Developmental differences in the understanding of and reaction to others' inhibition of emotional expression.

In Study 1,160 individuals from kindergarten (kd), 3rd, 6th, 9th, and college grades were presented story protagonists who facially expressed or did not express sadness/fear when encountering events that likely caused (relevant-inhibitory cause) or did not cause (irrelevant cause) the inhibition of the expression of emotion. In Study 2, 108 kd, 3rd-, and 6th-grade children viewed peers engaging in real interactions similar to the stories. In both studies, kindergartners judged that relevant-inhibitory causes decreased a peer's emotions. Older individuals displayed an understanding of the inhibition of emotional expression by ascribing greater emotion to the peer under relevant-inhibitory than irrelevant causal conditions. In Study 2, age differences in children's search for social information and prosocial behavior paralleled judgments of emotion.