Longitudinal Changes from 11 to 16 Months in Visual Attention to Dynamic Social Scene Among Infants at High and Low Genetic Risk for Autism

Background:    To understand the origins and emergence of autism symptomatology, research has investigated infants who have an older sibling with autism spectrum disorder (ASD) and are at heightened genetic risk for the disorder.  Findings by the Baby Siblings Research Consortium suggest that several developmental pathways to ASD are present from 18 to 36 months of age (Chawarska et al., 2014).  This study focused on early visual attention profiles that emerge from 11 to 16 months of age to further our understanding of developmental pathways that are indicative of genetic risk and/or ASD.  

Objectives:    The study examined developmental changes from 11 to 16 months in visual attention to a dynamic social scene among infants with (high-risk; HR) and without (low-risk; LR) an older sibling with ASD.  It was expected that HR infants would demonstrate less visual attention to the upper half of the face at 16 months than 11 months of age.  It was also expected that differences in visual attention would not emerge until 16 months, with HR 16-month-olds demonstrating less visual attention to the upper half of the face compared to LR 16-month-olds.  

Methods:   A prospective, longitudinal design was used to compare visual attention of HR infants (n=21) with LR infants (n=19) across early development (from 11 to 16 months).  Eye-tracking data were collected while infants viewed a dynamic social scene of an adult speaking and showing toys.  Regions of interest were drawn to quantify infants’ attention to scene elements (e.g., upper/lower facial regions, objects).  Infants participated at both 11 and 16 months.  These infants will be assessed at 24, 36, and/or 48 months and provided an outcome designation as typical, non-typical or ASD based on assessment tools including the Autism Diagnostic Observation Schedule-Generic (Lord et al., 1999).  Assessments are ongoing.        

Results:    Analyses indicate that when attending to the face, LR and HR infants demonstrated similar proportions of looking time to the upper half of the face at 11 months (M=.27, SD=.31; M=.26, SD=.29).  However, from 11 to 16 months, HR infants displayed a decrease in the proportion of looking time to the upper half of the face (M=.06, SD=.09), whereas LR infants remained consistent between the two age points (M=.30, SD=.28).  This is shown by the significant interaction (risk X age) in Figure 1 (F(1,32)=4.05, p=.05).

Conclusions:    A significant interaction between risk and age was found regarding infants’ distribution of attention within the face.  Importantly, HR infants demonstrated a decrease in the proportion of looking time to the upper half of the face from 11 to 16 months while LR infants’ attention remained stable.  This suggests that a decline in visual attention to the upper half of the face may be an early developmental pathway of the broader autism phenotype or ASD.  It broadly highlights the importance of identifying visual attention profiles of HR infants across early development since deficits may emerge after the first year of life.  Further analyses may elucidate the early developmental trajectories of HR infants’ visual attention based on later diagnostic outcome (ASD, non-typical).