Gestalt processing in autism: failure to process perceptual relationships and the implications for contextual understanding

Background: Deficits in autism have been characterised as a bias towards local over global processing. This paper examines whether there is a deficit in gestalt grouping in autism. Method: Twenty-five low-functioning children with autism and 25 controls who were matched for chronological age and verbal mental age took part in the study. Results: The autism group utilised gestalt grouping principles (proximity, similarity, closure) significantly less than the controls. Calculating an overall index of gestalt grouping, the autism group performed at chance level. There was also a deficit in identifying certain impossible figures. This pattern was not reflected in a drawing task, in which the autism sample conformed more to gestalt grouping principles than controls (non-significantly). Conclusions: The results are discussed in terms of a failure in autism to process inter-element relationships that would allow for the appreciation of larger perceptually coherent units that comprise of multiple elements and, consequently, context. The processes are argued to be preattentive.