Invited Review: Biological adaptation and social behaviour

Abstract

In 1930, both Fisher and Wright identified Darwin's initial concept of adaptive evolution in the light of the genetical theory with intergenerational variation in allelic frequencies brought about by the action of natural selection through differential reproduction. They emphasized that selection only works at the level of the individual and that its only consequence is to increase fitness. One genetical evolution not easy to explain on these bases was that of social behaviour because any altruistic gene disadvantageous for its carriers in an asocial environment would have been opposed by selection. In the 1950s, ethologists focusing on what appeared to be evolved collective behaviours, hypothesized that selection could operate at group level. Though the controversy between group selectionists and evolutionary geneticists ended by the rejection of the evolutionary role of group selection, it has remained a subject of investigation until now. Kin selection, proposed by Hamilton, offered a solution to the problem of the evolution of altruism and gave the impetus to the trend of adaptive explanations of basic behaviours, which was to become the core of human sociobiology. The intrusion of behaviour into the process of adaptive evolution was an invitation to investigate culture as an evolutive process. The first sociobiological interpretations of culture as a derivative of genetic processes were followed by other ideas in which culture, though channelled by evolved predispositions, was essentially free from biological determinism. It is concluded that as we have come to better understand human adaptation, its complexities have been further revealed, a development already implicit in Darwin's notion.