Sorting tasks, requiring the subject to respond selectively, first to one aspect of a situation and then to another, have traditionally been regarded as sensitive indicators of brain injury, but there has been little agreement concerning the effects of lesions in different areas of the brain on sorting behavior. Weigl,36in 1927, found that braininjured patients performed more poorly than normal control subjects on a simple Color-Form sorting task, and he described a patient with bilateral frontal-lobe damage who had particular difficulty in shifting from one sorting principle to another. Goldstein,6though rejecting any strict localization of intellectual function, also appears to stress the importance of the frontal lobes for spontaneous shifting, and this view has been further emphasized by such workers as Rylander29and Halstead.9,10Yet Teuber, Battersby, and Bender,34studying men with penetrating missile wounds of the brain, found greater deficits on