Development of Interactional Synchrony in High- and Low-Risk Infants During Mother Infant Face-to-Face Interactions

Background: Typically-developing infants, from the first days of life, engage preferentially with social aspects of their surrounding environment. Examples include both their ability to distinguish whether or not an adult is looking at them, as well as their preferential fixation, from at least 3 months of age, to the eyes of others. Many of these engagements are directed by the dynamic face-to-face interactions between infant and caregiver. In previous research, by 3 months of age, mothers are more easily able to elicit infant responses during face-to-face interactions. By 6-9 months of age, unsolicited infant responses become more frequent. These milestones indicate the development of the infant’s ability to initiate face-to-face interactions, social bidding, the first step in eliciting and maintaining a contingent social interaction. 

Objectives: This experiment is intended to test the hypothesis that changes in visual scanning by caregiver and infant during face-to-face interaction coincide with the development of infant social bidding. In addition, we aim to investigate how the visual scanning patterns of both participants indicate when infant social bidding is mastered and the steps leading to its development. 

Methods: Using eye-tracking technology, we compared the visual scanning of caregivers and infants enrolled in a longitudinal prospective study of infant siblings of children with autism spectrum disorder (ASD). Infants at high-risk for ASD had a full sibling with a confirmed diagnosis of ASD, whereas infants at low-risk had no siblings with, or family history of, ASD. Between ages 2 to 6 months, visual scanning was compared between the two groups during three conditions: watching a videotaped actress (condition 1), participating in face-to-face interaction with their caregiver (condition 2), and a pre-recorded, thus non-contingent, video of the infant’s caregiver recorded during a previous session (condition 3). Fixation data were used to divide each condition into periods of mutual and non-mutual gaze. In addition, these data were used to determine which participant initiated and broke each mutual gaze period. Propensity of each participant to look at the eyes, mouth, body, or object areas during periods of non-mutual gaze, as well as facial affect during mutual and non-mutual gaze were quantified. 

Results: Results indicate that low-risk infants show increased mutual gaze duration and decreased mouth fixation during contingent interaction with caregivers (condition 2) as compared with pre-recorded videos of actresses (condition 1).  Preliminary results also indicate that as low-risk infants get older, duration of mutual gaze decreases, while number of mutual/non-mutual cycles increases. However, our high-risk ASD sample indicates increased variability in looking patterns. 

Conclusions: Preliminary results suggest that changes in the visual scanning patterns of infants can be attributed to infant social learning. This experimental paradigm is likely to potentiate between-group differences relative to infants at-risk for autism, thus increasing the utility in detection of early deviations from the course of normal social development.