Perception of facial expression and facial identity in subjects with social developmental disorders

Background: It has been hypothesized that the social dysfunction in social developmental disorders (SDDs), such as autism, Asperger disorder, and the socioemotional processing disorder, impairs the acquisition of normal face-processing skills. The authors investigated whether this purported perceptual deficit was generalized to both facial expression and facial identity or whether these different types of facial perception were dissociated in SDDs. Methods: They studied 26 adults with a variety of SDD diagnoses, assessing their ability to discriminate famous from anonymous faces, their perception of emotional expression from facial and nonfacial cues, and the relationship between these abilities. They also compared the performance of two defined subgroups of subjects with SDDs on expression analysis: one with normal and one with impaired recognition of facial identity. Results: While perception of facial expression was related to the perception of nonfacial expression, the perception of facial identity was not related to either facial or nonfacial expression. Likewise, subjects with SDDs with impaired facial identity processing perceived facial expression as well as those with normal facial identity processing. Conclusion: The processing of facial identity and that of facial expression are dissociable in social developmental disorders. Deficits in perceiving facial expression may be related to emotional processing more than face processing. Dissociations between the perception of facial identity and facial emotion are consistent with current cognitive models of face processing. The results argue against hypotheses that the social dysfunction in social developmental disorder causes a generalized failure to acquire face-processing skills.