Adolescents infer latent motives to build generalizable models of others’ behavior

Understanding and predicting others' behavior is a key developmental task in adolescence as social interactions become more complex. Because social situations rarely repeat exactly, accurate prediction requires generalization beyond past actions. We examined how adolescents ( n = 127; ages 10–20) predicted others' behavior across a series of economic games. Prediction accuracy improved with age. Computational modeling showed that this improvement was driven by an increasing tendency to infer unobservable motives underlying behavior (e.g., greed and risk aversion), with older adolescents more likely to infer multiple motives. In particular, inferring risk aversion became more common from early to mid-adolescence. These results suggest that adolescents increasingly build abstract, generalizable models of others' behavior, supporting flexible social reasoning in novel contexts.