The purpose of this study was to trace the development of children's understanding of emotions between the ages of 4 and 12. Twenty-four children at each of five age groups (4, 6, 8, 10, and 12), equally divided by sex, served as subjects. Three groups of tasks were administered: (1) the recognition of facial expressions from photographs, (2) the identification of target emotions contextualized in stories, and (3) the elicitation during conversation of children's accounts of situations which provoked emotions in themselves and in adults. Particularly emphasized were the differences in responses between the various age groups. The results maintained the grounding of emotion in the appraisal of situations and indicated that the understanding of situation increased with the growth of experience in children. The study suggests that, if the development in children's understanding of emotion as an organized construct is to be investigated seriously, both their knowledge of situational factors and of internal psychological factors should be considered jointly to ascertain if and how these factors change with age and how they interact. (DST)