Visual hierarchical analysis of Block Design configural errors.

Patients have been frequently observed to violate the overall configuration on the WAIS-R Block Design subtest. The significance of these configural errors was investigated with hierarchical patterns consisting of large "global" shapes made from smaller "local" shapes. Subjects were administered two similarity judgment tasks in which they were asked to decide which of two hierarchically structured comparison figures most resembled a standard figure. Results indicated that subjects who made configural errors on Block Design were less likely than a matched sample who did not make configural errors to select the comparison figure that resembled the standard figure at the global level. Furthermore, the present findings were obtained from subjects without known right-hemisphere lesions, suggesting that the correlation between Block Design errors and global/local performance is applicable to a broad range of patient and non-patient populations. The data are consistent with the view that errors on Block Design may reflect differences in the perceptual encoding of global/local features.