Are the frontal lobes implicated in "planning" functions? Interpreting data from the Tower of Hanoi.

Twenty adult patients with lesions in the prefrontal cortex were tested on the Tower of Hanoi puzzle. The performance of patients was significantly worse than that of controls. This difference could not be accounted for in terms of a general decline in intelligence or memory, or by the size of the lesion. The results further suggest that both patients and controls used the same general strategy to solve the problem and that patients' difficulties with the task have little to do with planning or "look ahead" deficits (as is generally assumed in the neuropsychology literature). Patient performance is best explained in terms of an inability to see or resolve a goal-subgoal conflict. This interpretation is compatible with several existing accounts of frontal lobe dysfunction that postulate a failure of inhibition of a prepotent response to explain poor performance on the Wisconsin Card Sorting task, the Stroop task, the Antisaccade task, the A-Not-B task, and the Delayed Alternation task.