The perception of tactile distance: Influences of body site, space, and time

Abstract

Vibrotactile stimuli are often presented to different body sites. Of the many factors that can affect identification of such patterns are the body site tested and the spatiotemporal influences of nearby stimuli. The data obtained by Kaas, Merzenich, and their colleagues indicate that the degree of “cortical magnification” across different body regions is inversely related to cutaneous receptive field size. Consequently, measures influenced by field size should show similar variation. Geldard and Sherrick have shown such a variation in one tactile illusion, cutaneous saltation. In the series of studies to be discussed, magnitude and matching judgments of patterns consisting of stimuli presented to separated sites, either within tactile matrixes or across separate larger contactors, demonstrate that apparent distance on the skin is inversely related to the interstimulus interval between the two stimuli, directly related to the physical separation between the two, and shows a consistent relationship to cortical magnification. [Work supported by NIH grant NS-04775.]