Trajectories of Social Attention in Infants at High Risk for ASD
Objectives: The present study aimed to explore how trajectories of social attention in HRA could relate to individual differences in cognitive and language ability.
Methods: A Tobii eye-tracker assessed attention to faces at 6 and 18 months in low-risk controls (LRC) with no family history of ASD (n=25) and HRA (by virtue of an older sibling with ASD; n=36). HRA were further divided into two groups based on clinical judgment from the infant’s final lab visit at 24 months or older: high-risk ASD-negative (HRA−, n=25) and high-risk ASD-positive (HRA+, n=11). At both ages, infants saw images of their mother and a stranger side-by-side, and analyses focused on the first two presentations (10s each, sides counterbalanced). Difference scores were calculated between the 6 and 18 month visit for percent time on eyes (%Eyes) and mouths (%Mouths) as a function of total time on faces. The Mullen Scales of Early Learning (MSEL; Mullen, 1995) was used at 36 months to examine language through receptive language (RL) and expressive language (EL) scores and cognitive outcome through the Early Learning Composite score (ELC).
Results: Between 6 and 18 months, infants showed a decrease in %Eyes (M=−12.6%) and an increase in %Mouths (M=+10.8%). One-way ANOVAs revealed no group difference for changes in attention across age (ps>.48). For each group, correlations were run between trajectories of change in %Eyes and %Mouths between 6 and 18 months and MSEL RL, EL, and ELC scores at 36 months. In HRA−, positive associations were found between change in %Eyes and 36mo RL, EL, and ELC (rs>.45, ps<.05), and a negative association was found between change in %Mouths and 36mo EL (r=−.533, p=.016). For HRA+, negative associations were found between change in %Eyes and 36mo EL and ELC (rs<−.70, ps<.025), and a positive association was found between change in %Mouths and 36mo ELC (r=.768, p=.016; see Figures 1 and 2). No significant associations were found for LRC.
Conclusions: Although groups did not differ in trajectories of change in social attention between 6 and 18 months, individual differences in these trajectories were associated with different language and cognitive outcomes at 36 months, depending on group. For HRA−, increasing attention to eyes and decreasing attention to mouths predicted better language and cognitive skills, while HRA+ showed the opposite pattern, with increasing attention to mouths and decreasing attention to eyes predicting better outcomes. Future work will be needed to ask why changes in social attention that might be adaptive for HRA− might not be adaptive for HRA+, and vice versa.