Mothers' tone of voice depends on the nature of infants' transgressions.

Emotional vocal signals are important ways of communicating norms to young infants. The second year is a period of increase in various forms of child transgressions, but also a period when infants have limited linguistic abilities. Two studies investigated the hypothesis that mothers respond with different vocal emotional tones to 3 types of child transgressions: moral (harming others), prudential (harming oneself), and pragmatic (creating inconvenience, e.