Performance of blind and sighted humans on a tactile grating detection task
We compared the abilities of blind and sighted humans to distinguish grooved from smooth surfaces pressed against the stationary index fingertip. Ranging in age from 20 to 72 years, 37 blind and 47 sighted subjects participated in an automated two-alternative forced-choice tactile grating detection task. The tactile acuity of blind and sighted subjects declined with age at equivalent rates (0.011-mm threshold increase per year), but the blind subjects were able to perceive significantly thinner grooves than were their sighted peers (the average difference between blind and sighted subjects of the same age and gender was 0.267 mm). The blind Braille readers performed no better than the blind nonreaders, and the congenitally blind subjects performed equivalently to those with adult-onset blindness. The superior tactile acuity of blind persons may result from the involvement of normally visually responsive cerebrocortical areas in tactile processing, as shown by functional-imaging studies.
- Axelrod, S. (1959).Effects of early blindness: Performance of blind and sighted children on tactile and auditory tasks. New York: American Foundation for the Blind.Google Scholar
- Hollins, M. (1989).Understanding blindness: An integrative approach. Hillsdale, NJ: Erlbaum.Google Scholar
- Sterr, A., Müller, M., Elbert, T., Rockstroh, B., &Taub, E. (1999). Development of cortical reorganization in the somatosensory cortex of adult Braille students.Electroencephalography & Clinical Neurophysiology,49(Suppl.), 292–298.Google Scholar
- Warren, D. H. (1978). Perception by the blind. In E. C. Carterette & M. P. Friedman (Eds.),Perceptual ecology (Handbook of Perception, Vol. 10, pp. 65–90). New York: Academic Press.Google Scholar