Dominance of touch by vision: generalization of the hypothesis to a tactually experienced population.

It is now held that in conditions where there is conflicting sensory information vision dominates touch. The present study was designed to place boundary conditions on the generality of the hypothesis by comparing the performance of tactually experienced subjects - potters - with university students on a form-perception task in which a square was optically distorted so as to appear rectangular. Subjects examined the square haptically and visually, and matched it by touch or vision. Although potters were more accurate than students when not permitted vision, tactual judgements of both were dominated by vision when they were presented with conflicting information. In a supplementary study longer, more active exploration and emphasis on the necessity of matching by touch had no differential effect. In a third study it was found that a range effect produced by the comparison stimuli could explain the lesser accuracy of the students when they were making haptic judgements. The generality of the hypothesis that vision dominates touch is strengthened by our failure to refute it.