Attentional Abnormalities in Young Children with ASD: Limited Capture by Socially Relevant Stimuli

Background:  

Young children with Autism Spectrum Disorders (ASD) exhibit atypical scanning patterns and poor face recognition.  It is not clear, however, if face processing deficits are also expressed at a basic attentional level, as manifested through decreased attention capture by faces.  When typically developing children and adults are engaged in examining a face, shifting visual attention away from the face is more effortful than shifting away from other classes of stimuli.  This increased attention capture by faces is thought to reflect deeper level obligatory processing triggered by these highly socially and biologically relevant stimuli. 

Objectives:

To examine if attention capture by faces is disrupted in the early developmental stages of ASD.

Methods:

Children with ASD (M_age=32 months, N=42) were compared with developmentally delayed (M_age=29 months, N=31) and  typically developing (M_age=29 months, N=46) children.   Attention capture was tested using a variation of the overlap cued attention task in which participants were required to disengage visual attention from face or non-face central stimuli and make a reactive saccade to a peripheral target.  Main outcome measure consisted of saccadic reaction time (SRT).  The experimental protocol was approved by the Human Investigations Committee and an informed written consent was obtained from all parents prior to the testing. 

Results:

Disengaging from a face as measured by SRT was more difficult for developmentally delayed (p < .001) and typically developing children (p < .021) than for those with ASD, suggesting that their attention is not captured by faces to the same extent as in their comparison groups.  This effect appeared specific to faces and was not observed in response to non-face stimuli, where SRT was comparable in all three groups.

Conclusions:

The results suggest that face processing difficulties in children with ASD involve disruption of an elementary attentional mechanism that typically supports obligatory processing of face stimuli.  Findings are discussed in the context of a developmental model of face processing in ASD.