Atypical recognition of dynamic changes in facial expressions in autism spectrum disorders

Previous studies have suggested that the processing of dynamic facial expressions is impaired in autism spectrum disorders (ASD). However, the specific component that is impaired in the processing of dynamic facial expressions has not been identified. We investigated the recognition of dynamic changes in facial expressions among individuals with ASD and age- and sex-matched typically developing controls. Morphing animations of facial expressions of six emotions were presented at four different changing speeds, and participants rated the naturalness of the expression changes. The correspondence between reduced speeds and decreased naturalness ratings was weaker in the ASD than in the control group. These results suggest that the atypical visual analysis of dynamic changes in facial expressions underlies the impairment in real-life social interaction among individuals with ASD.