Spatiotemporal Eye Movement Dynamics Reveal Altered Face Prioritization in Early Visual Processing Among Autistic Children.

Background: Reduced social attention - looking at faces - is one of the most common manifestations of social difficulty in autism central to social development. Although reduced social attention is well-characterized in autism, qualitative differences in how social attention unfolds across time remains unknown.

Methods: We used a computational modeling (i.e., hidden Markov modeling) approach to assess and compare the spatiotemporal dynamics of social attention in a large, well-characterized sample of autistic (n = 280) and neurotypical (n = 120) children (ages 6-11) that completed three social eye-tracking assays across three longitudinal time points (Baseline, 6 weeks, 24 weeks).

Results: Our analysis supported the existence of two common eye movement patterns that emerged across three ET assays. A focused pattern was characterized by small face regions of interest, which had high probability of capturing fixations early in visual processing. In contrast, an exploratory pattern was characterized by larger face regions of interest, with lower initial probability of fixation, and more non-social regions of interest. In the context of social perception, autistic children showed significantly more exploratory eye movement patterns than neurotypical children across all social perception assays and all three longitudinal time points. Eye movement patterns were associated with clinical features of autism, including adaptive function, face recognition, and autism symptom severity.

Conclusions: Decreased likelihood of precisely looking to faces early in social visual processing may be an important feature of autism that was associated with autism-related symptomology and may reflect less visual sensitivity to face information.