Purposive Social Selection and the Evolution of Human Altruism

Normally scientific evolutionary approaches eschew any element of teleology in theorizing about how natural selection processes work, but social decisions pose a problem for this position. This article examines both positive and negative social sanctioning by human groups to show that purposive social selection at the level of phenotype can have parallel effects at the level of genotype, and that social control has shaped human genetic nature profoundly. A small cross-cultural sample of Pleistocene-appropriate foragers is used to suggest that human groups have been favoring generous individuals, for at least 45,000 years, in ways that affect their fitness. The impact on gene pools could have been substantial, given that runaway selection is likely to have been involved. This type of explanation, which takes human purposes into account as part of evolutionary process, offers a new solution for the genetic paradox of altruistic behavior.