A growing body of research suggests that pride and shame are associated with distinct, cross-culturally recognised nonverbal expressions, which are spontaneously displayed in situations of success and failure, respectively. Here, we review these findings, then offer a theoretical account of the adaptive benefits of these displays. We argue that both pride and shame expressions function as social signals that benefit both observers and expressers. Specifically, pride displays function to signal high status, which benefits displayers by according them deference from others, and benefits observers by affording them valuable information about social-learning opportunities. Shame displays function to appease others after a social transgression, which benefits displayers by allowing them to avoid punishment and negative appraisals, and observers by easing their identification of committed group members and followers.