19216
Does Functional Gaze Following of Children with an Autism Spectrum Disorder Really Rely on Gaze Direction? an Eye-Tracking Study
Children with autism spectrum disorders (ASD) show abnormalities in functional gaze following. Although their gaze shifts towards attended objects are accurate, the duration of their first fixation at these objects is shorter suggesting weaker initial processing bias for attended objects (Falck-Yttter, Thorup, & Bölte, 2014). However, it is not clear whether they rely exclusively on other’s gaze direction or use other’s head direction to govern functional gaze following.
Objectives:
The experimental manipulation in this eye tracking study is whether or not an adult could see the objects by using an open and closed eyes paradigm (Brooks & Meltzoff, 2002) while objects were present or absent (Caron, Butler, & Brooks, 2001).
Methods:
Seven children with ASD (mean chronological age of 64 months; mean mental age of 36 months) and 7 mental age-matched typically developing younger children (TD) were involved in this study. Children saw video clips of an adult turning her head to the right or left in 2 different conditions (eyes open or closed) and with 2 different stimuli (with or without objects). This resulted in four different situations: open-eyes with object, open-eyes without object, closed-eyes with object, closed-eyes without object. Gaze was measured with a Tobii T120. The outcome parameters were the accuracy (amount of congruent gaze shifts minus amount of incongruent gaze shifts) and the duration of the first fixation to the attended target.
Results:
A three-way ANOVA (2groups*2conditions*2stimuli) revealed no significant effect for the accuracy (F=1.07; p=.32) whereas a significant effect was present for the duration of the first fixation to the attended target (F=11.64; p=.005). Post hoc testing showed that TD demonstrate a longer first fixation duration to the attended target in the open compared to the closed eyes conditions if objects were present (p=.04) in contrast to children with ASD (p=0.10).
Conclusions:
Consistent with Falck-Ytter et al. (2014), children with ASD followed the adult’s gaze in terms of accuracy as much as mental aged-matched younger children but showed an aberrant pattern of first fixation duration to the attended target. In line with findings of Brooks and Meltzoff (2002), gaze following of TD seems to be influenced by the open or closed status of the eyes, directing a higher initial object processing to the attended object when the eyes of the adult are open. In contrast, children with ASD showed no difference in initial object processing between open and closed eyes conditions. Findings suggest that gaze following of children with ASD may rely on the adult’s moving head and less on the status of the adult’s eyes. Since in naturalistic settings gaze shifts towards an object may indicate an upcoming goal-directed action with an object, an altered gaze following pattern and initial object processing can interfere with action understanding. To investigate action understanding in children with ASD the above mentioned aberrant gaze following pattern should be taken in account.