Psychophysiological Responses to Direct Gaze in Children with Autism Spectrum Disorder

Background: It remains unclear why children with autism spectrum disorder (ASD) tend not to look at the eyes of other people. It has been suggested that direct gaze elicits an unusual degree of psychophysiological arousal that is felt uncomfortable by children with ASD. An alternative suggestion is that direct gaze is not socially motivating and, therefore, ASD children passively ignore it.

Objectives: The aims of the study were to investigate psychophysiological arousal and motivational brain responses to direct gaze in children with ASD. Skin conductance responses (SCRs), heart rate acceleration, and frontal alpha-band EEG activity were measured. Relative left- and right-sided asymmetries in the frontal alpha-band EEG activity have been associated with activation of the approach- and avoidance-related motivational brain systems, respectively.

Methods: The participants included 14 children with ASD and 15 gender-, age- and IQ-matched controls. The children ranged from 11 to 14 years old. The children viewed pictures of three familiar (parents and a teacher) and three unfamiliar faces with eyes shut and eyes open with a direct gaze. The stimuli were presented so that they first loomed toward the participants, creating an impression of an approaching person. The stimuli loomed for 3 seconds and then were static for 2 seconds. Skin conductance, electrocardiogram, and frontal EEG activity were recorded simultaneously.  

Results: The results showed that the ASD children had greater SCRs to direct gaze compared to shut eyes, whereas in the typically developing children there was no difference between the gaze conditions.  Typically developing children viewing faces with direct gaze showed greater relative left-sided, approach-related frontal EEG activity than when viewing faces with eyes shut. In children with ASD, the eye condition (direct gaze vs. shut eyes) did not have an effect on the frontal EEG activity.

Conclusions: The findings of the study showed that direct gaze elicits enhanced arousal in children with ASD. We could not, however, find evidence that heightened arousal to direct gaze is associated with avoidance tendency. Instead, it seems that children with ASD may lack the typical approach-related response to direct gaze. These findings are in line with assumptions that having eye contact with another person is not socially motivating for children with autism. These findings will be further discussed in relation to on-going studies in young children with autism.

The study was funded by Autism Speaks and the Academy of Finland.