Friend, Foe or I Don't Know: Electrophysiological Evidence of Enhanced Processing of Neutral Facial Expressions in Social Phobia
Jason S. Moser, Elizabeth Duval & Robert F. Simons
Department of Psychology, University of Delaware, Newark, DE, USA
Behavioral studies indicate that socially phobic individuals process faces
depicting prototypic angry expressions differently than normal controls.
Little evidence exists, however, concerning the processing of neutral (or
ambiguous) facial expressions in social phobia. Here, we extend these findings
by combining behavioral measures with event-related brain potentials (ERPs) to
investigate how socially phobic individuals differentially process emotional
and neutral faces. Specifically, we measured the P300, an ERP indexing
attentional allocation, while socially phobic and control participants viewed
pictures of neutral, angry and happy faces. Following ERP recording,
participants made judgments regarding each face on both valence and arousal
dimensions. Although there were no group differences on subjective
ratings of the faces, the P300 results indicated that controls, but not social
phobics, preferentially allocated attentional resources, as indexed by the
P300, to arousing (i.e., angry and happy) over neutral faces; P300s in the
social phobic group were identical for neutral, angry, and happy faces.
The current findings underscore the utility of ERPs in elucidating information
processing biases in social phobia as well as social phobics’ preferential bias
to treat neutral (or ambiguous) facial expressions as motivationally
significant. 
