Impairment of unconscious, but not conscious, gaze-triggered attention orienting in Asperger's disorder

Impairment of joint attention represents the core clinical features of pervasive developmental disorders (PDDs), including autism and Asperger's disorder. However, experimental studies reported intact gaze-triggered attentional orienting in PDD. Since all previous studies employed supraliminal presentation of gaze stimuli, we hypothesized that individuals with PDD may be impaired not in conscious but in unconscious gaze-triggered attention shift. We tested the hypothesis in a group of Asperger's disorder (N = 12) and age- and gender-matched controls (N = 13), using a cueing paradigm with supraliminal and subliminal presentation of gaze cues. Under supraliminal conditions, the gaze cueing effect was evident in both groups. Under subliminal conditions, the Asperger group, unlike the control group, did not show the gaze cueing effect. These results indicate the impairment of unconscious, but not conscious, joint attention in Asperger's disorder, which may underlie some clinical findings of social malfunction in PDD.