Social complexity and the early social environment affect visual social attention to faces.

Diminished attention to socially relevant information appears to be an early emerging risk factor associated with autism spectrum disorders (ASD). However, inconsistencies across studies suggest that atypicalities in visual social attention in infants at high-risk for ASD during the first postnatal year may be subtle and more apparent under certain contexts. Here we explore factors that may moderate developmental trajectories in attention to faces, including the social complexity of the dynamic visual stimuli used to measure visual social attention and the early social environment of the infant as indexed by parental affectedness of ASD-related traits. Across infants at both high (HR) and low risk for ASD, attention to faces increased during the first postnatal year, with overall greater attention being allocated to schematic faces in the simpler video stimulus. Moreover, greater parental affectedness of ASD-related traits was associated with reduced developmental gains in attention to faces. For HR infants, greater attention to faces was positively associated with social communicative competence, including better joint attention skills and lower social impairments. Altogether, our findings highlight the importance of considering developmental level when selecting stimuli to longitudinally examine visual social attention, and the clinical relevance of including measures of infant's social environment in understanding early markers of ASD risk. Autism Res 2019, 12: 445-457 © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Attention to faces is an important means for infants to learn about the social world. The complexity of the social scene and an infant's early social environment both affect the amount of time infants at high- and low-risk for ASD look at faces during the first postnatal year. For infants at high-risk for ASD, greater attention to faces was associated with better social skills. Understanding an infant's social environment may have a positive impact on social communicative development.