When do individuals with autism spectrum disorder show superiority in visual search?

Although superior visual search skills have been repeatedly reported for individuals with autism spectrum disorder, the underlying mechanisms remain controversial. To specify the locus where individuals with autism spectrum disorder excel in visual search, we compared the performance of autism spectrum disorder adults and healthy controls in briefly presented search tasks, where the search display was replaced by a noise mask at a stimulus-mask asynchrony of 160 ms to interfere with a serial search process while bottom-up visual processing remains intact. We found that participants with autism spectrum disorder show faster overall reaction times regardless of the number of stimuli and the presence of a target with higher accuracy than controls in a luminance and shape conjunction search task as well as a hard feature search task where the target feature information was ineffective in prioritizing likely target stimuli. In addition, the analysis of target eccentricity illustrated that the autism spectrum disorder group has better target discriminability regardless of target eccentricity, suggesting that the autism spectrum disorder advantage does not derive from a reduced crowding effect, which is known to be enhanced with increasing retinal eccentricity. The findings suggest that individuals with autism spectrum disorder excel in non-search processes, especially in the simultaneous discrimination of multiple visual stimuli.