Effects of Contingency On Social Visual Engagement in Typically-Developing Infants

Background: Typically-developing babies, from within the first days of life, engage preferentially with social aspects of the surrounding environment. Examples include both their ability to distinguish adults looking at them from those who are not, as well as their preferential fixation, from at least 3 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 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. 

Methods: We compared visual scanning for 22 typically-developing 2- to 6-month-old infants in two conditions: watching videotaped actresses (Condition 1) and live interaction with mothers (Condition 2).  We disambiguated the factors impacting on 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: Results show that typically-developing infants significantly increase their fixation on eyes during contingent interaction with mothers (Condition 2) as compared with their responses to pre-recorded videos of actresses (Condition 1).  Additionally, children increase their fixation on mouths when viewing non-contingent, pre-recorded clips of their own mothers (Condition 3).

Conclusions: Preliminary results suggest that live interaction increases eye-fixation in typically-developing babies. This experimental paradigm is likely to potentiate between-group differences relative to infants at-risk for autism, thus increasing its utility in the detection of early deviations from the course of normative social visual engagement.