Emotional Face Processing In Autism Spectrum Disorders: Evidence From China

Background:  

Autism spectrum disorders (ASDs) are neurodevelopmental disorders which are thought primarily to affect social interactions, while both behavioural and neuroimaging evidence indicate that individuals with ASD demonstrate marked abnormalities in the processing of faces and facial expressions. However, the literature on face processing in ASD presents quite a confusing picture. There is evidence that individuals with ASD tend to process the eye region of faces less effectively than typical individuals (e.g. Spezio et al., 2007), and that this difficulty may arise from a tendency not to look at the eye region of faces unless specifically instructed to (Dalton et al., 2005; Pehplrey et al., 2002). This tendency could, in turn, arise from the well known aversion to direct gaze in ASD.

Objectives:  

This study explores how individuals with ASD preferentially attend to video extracts containing human actors with different emotions and averted gaze. The proportion of gaze time spent fixating on different parts on faces, bodies and the background was investigated. This study was also designed to find out if individuals with ASD fail to orient toward the eyes or they actively avoid direct eye contact.

Methods:  

The reflexive eye-movements of 36 children and adults with ASD and 40 typically developing children and adults were recorded as they watched videos of fearful, sad, happy, and neutral faces and averted gaze. The proportion of time spent viewing eyes, mouths and other scene details was calculated, as was latency of the first fixation to eyes.

Results:  

While people with ASD preferentially attended to faces for less time than was typical, individuals with ASD atypical gaze behaviours extended across faces. People with ASD had more difficulties engaging visual attention and emotions from faces than typically developing people. Participants initially fixated either on the eyes or on the mouth. The ASD group showed a reduced preference for the eyes relative to the control group, primarily characterized by more frequent eye movements away from the eyes. When looking at people’s faces, children with ASD spent less time on the nose and mouth than typically developing group, but the fixation duration on eyes did not differ between the two groups. There are also differences on positive and negative facial emotions between two groups.

Conclusions:   

The eye-tracking data revealed influence of active avoidance of direct eye contact on atypical gaze in ASDs. Young children with ASD show less visual attention to facial expression and have impairments in perceiving facial emotions especially in comprehending negative emotions which may relate to early abnormal development of amygdale in ASD. The results also confirmed the former findings that perception of face is dependent on eye dominance in contrast to earlier literature of the lack of interest in eye region by people with ASD. These findings therefore give important insights into the social pathology of ASD and implications for future research and interventions.