Children with Autism Spectrum Disorder Prefer Looking at Repetitive Movements in a Preferential Looking Paradigm

Background: Individuals with ASD have been reported to show abnormal visual attention, including reduced attention at others’ faces and eyes (e.g., Frazier et al., 2017; Tanaka & Sung, 2016), and abnormal visual preference for non-social objects (e.g., Chawarska et al., 2013; Sasson & Touchstone, 2014). Unlike the abnormal attention related to social stimuli, the visual abnormality related to the restricted interests and the repetitive behaviors has attracted limited research attention. The assessment of repetitive behavior in ASDs was mostly based on subjective reports from parents or clinical observations (e.g., Autism Diagnostic Observation Schedule; Lord et al., 2000). Several studies have examined the repetitive behaviors related stimuli (RBRS) in ASD by displaying RBRS and social stimuli simultaneously (Pierce et al., 2011; Pierce et al., 2016; Sasson & Touchstone, 2014). Considering the limitation of the interference of social stimuli in previous studies, the present study aimed to examined the visual preference for the repetitive movements in young children with ASD.

Objectives: The present study was designed to examine the visual preference for the repetitive movements in young children with ASD.

Methods: Twenty young children with ASD (2.74 - 5.24 years old) and 20 IQ- and age-matched typically-developing (TD) children were presented simultaneously with repetitive movements (e.g., a butterfly flying in a circle route) and random movements (e.g., the same butterfly flying in a random route). A Tobii Pro X3-120 eye tracker recorded children’s eye movements simultaneously. Two areas of interest (AOIs) were defined for the two different moving patterns in each trial: the repetitive movement AOI and the random movement AOI. We analyzed total looking time on the repetitive and the random movements for each trial, and computed the average proportional looking time on the repetitive AOI against the total looking time on both the repetitive and the random AOIs, defined as dynamic repetitive preference index (RPI). we also conducted a temporal course analysis of the RPI by dividing each trial into three phases (early, middle, and late phases, each phase lasting for approximately 31 seconds). A well above chance level (50%) RPI represents a looking preference for the repetitive movements over the random movements. Parent reports were accessed using Repetitive Behavior Scale-Revised (RBS-R; Bodfish et al., 2000).

Results: As shown in Figure 1 and Figure 2, We found that: (1) children with ASD spent significantly more time fixating on the repetitive movements than the random movements, whereas TD children showed no preference for either type of movements; (2) temporal course analysis further revealed that, this preference for the repetitive movements in ASD emerged as early as the first 30 seconds; (3) children’s preference for repetitive movements was correlated with the severity of repetitive behaviors based on parent reports, but not with their ages and cognitive functions.

Conclusions: Our findings not only reveal the gaze abnormality of ASD beyond the previously reported atypical social attention, but also show a promise in using the preferential looking as a potential indicator for the repetitive behaviors and aiding early screening of ASD in future investigations.