Visual-haptic relations in a two-dimensional size-matching task.

Visual and haptic perceptions of the two-dimensional size of square stimuli were compared using cross-modal, intramodal, and bimodal matching tasks. In a repeated-measures factorial design, 12 women participated in five matching tasks involving various combinations of vision and haptic touch; five sizes of standard squares were matched with a comparison range of 10 squares during each task. Analysis showed that, for stimuli with side lengths of .75 in. and smaller, matching accuracy was superior when vision was used during the matching task regardless of the modality used during inspection. When haptic touch was used in the matching task, accuracy was better when vision had been used during inspection than when it had not. These results were consistent with those of previous studies comparing size perception by vision and other forms of touch. The over-all relationship between matched size and inspected size was best accounted for by a third-order polynomial function.