This report discusses three studies of 2- to 5-year-old children's interpretations of facial expressions in terms of (1) the structure of the emotional domain and (2) prototypic example, overlap, and range of emotion categories. In the first study, 78 children were asked to make similarity judgments about 10 photographed facial expressions by sorting the photographs into two, three, and five piles. Results suggested that children as young as 2 years structure the emotional domain in roughly the same way as older children and adults and that they may perceive emotion in terms of pleasure and arousal. In the second study, 60 pre-schoolers at each of four age levels and a comparison group of 60 adults were asked to tell which of two facial expressions corresponded to an emotion label. In general, children's choices indicated that their categories of emotion are broader than adults', although children and adults usually shared the same prototype. In the last study, 48 children and 20 adults were asked to tell whether or not each of the 10 facial expressions corresponded to an emotion label. Results indicated that, for each emotion word, several faces apply; in addition, each face was seen as an example of several emotions. In both cases, the range narrowed with age. It was concluded that it is more useful to describe carefully children's behavior in interpreting facial expressions than to assess children's responses against an adult norm. (Author/CB)