Ara Norenzayan: University of British Columbia

The rise of large-scale cooperation and the spread of parochial-prosocial religions in the last 12 millennia are two longstanding puzzles, one of human psychology, and the other of cultural history. I present a theory, maintaining that these two developments were importantly linked and mutually energizing. It is grounded in the idea that although supernatural beliefs and practices originally arose as nonadaptive by-products of innate cognitive functions, particular cultural variants were then selected in a long-term, cultural evolutionary process. A suite of culturally evolved religious beliefs and practices characterized by increasingly potent, moralizing, supernatural agents, credible displays of faith, and other psychologically active elements conducive to social solidarity promoted large-scale cooperation with co-religionists, contributing to success in intergroup competition and conflict. In turn, prosocial religious beliefs and practices spread and aggregated as these successful groups expanded and outcompeted rival groups through high fertility rates, conversions, cultural imitation, and conquest. In doing so, these relentlessly expanding human populations have brought about the Anthropocene, dominating every ecological niche and gravely straining the planet’s entire ecosystem. Evidence for some of these hypotheses, alternative accounts, and intriguing open questions are discussed.