Results are presented of a cross-cultural study of differences in the reasons that children in the United States and Japan give for refraining from common types of aggression. Over 200 children, primarily fifth-graders, were interviewed individually. The study was an extension of previous research showing that children who voice a self-centered or hedonistic perspective based on punishment, as opposed to a perspective that focuses more on the needs of others, tend to be more disruptive and/or aggressive. In the current study, children in the United States, compared to children in Japan, were more likely to focus on the consequences of their behavior on themselves, not on others. Indeed, nearly all children in the United States (92%) gave at least one response that focused on punishment, and 79% gave a response that focused on either overt or relational retribution. In contrast, 90% of the children in Japan did "not" mention punishment and less than half (42%) mentioned one of the two types of retribution. Given previously reported differences in behavior between Japanese and American students, the present findings suggest that emphasizing rules and punishment--as widely practiced in American schools but not in Japanese schools--might not be the best strategy for promoting responsible behavior, especially over the long term. (Contains 2 tables and 3 footnotes.)