Cube copying after cerebral damage.

The capacity of patients with cerebral lesions to copy a picture of a cube, as opposed to a nonrepresentational figure of similar structural complexity, was examined. Patients with copying disability showed greater impairment for the cube than the noncube whereas patients without copying impairment and controls performed equally on the two figures. It was concluded that the copying-deficit patients had particular difficulty in drawing 3-dimensional figures and that the copying deficit was not simply one of formulating the sequence of steps necessary to produce a complex as opposed to a simple abstract form. The results suggest that copying-disability patients may experience particular difficulty in encoding the pictorial structure of a model which depicts a three-dimensional object. The occurrence of errors of intellectual realism in cube copying (which also occur in children's drawings) was noted and it was suggested that the patients were experiencing difficulty in perceptually isolating the picture structure from the picture content.