Letters to Nature

Nature 395, 278-280 (17 September 1998) | doi:10.1038/26228; Received 23 February 1998; Accepted 19 June 1998

Early-blind human subjects localize sound sources better than sighted subjects

N. Lessard1, M. Paré2, F. Lepore1,2 & M. Lassonde1,2

  1. Groupe de Recherche en Neuropsychologie Exprimentale, Département de Psychologie, and Centre de Recherche en Sciences Neurologiques, Université de Montréal, C.P. 6128, Succ.Centre-ville, Montréal, Québec H3C 3J7, Canada
  2. Centre de Recherche en Sciences Neurologiques, Université de Montréal, C.P. 6128, Succ.Centre-ville, Montréal, Québec H3C 3J7, Canada

Correspondence to: F. Lepore1,2 Correspondence should be addressed to F.L. (e-mail: Email: leporef@ere.umontreal.ca).

Do blind persons develop capacities of their remaining senses that exceed those of sighted individuals? Besides anecdotal suggestions, two views based on experimental studies have been advanced1. The first proposes that blind individuals should be severely impaired, given that vision is essential to develop spatial concepts2. The second suggests that compensation occurs through the remaining senses, allowing them to develop an accurate concept of space3. Here we investigate how an ecologically critical function, namely three-dimensional spatial mapping, is carried out by early-blind individuals with or without residual vision. Subjects were tested under monaural and binaural listening conditions. We find that early-blind subjects can map the auditory environment with equal or better accuracy than sighted subjects. Furthermore, unlike sighted subjects, they can correctly localize sounds monaurally. Surprisingly, blind individuals with residual peripheral vision localized sounds less precisely than sighted or totally blind subjects, confirming that compensation varies according to the aetiology and extent of blindness4. Our results resolve a long-standing controversy in that they provide behavioural evidence that totally blind individuals have better auditory ability than sighted subjects, enabling them to compensate for their loss of vision.