Intention, act, and outcome in behavioral prediction and moral judgment

72 children at 3, 4, and 5 years of age and 24 undergraduates were required to use information about intention under a normal causal system or a noncanonical one (e.g., hitting causes pleasure) to predict an agent's behavior. Additionally, they were asked to integrate intentions, acts, and outcomes to judge an act's acceptability and assign punishment. 3-year-olds performed poorly on behavioral prediction in the noncanonical condition. Most participants at all ages made categorical judgments of act acceptability based solely on outcome, although quantitative ratings reflected an age-related increase in sensitivity to intention information. When assigning punishment, many 3-year-olds used a simple intention or outcome rule, whereas older participants were more likely to use a conjunction rule (if outcome is negative and intention is negative then punish). Together, the results reveal both an early understanding of harm and changes in the complexity of the rules that children use to predict behavior and integrate information.