DISTRIBUTION OF VISUAL ATTENTION WHEN COMPARING PAIRED FACES IN TYPICALLY DEVELOPING INFANTS AND INFANTS AT RISK OF DEVELOPING AUTISM

Infant eye tracking research has assessed the visual scanning of static and dynamic singularly presented faces. Yet, little is know about how infants visually compare paired faces. The current study characterizes the distribution of visual attention to paired faces for infants who where later diagnosed as being typically developing (TD), non-typically developing (NT), or having an autism spectrum disorder (ASD). The study sample was comprised of infant siblings of children with ASD (high-risk infants; HR) and infant siblings of typically developing children (low-risk infants; LR). Eye tracking data were collected at 11 months of age while all infants completed a visual paired comparison task. Stimuli were six face pairs, displayed for eight seconds each, created from twelve colored photographs of naturalistic female faces equivalent in facial expression. Participants were then asked to return at 24, 36, and/or 48 months of age for follow-up diagnostic assessment at which point they were categorized into the TD, NT, or ASD groups. When viewing paired faces, all three groups demonstrated a greater proportion of time looking to the bottom than the top half of the faces. Only the typically developing group looked longer to the right side of the face than the left; that is, demonstrated a left visual field (LVF) bias. The NT group spent significantly less time looking to the mouth regions than did the TD and ASD groups. With respect to paired face comparisons, there were no significant group differences in the overall number of congruent saccades. However, there were group differences in the proportion of congruent mouth-to-mouth saccades. Infants with ASD made the largest number of mouth-to-mouth comparisons, followed by the TD group, and the NT group. Group differences were also found in the proportion of scans that went from a non-internal facial feature of one pair member to a non-internal feature of the other pair member. Essentially, NT developing infants made more extraneous comparisons than did TD infants