The occurrence of homonymous visual field defects in patients with organic brain damage indicates a functional defect in the posterior region of the cerebral hemisphere contralateral to the impaired visual field.3 In addition to the direct effects of impairment of the visual fields, therefore, braindamaged patients with right homonymous visual field defects might be expected to exhibit symptoms of left hemisphere damage, and brain-damaged patients with left homonymous visual field defects might be expected to exhibit symptoms of right hemisphere damage. The present investigation was one of several studies intended to explore possible differential changes of behavior that may occur in relation to the side of the visual field that is impaired in patients with homonymous visual field defects. Brain-damaged patients with left homonymous visual field defects, brain-damaged patients with right homonymous visual field defects, brain-damaged patients with no evidence of visual field defects, and nonbrain-damaged control subjects