Smiling in the face of adversity: the interpersonal and intrapersonal functions of smiling.

This study examined hypothesized interpersonal and intrapersonal functions of smiling in positive and negative affective contexts. Smiles were measured during a lab-based monologue task following either happy or sad emotion-evoking films. Psychological adjustment and social integration were measured longitudinally using data obtained in years prior to and after the experimental task. Duchenne (genuine) smiles predicted better long-term adjustment and this effect was mediated independently by both social integration and undoing of negative emotion during the monologue. These effects were observed only in the negative affective context. Non-Duchenne smiles were not related to psychological adjustment. Neither Duchenne nor non-Duchenne smiles during the monologue task were related to personality variables assessed in this study.