Asymmetries for Ameslan handshapes and other forms in signers and nonsigners

Toward an evolutionary perspective on hemispheric specialization

“…Incidentally, if McKeever were right in claiming that only the prelinguistically deaf substantially lack left-hemisphere linguistic specialization, this would itself tend to confirm the priority of the latter specialization over language. However, according to Virostek and Cutting (1979), RVF superiorities are equally strong (with American Sign Language shapes) for both the congenitally deaf and the hearing. These authors have reviewed other studies that have found this, and conclude that auditory experience is unnecessary for lateral specialization per se, and that cerebral specialization for language is generally similar for deaf native signers and for nondeaf native speakers of any oral language.…”

The Effects of Auditory and Linguistic Deprivation on Lateral Preferenceof Deaf Children

“…Although the evidence on hemisphere specialisation among the deaf is not totally uniform [see Virostek and Cutting (1979) for a negative finding] and is clearly dependent on the type of stimuli used, certainly it would appear that auditory and language deprivation is associated with a changed pattern of hemisphere specialisation. One important aspect of this evidence of reduced or altered cerebral assymetry is the implication that the functional organisation of the brain is not irreversibly preprogrammed and therefore may be affected by specific types of early experience.…”