LAUSR

Abstract The behavioral activation system (BAS), a putative neurobiological system guiding approach-related behavior and linked with increased risk for bipolar disorder, has long been associated with positive affect (PA). However, PA is multi-faceted, and little is known about BAS sensitivity's relationship to lower level PA facets, nor whether any such associations manifest prospectively in daily life or interact with environmental rewards. The present study mapped the relationship between BAS sensitivity and distinct facets of PA both cross-sectionally and across 7 days. Young adults (N = 265) completed measures of BAS sensitivity and affect at baseline, followed by one week of thrice daily surveys of daily affect and reward engagement. Exploratory factory analysis confirmed the multidimensional nature of PA (i.e., Serenity, Joviality, Attentiveness, Self-Assurance). Heightened BAS sensitivity predicted greater daily levels of Joviality and Self-Assurance, but not Serenity. BAS did not significantly moderate daily reactions to rewarding events, although there were trends in this direction. Findings support a multi-faceted structure of PA and suggest that only certain facets of PA may be related to BAS hypersensitivity. Findings point to potential clinical implications for discriminating among different types of positive affect.