In the face of danger: specific viewing strategies for facial expressions of threat?

We employed a psychophysiological marker of directed attention (the visual scan path) to investigate visuocognitive processing of particular facial expressions in healthy individuals (N = 47). Visual scanpaths were recorded using video-oculography while subjects viewed digitised photographs of threat-related (fear, anger) and non threat (sad, happy, neutral) facial expressions. Hypotheses regarding the existence of a differential viewing strategy for threat-related facial expressions were based upon the adaptive significance of rapid detection and effective appraisal of social threat from conspecific face stimuli. When compared with each of the non threat faces, viewing strategies for expressions of anger and fear were characterised by increased distance between fixations (extended scanning), with more fixations, of longer duration, to feature areas of these faces. The extended scanning style suggests that threat-related faces evoke a "vigilant" style of scanning, whereby longer saccadic eye movements may reflect heightened autonomic responses to threat, while the increased foveal attention to feature areas of threat-related faces may facilitate cognitive appraisal of the personal significance and direction of impending threat. These results suggest the existence of distinct visuocognitive patterns for processing threat-related facial expressions, in response to the evolutionary advantage of detecting and appraising social threat.