Eye-Tracking Restricted Behaviors and Interests in Autism

Background: Although eye-tracking studies of autism spectrum disorder (ASD) have primarily focused on the social domain, recent work is also using this technology to examine and quantify restricted behaviors and interests.

 Objectives:  This talk will present an overview of recent studies using eye-tracking to explore restricted behaviors and interests in ASD, as well as highlight some new findings from our group.

 Methods: Over a series of studies, our group has used eye-tracking to quantify the visual attention patterns of children with ASD during several passive viewing tasks of competing social and nonsocial stimuli. Nonsocial content includes commonplace items (e.g., furniture) as well as objects related to circumscribed interests (CI; e.g., trains), a diagnostic characteristic of ASD defined by an intense and interfering preoccupation within a narrow range of topics.

 Results: We have shown that school-age children with ASD explore fewer images within complex arrays than typically-developing (TD) children, while exhibiting greater perseverative and detail-oriented attention to the images they do view, particularly when those images depict CI objects (Sasson et al., 2008). These effects have been largely replicated with preschool children with ASD (Sasson et al., 2011), with differences in visual exploration increasing developmentally into adulthood (Elison et al., 2012). More recently, a simplified “paired preference” design demonstrated that CI objects disproportionately reduce attention to concurrently presented social information in very young children with ASD (Sasson & Touchstone, 2014), suggesting that certain object categories may unduly capture attention in children with ASD from a very early age and perhaps “crowd out” the social input associated with normative development. Data from a subsequent paired preference design has just been analyzed, and demonstrate that related effects extend into adolescence. Compared to the TD group (n=32; M age=166.6mos), the ASD group (n=33; M age=168.3mos) spent a greater proportion of their fixation time on objects (F(1,63)=15.4, p=.005)  and less on faces (F(1,63)=20.1, p=.001), and demonstrated an orienting advantage for prioritizing objects (F(1,63)=3.65, p=.026). Further, the presence of CI objects delayed orienting to faces for the ASD group but not the TD group (diagnosis X object type interaction; F(1,63)=4.3, p=.042). 

Conclusions: Collectively, these studies suggest early-emerging imbalances in social and non-social attention in ASD that extend at least through adolescence. Most notably, we have now replicated across several studies using various tasks and samples that social prioritization in ASD is modulated by the salience of competing nonsocial stimuli. This finding suggests that the effect of CI is not only pertinent to the study of repetitive behaviors, but may influence the social domain as well. Increased salience of nonsocial aspects of the environment, coupled with evidence of an over-focused attentional style, may restrict the visual experiences associated with normative social development in ASD, and over time may reinforce both the repetitive and social behaviors associated with the disorder. In this sense, the social motivation theory of autism appears narrowly correct (i.e., social stimuli hold reduced reward value in ASD) but may not account entirely for the broader pattern of motivational differences that characterize autism.