Temporal and intensitive factors in comparative judgments of tactile space.

Temporal imbalances between the successive stimulation of pairs of loci on each forearm altered judgments of the equality of the spatial extents between sets of loci. The spatial judgments became increasingly inaccurate as the temporal imbalance was increased, i.e., the Tau effect. Changes in stimulus intensity also influenced the dependency of spatial judgments on temporal factors. The data suggest that concomitant variations of spatial, temporal, and intensitive components of a vibrotactile stimulus "package" can produce systematic perceptual effects of potential significance in the design of vibrotactile sensory substitution systems.