, who only care about their genetic kin. With the help of a simulation model, Bowles deduces under what conditions early humans had to live for group selection to have been responsible for diffusion of altruistic traits among human populations.
Abstract of Article:
Humans behave altruistically in natural settings and experiments. A possible explanation—that groups with more altruists survive when groups compete—has long been judged untenable on empirical grounds for most species. But there have been no empirical tests of this explanation for humans. My empirical estimates show that genetic differences between early human groups are likely to have been great enough so that lethal intergroup competition could account for the evolution of altruism. Crucial to this process were distinctive human practices such as sharing food beyond the immediate family, monogamy, and other forms of reproductive leveling. These culturally transmitted practices presuppose advanced cognitive and linguistic capacities, possibly accounting for the distinctive forms of altruism found in our species.
Full Text: http://www.sciencemag.org/cgi/content/full/314/5805/1569
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