Emotion socialization begins within the family setting and extends outward as children transition into expanded social worlds. Children contribute to their socialization from the first years of life, so the dynamics between parents and children are reciprocal in nature. Because socialization influences are best inferred from patterns that unfold over time, longitudinal research can help to untangle these processes. Laboratory observations of emotion exchanges and discussions or experimental manipulations of environmental processes also provide valuable information about causal influences and direction of effects. Parents and children must be studied within the same research designs to understand emotion socialization.