It is assumed that our perceptual apparatus has been shaped by evolution. T
hus, stimuli and situations that have been dangerous to the survival of the
species should have some kind of priority in the way they are detected. le
arned or memorised.
Threatening facial expressions are a class of stimuli that have been studie
d in this context. In a series of visual search experiments with schematic
faces, subjects were asked to detect a deviant facial expression in a crowd
of nine faces presented on a computer screen. The results showed a general
attentional bias to detect threatening faces. Thus, an angry face among, e
.g., happy faces was detected faster and with fewer errors than a happy fac
e among angry faces. Furthermore, subjects with high and low scores on soci
al phobia were compared. In general, no differences were obtained in detect
ion time, but subjects in the group with high social anxiety did show more
errors.