The Hidden Costs of Social-Evaluative Threat: A Default Network Interference Hypothesis

Social-evaluative threat (SET) can impair cognitive performance, especially for individuals high in social anxiety. This impairment is likely related in part to a diversion of task-focused attention toward internal, self-focused thoughts. Socially anxious people sometimes show performance deficits even in the absence of explicit social evaluation, suggesting that minimally evaluative environments may heighten self-focus in socially anxious individuals. However, little is known about the degree to which subtler variations in social context interact with social anxiety to affect cognitive performance and, further, what neural mechanisms mediate these effects. To address this, this dissertation tests the default network interference hypothesis of SET—that SET leads to poorer cognitive performance, exacerbated by social anxiety, due to difficulty suppressing activity in a collection of brain regions related to self-focus called the default network.

Study 1 (n=61) tested a novel social context manipulation to determine whether performance on the n-back working memory task was affected by social context and whether trait levels of fear of negative evaluation (FNE) and task difficulty interacted with this. Results indicated that individuals higher in FNE showed interference via longer RTs during harder 3-back trials when under SET compared to non-SET conditions. Interestingly, SET resulted in improved accuracy during easier 2-back trials. This suggests that although ongoing SET may improve task effectiveness, efficiency is reduced, especially in socially anxious individuals during high task difficulty.

In Study 2, participants (n=101) underwent the social context manipulation from Study 1 during concurrent recording of EEG in order to test the default network interference hypothesis of SET. EEG power in the theta band (4-8 Hz) at frontal midline sites was used as a marker of default network suppression. We found evidence for default network interference, as frontal theta, which led to better accuracy, was reduced during SET. In addition, individuals high in FNE showed less improvement in accuracy as a result of higher frontal theta, suggesting less efficient neural processing. Threat again predicted overall better accuracy despite predicting decreased frontal theta, indicating competitive mediation. Participants reported exerting more effort during SET, which led to improved accuracy, suggesting that individuals may have compensated for lower frontal theta during SET by increasing cognitive effort. Together, these studies elucidate a potential neural mechanism for the cognitive effects of social-evaluative threat, suggest methodological decisions to consider in social anxiety research, and help explain cognitive impairments seen as a result of SET and social anxiety.