Infants' recognition of social conventions

From early in life, humans expect members of the same social group to act like one another. What drives this expectation? Across two experiments, we investigated how 8- and 9-month-old infants’ (N = 100) expectations about shared behaviors align with accounts based on collective identities, ritualistic actions, or conventions. In Experiment 1, infants inferred that an action would generalize to a new group member only when they had previously seen more than one group member share that action, suggesting that multimember demonstration influences infants’ inductive reasoning. In Experiment 2, infants did generalize an action after observing it from just one group member, but only if they had observed that same action shared by two members of another group in a different social context. Together, these findings suggest that infants learn to recognize which actions are socially conventional and then readily generalize these actions even in new social contexts.