Indexed on: 07 Mar '12Published on: 07 Mar '12Published in: Emotion (Washington, D.C.)
Threatening faces involuntarily grab attention in socially anxious individuals. It is unclear, however, whether attention capture is at the expense of concurrent visual processing. The current study examined the perceptual cost effects of viewing fear-relevant stimuli (threatening faces) relative to a concurrent change-detection task. Steady-state visual evoked potentials (ssVEPs) were used to separate the neural response to 2 fully overlapping types of stimuli flickering at different frequencies: Task-irrelevant facial expressions (angry, neutral, happy) were overlaid with a task-relevant Gabor patch stream, which required a response to rare phase reversals. Groups of 17 high and 17 low socially anxious observers were recruited through online prescreening of 849 students. A prominent competition effect of threatening faces was observed solely in elevated social anxiety: When an angry face, relative to a neutral or happy face, served as a distractor, heightened ssVEP amplitudes were seen at the tagging frequency of that facial expression. Simultaneously, the ssVEP evoked by the task-relevant Gabor grating was reliably diminished compared with conditions with neutral or happy distractor faces. Thus, threatening faces capture and hold low-level perceptual resources in viewers symptomatic for social anxiety at the cost of a concurrent primary task. It is important to note that this competition in lower tier visual cortex was maintained throughout the viewing period and was unaccompanied by competition effects on behavioral performance.