Abstract
The affective benefits of social contact depend on momentary social needs. Mismatch between desired and actual contact can result in social deprivation or oversatiation. We examined these dynamics in relation to affective wellbeing, considering genetic predispositions for loneliness, wellbeing, and depressive symptoms. A general-population sample of 1,086 adults (71% female, M(age) = 36.4) completed 7-day Ecological Momentary Assessments of affect and social contact eight times daily. Social mismatch was higher when alone (M = 3.67) than with others (M = 2.65). Dynamic Structural Equation Modelling showed higher negative affect (β = .18 and β = .04) and lower positive affect (β = -.19 and β = -.05) was related to more social mismatch concurrently and two hours later. Unexpectedly, social oversatiation was linked to reduced negative affect two hours later (β = -.03). Younger adults and those with a stronger genetic predisposition for wellbeing showed stronger effects of social mismatch on positive affect. The results highlights the complex relationship between social contact, needs, and affective wellbeing. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10902-025-00965-6.