Effect of social interaction negative affect on within-person mentalizing network connectivity

Understanding others’ intentions and emotions is supported by the mentalizing networkand helps people navigate the inherently complex dynamics of social interactions. However,work investigating the mentalizing network often relies on non-naturalistic methods, limiting ourunderstanding of individual differences most apparent within social interaction contexts. Wetook a naturalistic, multilevel approach to investigate relations between real-world affectiveexpressions, social anxiety symptoms and mentalizing network connectivity. Same genderidentityfriend pairs (40 participants; 62.5% Women; 87.5% White) engaged in a socialinteraction while videos from their individual visual perspectives were recorded. Participantswere later scanned while they watched clips of the interaction from their own (self run) and theirfriend’s (friend run) perspective. We found that expressed negative affect, not expressed positiveaffect, related to within-person variation in mentalizing network connectivity acrossperspectives. Further, participants higher in social anxiety symptoms showed more similarmentalizing network connectivity across perspectives when expressed negative affect was higherthan average, and particularly when friend negative affect expressions, rather than their ownnegative affect expressions, were higher. Mentalizing network connectivity may be responsive toshifts in negative affect during social interactions and friend negative affect expressions may beparticularly salient to people higher in social anxiety symptoms.