The Coevolution of Genes, Innovation, and Culture in Human Evolution

Abstract

Much adaptive human behavior is much too complex to be invented by any single individual in his lifetime. Such complex behavior can be learned and maintained in human populations, however, because our species possesses evolved psychological abilities for acquiring and modifying complex behavior and knowledge. One puzzle surrounding the origin of human behavior, with its strong reliance on socially transmitted knowledge, is how natural selection can favor costly abilities for complex social learning before the existence of complex behavior to be learned. The finding of special-purpose social learning abilities in other apes has only sharpened this puzzle – if other apes are good at imitation, is the key difference between ourselves and chimpanzees instead rates of innovation? In this chapter, I explore this puzzle by considering the simultaneous coevolution of both social learning ability and individual innovation. When one allows both innovation and the accuracy of social learning to evolve independently of one another, natural selection can favor increased investment in social learning, but only if it first favors increased innovation. However, once social learning evolves to high accuracy, high innovation rates are no longer needed, and natural selection favors reduced investment in innovation. Thus, the debate about whether innovation or imitation defines the gap between humans and other apes may be misstated. Instead, the emergence of human culture may have required the coevolution of both kinds of learning.