This document presents five studies testing the sociometer hypothesis of self-esteem, which posits that self-esteem functions as a monitor of social inclusion and exclusion. The findings indicate that self-esteem is closely related to experiences of social acceptance or rejection, and that fluctuations in self-esteem correspond to individuals' perceptions of their inclusionary status within social groups. Overall, the research provides support for the idea that self-esteem directly reflects personal social relations rather than being an inherent need.