ABSTRACT
The field of social psychology has generated an impressive array of empirical studies, yet it suffers from a lack of a strong connection to disciplines like anthropology, sociology, and economics. In the social sciences more generally, one of the most difficult problems is linking individual-level phenomena like social learning with societal scale ones like social institutions. Evolutionary theory begins with models of individual behavior and then aggregates across individuals and across time to deduce the long-run population-level outcomes of an evolving system. In the case of humans, we have to keep track of two systems of inheritance, genes and culture. Individuals inherit genes and culture by sampling from the population of which they are a part. Concerning culture, the sampling process differs both in the identity and number of people sampled and in the biasing decision rules people can use to acquire culture. As people use cultural or genetic variants they have inherited, they may prove varyingly successful in surviving and transmitting variants to other individuals. These mostly minor changes at the individual level modify the population that is available for imitation, teaching, and genetic reproduction in the next time period. Minor changes at the individual level, if reasonably consistent across individuals and over time, have big effects at the population level.
Evolutionary theory is one of the important unifying forces in biology, and, when proper attention is paid to our peculiar cultural system of inheritance, it will play a similar role in the human sciences.
