Proceedings of the Annual Meeting of the Cognitive Science Society

Not every prosocial act is equally praiseworthy. As adults, we tend to evaluate helpers depending on others’ needs; helping someone with a hard task may be more burdensome but also more prosocial than helping someone with an easy task. Despite growing evidence that infants are sensitive to the costs of others’ actions, whether such representations inform their evaluation of prosocial acts remains an open question. Here, we ask whether 16-month-olds’ preference between two helpers is sensitive to task difficulty. Infants preferentially reached for (Exp. 1), and looked at (Exp. 2), an agent who helped someone facing a high-cost task over an agent who helped someone facing a low-cost task. Such preference disappeared when the agents completed the same tasks in a self-serving context. These results suggest that infants use action cost not only to predict and explain others’ behaviors but also to evaluate others in prosocial contexts.