Abstract
Atypical global-local processing and heightened visual perceptual skill has been consistently described across autism spectrum disorders (ASD). In three eye tracking studies using hierarchical Navon stimuli, we assessed the utility of a novel trajectory-based analysis to quantify dynamic changes in pupil response in the context of visual selection and perception. As a critical first step, we implemented this analysis in healthy adults (N=33) to establish pupil response differences that underlie the selection of local versus global information (Study 1). Results indicated a characteristic constriction in the pupil waveform during the identification of local as compared to global information. In Study 2, we extended this research to a pediatric sample of children (N=34) with and without ASD. Using the combined trajectory patterns across global and local conditions, we identified three, task-induced pupil trajectory groups that may reflect different perceptual strategies. The proportion of children with a diagnosis of ASD was significantly larger in a ‘Local-Focus’ trajectory group, which was characterized by a narrowing of the pupil when identifying local information. The results from Study 1 and Study 2 indicate that pupil changes may serve as a visual filtering mechanism important for selection that may also underlie the atypical visual processing strategies of individuals with ASD. Finally, in Study 3, we used the same Navon stimuli in a modified task-switching paradigm that required increased cognitive effort, asking participants (N=33) to identify either global or local information based on a visual cue. Again, we identified three task-induced pupil trajectory groups and found higher scores on a quantitative measure of ASD traits associated with a particular trajectory group. Taken together, these results demonstrate the utility of individualized pupil response trajectories in understanding variations in visual selection and perceptual skill across the ASD phenotype.