Social norms have played a key role in the evolution of human cooperation, serving to stabilize prosocial and egalitarian behavior despite the self-serving motives of individuals. Young children’s behavior mostly conforms to social norms, as they follow adult behavioral directives and instructions. But it turns out that even preschool children also actively enforce social norms on others, often using generic normative language to do so. This behavior is not easily explained by individualistic motives; it is more likely a result of (...) children’s growing identification with their cultural group, which leads to prosocial motives for preserving its ways of doing things. (shrink)