This project aims to explore the idea that modern world religions are products of a long-term cultural evolutionary process, driven by competition among religions and societies, that has gradually assembled and integrated combinations of supernatural beliefs, rituals, devotions, and institutions that instill commitment, promote larger-scale cooperation, and sustain in-group harmony. Our team of anthropologists and psychologists will test a systematic series of hypothesis derived from this idea, through comparative controlled experiments and ethnography. This proposed cross cultural study, combined with other approaches from historical analyses and mathematical modelling, will forge a firmer understanding of how cultural evolutionary processes have shaped aspects of religions over time, and how those aspects in turn shape human sociality. Our goal is to conduct original, cutting-edge research that builds on existing funded resources in research infrastructure and collaborative networks. We expect a range of scholarly output to encompass a series of articles, books, and a synthetic volume. The project will also train a new breed of young researchers to integrate insights from ethnography and experiments to address these big questions.