Positive peer interactions are critical for adolescent development and well-being. Showing little interest in interacting socially with peers and/or extracting little reward from positive peer interactions can be markers of social anhedonia, which impacts many youths, especially girls, with social anxiety and depressive disorders. Reduced interest or reward in peer interactions may contribute to social anxiety and depression in girls through effects on positive affect (PA), though associations between social anhedonia and momentary PA have yet to be tested. The present study used ecological momentary assessment to test such associations between real-world anticipatory social reward (i.e., interest in upcoming peer events), consummatory social reward (i.e., reward extracted from positive peer interactions), and momentary PA in a sample of 129 girls (aged 11-13 years) who were oversampled for high shy/fearful temperament, a risk factor for future social anxiety and depression. Girls reported higher PA following a more socially rewarding peer interaction, and higher PA on days they reported higher anticipatory social reward. Exploratory analyses showed that these associations were specific to PA
neither anticipatory nor consummatory social reward was associated with changes in negative affect. Findings may inform the development of clinical interventions that target social anhedonia to modify PA in youth with affective disorders.