Social scene perception in autism spectrum disorder: An eye-tracking and pupillometric study.

Typically, developing humans innately place subjective value on social information and orient attention to it. This can be shown through tracking of gaze patterns and pupil size, the latter of which taps into an individual's cognitive engagement and affective arousal. People with Autism Spectrum Disorder (ASD) present with atypical social, communicative and behavioral patterns, but underlying substrates of these behavioral differences remain unclear. Moreover, due to high comorbidity with other neurodevelopmental disorders, it is often difficult to distinguish which differences are distinctive to ASD. In this study, a group of 35 adolescents and young adults with neurodevelopmental disorders were tested to investigate the processing of social and non-social scenes in individuals who meet the diagnostic criteria for autism and those who do not. Eye tracking and pupillometry measures were collected while participants observed images of tightly controlled natural scenes with or without a human being. Contrary to individuals without autism diagnosis, participants with autism did not show greater pupillary response to images with a human. Participants with autism were slower to fixate on social elements in the social scenes, and this latency metric correlated with clinical measures of poor social functioning. The results confirm the clinical relevance of eye-tracking and pupillometric indices in the field of ASD. We discuss the clinical implications of the results and propose that analysis of changes in visual attention and physiological level to social stimuli might be an integral part of a neurodevelopmental assessment.