Zoe (Jing) Xu¹, Bridget Leonard¹, Kristin Woodard¹, Hannah Rea¹, Sara J. Webb², Scott O. Murray¹; ¹University of Washington, ²Seattle Children’s Research Institute

For the past 25 years, research has consistently shown that autistic individuals search faster than neurotypicals, but the underlying reasons remain unclear. Here, we conducted six experiments to clarify differences in search performance between autistic and neurotypical individuals. Participants (32 autistic and 40 non-autistic adults) completed four classic search tasks: a conjunction search (finding the letter R among Ps and Qs), a difficult feature search (ellipse among circles), a moderate feature search (letter N among Ps and Qs), and a color search with varying levels of difficulty (target color among distractor colors). We measured search time and eye movements. In two additional psychophysical experiments, we used a staircase procedure to estimate threshold display durations and color discriminability during a color search task. Across the four classic search experiments, we did not observe significant group differences in search speed. However, there was a trend that autistic participants searched faster at a moderate-to-easy difficulty level (e.g., searching for a target color among a similar distractor color), but not in harder conjunction/feature searches or easier color-search conditions. This potential advantage may stem from their distinct search patterns observed in the eye-tracking data: at moderate difficulty, autistic participants used a larger functional viewing fields that covered more items, fixated for longer durations, and made saccades that covered a smaller convex hull area. Results from the psychophysical experiments also showed that autistic participants required shorter display durations at larger target eccentricities, suggesting faster peripheral visual processing. Together, these findings indicate that the critical distinction between groups lies in their use of peripheral vision: autistic individuals appear to rely more on parallel processing with peripheral vision and less on serial, item-by-item examination. Our results refine previous accounts of enhanced search performance in autism and suggest differences in underlying visual mechanisms, such as a peripheral vision preference.

Acknowledgements: NIH R01MH131595 to S.O.M. and S.J.W.