Study datasheet.

Early in ontogeny, children show a preference for prosocial others and for those with helpful intentions. Here, we investigate how children reason about prosocial actions when a selfish intention is revealed only after a prosocial behavior has benefitted them. 5-year-old children (N = 48) played a game with a puppet who acted prosocially by letting the child take a turn in a game. After the game, the puppet revealed either a selfish intention of getting a cookie for letting the child play (Undermining condition) or a prosocial intention of wanting the child to have fun (Prosocial condition). When given a chance to reciprocate a prosocial act, children shared less when the puppet had an Undermining versus a Prosocial intention. Children did not show any condition differences in their explicit social evaluations of the puppet, however. Our results indicate that an agent’s initially hidden selfish intention, revealed only after a prosocial action, negatively impacts a child’s willingness to later reciprocate with that agent.