Patterns of Visual Fixation during Moments of High Engagement in School-Age Children with and without Autism Spectrum Disorder

Background: Atypical perceptions of the social world are a hallmark feature of Autism Spectrum Disorder (ASD). When viewing social scenes, individuals with ASD spend less time looking at the eyes of others and more time looking at less socially relevant features, such as objects (Rice et al., 2012). This atypical pattern of visual attention suggests that individuals with ASD experience the world in profoundly different ways compared to their typically developing (TD) peers. For greater insight into the subjective experience of individuals with ASD, this study examines not only where children with ASD look when viewing social scenes, but also how engaged they are with what they are looking at. Viewer engagement is quantified by measuring patterns of eye-blink inhibition, a novel method that capitalizes on the fact that blinking temporarily interrupts incoming visual information. Because blinking interrupts visual information, people unconsciously adjust the timing of their blinks to minimize the likelihood of missing critical information. Probabilistically, people are least likely to blink when looking at what they perceive to be most important and most likely to blink during moments perceived to be least important. Thus, by measuring patterns of visual fixation and blinking we can examine where children with ASD look when they are highly engaged. 

Objectives: To investigate: (1) where children with and without ASD look when viewing naturalistic social scenes; and (2) whether looking patterns are modulated by engagement with scene content. 

Methods: Eye-tracking data were collected while 92 children with ASD (mean age=10.32(3.2) years; 28 female) and 44 age- and IQ-matched TD children (mean age=10(2.9) years; 15 female) watched age-appropriate movies. Permutation testing was used to identify periods of statistically significant blink inhibition (indicating moments when children were highly engaged) and statistically significant increased blinking (indicating moments when children were less engaged) for each group separately (Figure 1). Percentage of visual fixation time on eyes, mouth, body, and object regions were calculated for each child over: (1) the entire viewing session; (2) periods of high engagement; and (3) periods of less engagement.

Results: Multivariate ANOVAs showed that, over the entire viewing session, TD viewers fixated more on eyes and mouths compared to children with ASD, who instead looked more at objects and bodies (all p’s<0.0001). These group differences were also observed during periods of high engagement (all p’s< 0.05; Figure 2a). Finally, there was a significant interaction between diagnosis and level of engagement, with TD viewers looking more at mouths when highly engaged compared to when they were less engaged (p<0.05; Figure 2c). 

Conclusions: Results show that children with ASD and their TD peers perceive social stimuli in markedly different ways. TD viewers attend more to faces, while viewers with ASD attend more to objects. Critically, these differences become even more pronounced during periods when viewers were highly engaged with the stimuli. Ongoing analyses, examining between-group differences in the timing of when children are engaged and with what type of content, will further elucidate the subjective experience of individuals with ASD.