Two versions of the Tower of Hanoi task were used to investigate different components of learning and problem solving in schizophrenia. Prior studies have suggested that a three-disk version (Tower 3), which involves primarily problem-solving abilities and planning, is preferentially sensitive to frontal lobe lesions and that the more difficult four-disk version (Tower 4), which involves "learning by doing," is sensitive to basal ganglia disease. Schizophrenic patients performed significantly worse than normal subjects on Tower 3 and Tower 4. However, they performed at least as well relatively on Tower 4 as on Tower 3, indicating that level of difficulty per se does not account for their poor performance on these tasks. Moreover, they eventually attained perfect or near-perfect performance after four days of repeated administration. Their relatively stronger performance on Tower 4 may have reflected an ability to acquire a procedure and, as such, suggests greater preservation of basal ganglia function than of prefrontal function.Abstract Teaser