Figure 2

Baseline-corrected pupil response during visual search.

Results are shown for single-feature, set size 5 feature-conjunction and set size 9/13 feature-conjunction conditions, averaged over trials and participants in each group (N = 17 for ASD group; N = 17 for age-matched TD controls; panels (a), (b) and (c), respectively). Error bars indicate standard errors of the mean. Two-tailed t-tests at the end of the search interval showed significantly greater dilation in the ASD group in all three cases. Histograms of dilation at the end of the search interval, for all trials, are shown for ASD and TD groups (panel d, top and bottom, respectively). Normal fits are shown. The ASD group shows greater phasic pupil response, indicative of greater phasic LC-NE activity and attentional focus.