Typical Levels of Eye-Region Fixation in Toddlers With Autism Spectrum Disorder Across Multiple Contexts

Abstract

Objective: Unusual eye contact is a common clinical feature in autism spectrum disorder (ASD), yet eye-tracking studies that quantify eye fixation report inconsistent results, possibly because of small samples, varied stimuli, and considerable heterogeneity of eye-region fixation even within typical development. Goals were to examine eye-region fixation levels in a large, very young cohort; the degree to which the presence of speech, hand gestures, and a geometric distractor influence eye-region fixation; and possible developmental changes across time.

Method: In experiment 1, 385 toddlers (143 with ASD, 242 without ASD, 11-47 months old) watched an actress engaging in child-directed speech with hand gestures against a plain background. Ninety-one toddlers participated approximately 8 months later. In experiment 2, another 231 toddlers (74 with ASD, 157 without ASD, 12-47 months old) watched the same video, but with embedded geometric distractors. Total fixation duration on facial and body regions (eg, eyes, hands) and geometric distractor regions (experiment 2 only) while the actress was speaking or silent, with or without gesturing, was examined, as were relations with clinical traits.

Results: Overall, across the 2 experiments and the 2 cross-sectional and longitudinal samples, eye-region fixation duration did not differ between toddlers with and without ASD, although fixation toward the face overall was decreased in toddlers with ASD. This decrease became more apparent with the presence of geometric distractors (experiment 2) as indexed by a geometric preference score, and this score was associated with autism severity.

Conclusion: Within the context of viewing child-friendly vignettes, decreased eye-region fixation does not reliably characterize toddlers with ASD. An index of competition between faces and external distractors might be a more robust measure.

Keywords: autism spectrum disorder; eye fixation; eye tracking; visual attention.