Self-esteem reactions to social interactions: evidence for sociometer mechanisms across days, people, and nations.

People have a fundamental need to belong that motivates them to seek out social interactions with close others (Baumeister & Leary, 1995). Leary and Baumeister's (2000) sociometer theory (SMT) poses that people who succeed in satisfying this need have higher self-esteem (SE). This prediction was tested across three hierarchical levels: intraindividual, interindividual, and international. Indicators of social interaction quantity, quality, and the interaction between quality and quantity were collected for relationships with friends, family members, and romantic partners. On the intraindividual level, relationship quality and the interaction between quantity and quality emerged as significant predictors of daily fluctuations in SE. Cross-lagged analyses indicated that this association is at least partly due to the effect of social inclusion on changes in SE. On an interindividual level, people who generally reported higher quality relationships also had higher levels of trait SE. On an international level, countries whose inhabitants regularly interact with friends were characterized by higher nationwide SE levels than countries without such practices, even when happiness, individualism, gross domestic product, and neuroticism were controlled.