Categorical perception of facial expressions in individuals with non-clinical social anxiety

Abstract

Background and objectivesAccording to the well-established categorical perception (CP) of facial expressions, we decode complicated expression signals into simplified categories to facilitate expression processing. Expression processing deficits have been widely described in social anxiety (SA), but it remains to be investigated whether CP of expressions are affected by SA. The present study examined whether individuals with SA had an interpretation bias when processing ambiguous expressions and whether the sensitivity of their CP was affected by their SA. MethodsSixty-four participants (high SA, 30; low SA, 34) were selected from 658 undergraduates using the Interaction Anxiousness Scale (IAS). With the CP paradigm, specifically with the analysis method of the logistic function model, we derived the categorical boundaries (reflecting interpretation bias) and slopes (reflecting sensitivity of CP) of both high- and low-SA groups while recognizing angry-fearful, happy-angry, and happy-fearful expression continua. ResultsBased on a comparison of the categorical boundaries and slopes between the high- and low-SA groups, the results showed that the categorical boundaries between the two groups were not different for any of the three continua, which means that the SA does not affect the interpretation bias for any of the three continua. The slopes for the high-SA group were flatter than those for the low-SA group for both the angry-fearful and happy-angry continua, indicating that the high-SA group is insensitive to the subtle changes that occur from angry to fearful faces and from happy to angry faces. LimitationsSince participants were selected from a sample of undergraduates based on their IAS scores, the results cannot be directly generalized to individuals with clinical SA disorder. ConclusionsThe study indicates that SA does not affect interpretation biases in the processing of anger, fear, and happiness, but does modulate the sensitivity of individuals’ CP when anger appears. High-SA individuals perceive angry expressions in a less categorical manner than the low-SA group, but no such difference was found in the perception of happy or fearful expressions.