Humans readily evaluate third-parties' prosocial and antisocial acts. Recent evidence reveals that this tendency emerges early in development-even preverbal infants selectively approach prosocial others and avoid antisocial ones. Rather than reflecting attraction toward or away from low-level characteristics of the displays or simple behavioral rules, infants are sensitive to characteristics of both the agents and recipients of prosocial and antisocial acts. Specifically, infants' preferences require that the recipients of positive and negative acts be social agents with clear unfulfilled goals, who have not previously harmed others. In addition, prosocial and antisocial agents must act intentionally, in the service of positive and negative goals. It is an open question whether these prosocial preferences reflect self-interested and/or moral concerns.
