Previous research suggests that the ability to make fine-grained distinctions among emotions emerges gradually over development. However, such studies have looked primarily at children’s first-person responses to emotional expressions or at whether children can match emotion labels to emotional expressions. Relatively little work has looked at children’s ability to link emotional responses to their probable causes. Here we ask two, three, and four year-old children and adults to identify the causes of vocal expressions. We looked within a single valence and asked whether children could distinguish expressions elicited by exciting, delicious, adorable, funny, and sympathetic events. Our results suggest both an early emerging ability to distinguish within-valence emotions and rapid development; by four, children’s performance mirrored that of the adults. This suggests that very early in development, children have a rich representation of emotions that allows them to link distinct positively valenced emotional expressions to their probable causes.