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.