Global spatial organization by individuals with Williams syndrome

Williams syndrome is a genetically determined disorder with a characteristi c cognitive profile. Overall IQ tends to be lower than in the normally deve loping population, performance on measures of linguistic ability is somewha t higher than would be expected given the levels of IQ typical for this gro up, and there is a particular weakness in visuospatial construction (e.g., block design tasks). A well-known hypothesis about the deficit in visuospat ial construction is that people with Williams syndrome are strongly incline d to be focal spatial processors. We report a test of this hypothesis that used a visual search task sensitive to spontaneous global spatial organizat ion A sample of adults with Williams syndrome produced a pattern of data de monstrating that they spontaneously organize spatial displays at a global l evel. Indeed, individuals with Williams syndrome found it more difficult to change from global to local processing than participants with normal intel ligence. We suggest that the primary problem with visuospatial construction in people with Williams syndrome is not in the salience of single levels o f organization but rather in the difficulty of changing between organizatio ns.