Differences in startle reactivity during the perception of angry and fearful faces

Emotion researchers often categorize angry and fearful face stimuli as "negative" or "threatening". Perception of fear and anger, however, appears to be mediated by dissociable neural circuitries and often elicit distinguishable behavioral responses. The authors sought to elucidate whether viewing anger and fear expressions produce dissociable psychophysiological responses (i.e., the startle reflex). The results of two experiments using different facial stimulus sets (representing anger, fear, neutral, and happy) indicated that viewing anger was associated with a significantly heightened startle response (p < .05) relative to viewing fear, happy, and neutral. This finding suggests that while anger and fear faces convey messages of "threat", their priming effect on startle circuitry differs. Thus, angry expressions, representing viewer-directed threat with an unambiguous source (i.e., the expresser), may more effectively induce a motivational propensity to withdraw or escape. The source of threat is comparatively less clear for fearful faces. The differential effects of these two facial threat signals on the defensive motivational system adds to growing literature highlighting the importance of distinguishing between emotional stimuli of similar valence, along lines of meaning and functional impact.