The Evolution of Cultural Evolution
Richard McElreath, University of California, Davis
Two unusual facts about the human species are that (1) we acquire important portions of our behavior and beliefs by imitation and other forms of social learning---sometimes called "culture"---and (2) we cooperate in and engage in self-sacrifice for very large groups of unrelated individuals. In every society, most food production is only possible with highly-specialized knowledge and technology that no individual could invent in his or her own lifetime. Instead, it takes many human generations to make the skills and tools that every human uses. While some plausible socially-transmitted traditions have been found in other primates, their importance in daily subsistence and survival is much less than in humans. Likewise, in nearly every human society, people cooperate in much larger groups than do other primates. In addition, these groups comprise very weakly related individuals, and therefore, according to a body of evolutionary theory that has been quite successful at explaining altruism in other animals, should not evolve. The evolutionary origins of these two traits, culture and large-scale cooperation with non-kin, are uncertain. Yet a convergence of data and theory from anthropology, economics, and the natural sciences suggests how culture and large-scale altruism might have evolved and function in our species.