Tiffany and I will be attending the SFN conference in Washington, DC to present our Autism research.
Lazar, T., Shomstein, S., & Marotta, J.J. (2014). Parts-Based Processing in Autism. Program No.. 2014 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience. Online.
Research suggests that individuals with autism spectrum disorders (ASD) process their environment in a local, parts-based manner (Happé & Frith, 2006; Plaisted et al., 1999). This local bias could possibly be driven by difficulties in grouping stimuli based on Gestalt principles, an early pre-attentional perceptual system required for perception of global structures (Han & Humphreys, 1999). We tested this hypothesis by adopting a Moore & Egeth, 1997 paradigm, in which the Ponzo illusion was induced by a set of background dots that surrounded two solid lines. The illusion could only be induced by the virtue of perceptually grouping the background dots into lines based on color similarity. We hypothesized that adults with high functioning ASD are less susceptible to the effects of the illusion than typically developing controls, due to a tendency to process the items in a parts-based manner (i.e., failing to group the background). A line discrimination task was administered in which two horizontal lines were superimposed on a background of black and white dots. On occasion, black and white background dots were presented so that if automatically grouped and integrated, they should influence the perceived length of the horizontal lines. Results showed that on average, individuals with ASD were significantly less likely than controls to report an illusion-based response. In fact, the mean percent correct for responding consistently with the illusion did not differ significantly from 50% in the ASD group, indicating at chance performance. These results suggest that individuals with ASD experience deficits in perceptual grouping abilities at early, pre-attentive levels of visual processing. Difficulties in grouping stimuli according to Gestalt principles may explain why individuals with ASD are less inclined to use global context very early in perception and tend to rely on local visual processing strategies. These findings may have broader implications in forming behavioral therapies and intervention strategies that help address the unique way that individuals with ASD process the world, leading to improved quality of life in the classroom, workforce, and society in general.
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