Towers of Hanoi and London: contribution of working memory and inhibition to performance.

The Tower of Hanoi and Tower of London have become well-established executive function tasks that presumably tap cognitive skills mediated by the frontal cortex. It has been assumed that the two tower tasks are more or less interchangeable and that both measure working memory and inhibition processes. These assumptions were tested in a study involving 37 normal college volunteers (M age = 20 years). Participants were administered the Tower of Hanoi (TOH), Tower of London-Revised (TOL-R), two working memory tests, and two tests of inhibition. The two tower tasks correlated significantly (r = .39), but only moderately. The working memory and inhibition variables explained over one-half of the variance in TOL-R performance; however, there was a relatively weaker contribution of inhibition to TOH performance.