Visual Fixation Patterns During Viewing of Naturalistic Social Competence in Individuals With Autism

Klin, A., Jones, W., Schultz, R., Volkmar, F., and Cohen, D., (2002), Arch Gen Psychiatry, Vol 59, Pages 809-814.

Background
To bring experimental measures in line with clinical observation, we report a novel method of quantifying atypical strategies of social monitoring in a setting that simulates the demands of daily experience.

Methods
While viewing social scenes, eye-tracking technology measured fixations in 15 cognitively able males with autism and 15 age-, sex-, and verbal IQ- matched control subjects. We reliably coded fixations on 4 regions; mouth, eyes, body, and objects. Statical analyses compared fixation time on regions of interest between groups and correlation of fixation time with outcome measures of social competence.

Results
Significant between-group differences were obtained for all 4 regions. The best predictor of Autism was reduced eye region fixation time. Fixation on mouths and objects was significantly correlated with social functioning; increased focus on mouths predicted improved social adjustment and less autistic social impairment, whereas more time on objects predicted the opposite relationship.

Conclusions
When viewing naturalistic social situations, individuals with autism demonstrate abnormal patterns of social visual pursuit consistent with reduced salience of eyes and increased salience of mouths, bodies, and objects. Fixation times on mouths and objects but not on eyes are strong predictors of degree of social competence.

The fact that percentage of time focused on eyes was unrelated to measures of social competence suggests the possibility that for individuals with autism, looking at eyes does not accrue considerable advantages in their efforts to understand social situations, or, in other words, the eyes are not meaningful to them. The hypothesis that increased fixation on mouths results from concentration on speech needs to be further refined on the basis of what we know about visual attention to facial regions in speech perception tasks.

On the basis of this literature, our visual fixation results could suggest that our participants were not only focusing on the verbal content of speech but were also ignoring paralinguistic cues such as prosody, which are usually essential to understanding nonliteral aspects of social situations such as intentions and attitudes. In other words our findings could be related to the over-reliance of individuals with autism on the literal aspects of speech at the expense of intonational cues associated with social meaning.

Another line of enquiry for future studies relates to the possibility that increased fixation on mouths and decreased fixation on eyes indicates that individuals with autism may acquire a degree of perceptual expertise on mouths but not eyes.