Combined frequency-tagging EEG and eye-tracking measures provide no support for the "excess mouth/diminished eye attention" hypothesis in autism.
Sofie Vettori, Stephanie Van der Donck, Jannes Nys and 6 others
PMID 33228763WHAT IT FOUND
Boys with autism looked at faces just as much as typical boys did, focusing on the eyes rather than the mouth.
Brain scans showed no difference in how they processed these features. The idea that autistic people avoid eyes is not supported by this data.
Key findings
01There were no significant group differences in the amount of time spent looking at the eyes or the mouth, or in the neural response to these regions.
02Both groups looked significantly more at the eyes than at the mouth, contradicting the 'excess mouth/diminished eye gaze' hypothesis.
03Autistic boys used a more exploratory face scanning strategy, switching between facial features more frequently than typical boys, despite similar total looking times at the eyes.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The sample was small (42 boys) and highly selective, consisting only of school-aged boys with average to above-average intelligence and no language deficits. The study used static, neutral faces without external features like hair, which lacks ecological validity compared to real-life social interactions. The findings may not generalize to girls with ASD, individuals with lower IQs, or those with severe social impairments. The classification of group membership based on gaze dynamics was only moderately accurate (72%), suggesting these patterns are not robust enough for diagnostic screening.
Declared interests
Funding was provided by the FWO, Excellence Of Science, and the Marguerite-Marie Delacroix foundation. The authors declared no conflicts of interest.
The easy way to misread this
Do not conclude that autistic children have typical social communication skills. While they looked at the eyes as much as peers, their scanning was more fragmented and exploratory, which may reflect a different perceptual style rather than a lack of social interest. Additionally, this study only included high-functioning boys, so results do not apply to all individuals with autism.