International Meeting for Autism Research: 3D-Multiple Object Tracking in Autism

3D-Multiple Object Tracking in Autism

Thursday, May 20, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
9:00 AM
E. M. Hahler , Visual Psychophysics and Perception Laboratory, Université de Montréal, Montréal, QC, Canada
D. Tinjust , Visual Psychophysics and Perception Laboratory, Université de Montréal, Montréal, QC, Canada
L. Mottron , Centre d'excellence en Troubles envahissants du développement de l'Université de Montréal (CETEDUM), Montréal, QC, Canada
J. Faubert , Visual Psychophysics and Perception Laboratory, Université de Montréal, Montréal, QC, Canada
Background: Multiple object tracking (MOT) is the capacity to allocate attention simultaneously to different areas in order to track multiple moving objects (Pylyshyn & Storm, 1988). Whereas there is evidence for superior visual search performance for static and dynamic targets in autism (O'Riordan et al., 2001; Joseph et al, 2009), autistic people display reduced perception in a subgroup of motion integration tasks (Bertone et al., 2003). The contribution of these contradictory abilities to the capacity to track multiple moving objects in autism is unknown.

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.

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