Effects of Contingency on Social Visual Engagement In Infants at High- and Low-Risk for ASD

Background: Typically-developing babies, from within the first days of life, engage preferentially with social aspects of the surrounding environment. Examples include their ability to distinguish adults looking at them from those who are not, as well as their preferential fixation, from at least 2 months of age, to the eyes of others. An important goal of current research in autism should be to capitalize on these and other early-emerging mechanisms of sociability in order to trace the earliest detectable deviations from normative development. This is a key step in identifying autism at the earliest possible time point.

Objectives: This experiment is intended to: (1) test the hypothesis that visual scanning behavior in typically-developing children will evidence discrimination between contingent and non-contingent interactions within the first six months of life and (2) to test whether this discrimination is evident in infants at high risk for developing autism.

Methods: Participants were enrolled in a longitudinal prospective study of infant siblings of children with autism spectrum disorders (ASD). Infants at high risk for ASD (HR-ASD) had a full sibling with confirmed diagnosis of ASD, whereas infants at low-risk (LR-TD) had no sibling with, or family history of, ASD. Between 2 and 6 months of age, we compared visual scanning for 10 HR-ASD siblings and 10 LR-TD infants in two conditions: watching videotaped actresses (Condition 1) and having live interactions with their own mothers (Condition 2).  We disambiguated the factors impacting differences between the two conditions (identity of adult [stranger/mother] versus presence of contingency [videotaped/live]) by adding a third condition: a pre-recorded, and hence non-contingent, video of the infant’s mother (Condition 3).  Eye-tracking data were collected during each of the three conditions. During collection of eye-tracking data, simultaneous video recordings captured the field-of-view of each participant (thus baby’s view showed mom, while mom’s view showed baby). Field-of-view recordings were coded into four regions (eyes, mouth, body and object). The eye-tracking data were then analyzed for time spent fixating on each of the four regions-of-interest.

Results: Preliminary results show that typically-developing infants show increased overall looking during contingent interaction with mothers (Condition 2) as compared with their responses to pre-recorded videos of actresses (Condition 1). Additionally, significant decreases in frequency of saccades, in offscreen fixations, and in fixations on body regions were noted across the two conditions. Strong positive trends were observed for increases in both eye- and mouth-looking. Additionally, mouth fixation increased when viewing non-contingent, pre-recorded clips of their own mothers (Condition 3). Preliminary results indicate increased variability in looking patterns for our HR-ASD sample.

Conclusions: Preliminary results suggest that typically-developing infants respond differentially to live interactions than pre-recorded videos. The significant decreases in saccades and offscreen fixations, in addition to increases in overall fixation time suggest that infants are more visually engaged during contingent interactions than when viewing pre-recorded movies. This experimental paradigm is likely to potentiate between-group differences relative to infants at-risk for ASD, thus increasing its utility in the detection of early deviations from the course of normative social visual engagement.