Contextual Information Modulates Pupil Size in Autistic and Non-Autistic Children.

Abstract

\n Background. Recent Bayesian models suggest that perception is more “data-driven” and less dependent on contextual information in autistic individuals than others. However, experimental tests of this hypothesis have given mixed results, possibly due to the lack of objectivity of the self-report methods typically employed. Here we introduce an objective no-report paradigm based on pupillometry to assess the processing of contextual information in autistic children and a comparison clinical group.Methods. After validating (in a group of neurotypical adults) a child-friendly pupillometric paradigm, in which we embedded test images within an animation movie that participants watched passively, we compared pupillary response to images of the sun and meaningless control images in children with autism versus age- and IQ-matched children presenting developmental disorders unrelated to the autistic spectrum. Results. Both clinical groups showed stronger pupillary constriction for the sun images compared with control images, like the neurotypical adults. There was no detectable difference between autistic children and the comparison group (in spite of a significant difference in pupillary light responses, enhanced in the autistic group). Limitations: Having found no statistically significant differences between groups, we cannot exclude that group differences existed but were too small to be detected – a critique that applies to most negative findings. Additional limitations concern the heterogeneous composition of the comparison group and the types of stimuli tested, which only allowed for studying the effect of context on relatively complex perceptual processes. Conclusions: Our report introduces an objective technique for studying perception in clinical samples and children. The lack of statistically significant group differences in our tests suggests that autistic children and the comparison group do not show large differences in perception of these stimuli. This opens the way to further studies testing contextual processing at other levels of perception.