Cooperation, norms, and gene-culture coevolution

This paper studies how a continuum of individuals interacting in a binary public goods game can secure cooperation through transmitting and enforcing norms. The evolutionary model consists of three distinct dimensions: behavior, norms, and approval preferences. In line with the indirect approach proposed by Güth and Yaari (1992), behavior results from utility maximization, while norms and approval preferences evolve over time. The underlying evolutionary processes differ concerning speed and nature. Whereas norms evolve at the cultural level through peer interactions and socialization, approval preferences are (at least partly) biologically inherited and transmitted from parents to their offspring. We find that if cultural and biological reproductive fitnesses are derived from material and social factors, then an interplay of social disapproval mechanisms gives rise to stable equilibria in which positive cooperation levels persist. Moreover, we find stable equilibria characterized by heterogeneous behavior and moral attitudes across individuals.