Studying the emergence of rituals in childhood provides insight into the complex dynamics of social group cognition. This talk will examine how children identify and acquire ritual to affiliate with social groups and preliminary work uncovering the relationship between ritual and cooperation in development. Insights within and across populations are drawn from diverse methodologies, including behavioral experiments, multivocal ethnography, and group paradigms. The results illuminate a deep-rooted proclivity towards in-group preference, suggesting rituals as pivotal mechanisms fostering group cohesion. I posit that humans are psychologically prepared to engage in ritual, serving as a means for in-group affiliation and inclusion.