Interpretation bias in social anxiety as detected by event-related brain potentials

Little is known about psychophysiological correlates of interpretation bias in social anxiety. To address this issue, the authors measured event-related brain potentials (ERPs) in high and low socially anxious individuals during a task wherein ambiguous scenarios were resolved with either a positive or negative ending. Specifically, the authors examined modulations of the P600, an ERP that peaks approximately 600 ms following stimulus onset and indexes violations of expectancy. Low-anxious individuals were characterized by an increased P600 to negative in comparison with positive sentence endings, suggesting a positive interpretation bias. In contrast, the high-anxious group evidenced equivalent P600 magnitude for negative and positive sentence endings, suggesting a lack of positive interpretation bias. Similar, but less reliable results emerged in earlier time windows, that is, 200-500 ms poststimulus. Reaction time, occurring around 900 ms poststimulus, failed to show a reliable interpretation bias. Results suggest that ERPs can detect interpretation biases in social anxiety before the emission of behavioral responses.