People are approaching me: biased ensemble perception of biological motion in social anxiety

Social anxiety disorder involves excessive fear of negative evaluation and threat-related perceptual biases, but little is known about how it shapes perception of biological motion at both individual and crowd levels. We explored whether social anxiety is related to biased approach judgments for single walkers and ensembles when depth is disambiguated. One hundred forty-seven Korean university students completed two tasks with three-dimensional point-light walkers containing perspective cues. In Task 1, participants judged whether a single walker with headings from 0° to 24° was approaching, yielding an individual detection threshold. In Task 2, they judged whether a crowd of 10 walkers (mixtures of 0° and threshold+6° headings) was, on average, approaching, yielding a point of subjective equality (PSE). Social anxiety was assessed with the Social Phobia Scale and Social Interaction Anxiety Scale. Depressive symptoms were included as a covariate. We found that individuals with high social anxiety exhibited lower thresholds and PSEs, indicating a stronger bias toward perceiving ambiguous movement as approaching. These preliminary findings are consistent with theoretical accounts of threat-related perceptual biases in social anxiety and point to potential contributions of both item-level and ensemble-level processes in dynamic social perception.