Culture is a central but elusive concept in the social sciences, and so are its effects. We leverage a natural experiment in the oldest university in East Africa — a cradle of economic and political elites — where students are randomly assigned to live in halls of residence that have maintained distinct student cultures since the 1970s. A broad consensus at the university characterizes certain halls as sociable and activist, and others as academically minded and respectful. Using an original survey of current students and behavioral games, we find that hall cultures influence a mixture of individual and interpersonal outcomes, specifically students' time preferences, identity, and interpersonal trust and generosity. However, they do not influence students' academic performance, social habits, or political preferences. An alumni survey suggests that cultural influence wanes but some effects endure, notably participation in activism. Our results provide novel evidence that cultural influence extends to several social domains.