Objectives: Evaluate 3D-MOT capacities in individuals with autism in a fully immersive virtual environment (with stereoscopic vision).
Methods: 10 autistic adults with typical intelligence and 10 matched control subjects tracked either 1 (single) or 3 (multiple) previously indexed target objects in a set of 8 moving spheres and verbally identified the sphere or the three spheres that they considered to be the targets. Performances were measured based on speed thresholds, which evaluate the greatest speed at which observers are capable to track the moving objects. A correct answer was considered as the identification of all the targets. All other responses were considered false. An adaptive staircase protocol (one down/one up) was used in order to adjust the speed of the moving spheres between trials relative to the subject’s answer. Participants were matched on age (mean age of 23.6 years), gender (9 males and 1 female) and IQ (mean IQ of 106.5), based on the Wechsler Adult Intelligence Scale.
Results: Results showed that for both groups speed thresholds were higher, and thus reflected better performance, for the single-object tracking versus the multiple-object tracking condition. Autistics were capable of tracking a single sphere among a set of distractors as well as the comparison group. However, a significant group x condition interaction was found between groups in their multiple-object tracking capacities, showing that autistics, as a group, were less able to track multiple moving objects, and that they seem thus less capable to allocate their attention to different areas at the same time.
Conclusions: Autistic documented superiority in visual search may find its limit when targets are numerous and moving in unpredictable directions.