ABSTRACT

Edward Westermarck was deeply influenced by Darwin's theory of natural selection, and this influence is apparent in several of his attempts to provide explanations of human behaviour. His most famous contribution to more recent work in sociobiology and evolutionary psychology is his explanation of why humans avoid sex with their close kin. His hypothesis that humans come to avoid sex with peers raised in the same household became known as the Westermarck effect. It would be a mistake to think that his work on incest avoidance in humans is his only contribution to sociobiology and evolutionary psychology, but the Westermarck effect is certainly the most frequently debated and well remembered. It continues to be at the absolute centre of discussion in the modern version of evolutionary psychology. Alongside Darwin's work on emotions, Westermarck's work on incest was one of the first attempts to use Darwinian reasoning as a tool to understand human psychology.