Tactile pattern recognition and its perturbations

Abstract

A number of devices developed to present information to the skin, including speech information, have tried to take advantage of the spatial-temporal processing characteristics of the skin. To study these characteristics, tactile patterns were generated on an array of vibrators (six columns by 24 rows) and presented to subjects' fingerpads. When pairs of patterns, such as letters of the alphabet, were presented in close temporal proximity, considerable masking was produced. There was more interference in recognition when the masking stimulus followed the target (backward masking), than when the masker preceded the target (forward masking). Masking increased as the time between the target and masking stimulus decreased. Masking also increased if the masking stimulus and the target contained similar features. Using tactile stimuli derived from speech information, it was also found that reducing the amount of backward masking, by reducing the duration of the vowel portion of a CV, improved recognition of the consonant. The critical temporal variable in measures of both masking and temporal integration appeared to be the time between the onsets of the successive patterns. [Work supported by NIH and NSF.]