How Culture Drove Human Evolution

Humans are a highly ecologically successful species. Long before the origins of agriculture, our species had spread from the frozen tundra of Siberia to the arid deserts of Australia. The secret of our success lay neither in the intelligence of individuals nor in an array of local genetic adaptations. Instead, unlike other species, humans are entirely dependent on large bodies of culturally-transmitted information that accumulate over generations in ways that build complex non-genetic adaptations to local environmental challenges. Drawing on evolutionary modeling, cross-cultural and cross-species comparisons, laboratory experiments on social learning, and quantitative ethnographic work in small-scale societies, I argue that our species’ long reliance on this second system of inheritance, and its ever accumulating and complex adaptive products, has driven the expansion of human brains while shaping our cognitive abilities, manual dexterity, status psychology, gut size, and social inclinations. More broadly, this research program suggests that understanding human evolution requires considering the interaction between genetic and cultural inheritance systems.