Abstract
Numerous studies report advantages in conjunctive visual search tasks in autism spectrum conditions (ASC) relative to neurotypical subjects, demonstrating faster responses that are less impacted by set size for individuals with ASC. However, these classic studies investigate behavior under tightly controlled conditions, where head-restricted participants locate a minimalistic target in a cluttered array presented on a computer screen. Here, we use virtual reality (VR) to investigate whether individuals with ASC exhibit performance advantages under naturalistic viewing conditions. 43 adult individuals (18 ASC) completed two visual search tasks in head-mounted VR: (1) a classic conjunctive search task in artificial arrays (2) a naturalistic search task inside immersive, real-world scenes. In the classic search task, participants searched for a target (e.g., red “T”) within a simple array of colored letters (e.g., black “T”s and red “L”s) using only eye-movements. In the naturalistic search task, participants looked for an object (e.g., “grey donkey”) within their environment using both head turns and eye movements. We tested how set size, a property known to limit visual search performance within computer displays, impacted the efficiency of visual search behavior. Within each task and group we found that reaction times slowed as set size increased (all p<0.001). Surprisingly, in both the classic and naturalistic visual search paradigms, individuals with ASC exhibited longer reaction times than control individuals (all p<0.05) and the two groups were equally affected by set size (both p>0.51). Interestingly, individual efficiency in the classic visual search task was predictive of naturalistic visual search efficiency for controls (rho=0.537, p<0.05) but not for individuals with ASC (rho=-0.057, p=0.824). These results question the common finding of visual search superiority in autism, suggesting instead comparable search efficiency as a function of set size in both computer-based and active, real-world visual environments.