SIGN LANGUAGE, WORKING MEMORY AND BRAIN ACTIVITY

The article in the first part investigates the different coding strategies used by deaf signers in short term memory. The deaf signers lack the use of the phonetical-acoustical coding but they are capable sometimes to use the articulatory code. It becomes also clear that it is possible to use the signs efficiently as a code if the presentation of the items is in the same modality. The use of the signs in short term memory tasks depends on the abilities and linguistic competencies of the deaf signers. Despite the difference in short term memory span, hearing speakers and deaf signers have comparable working memory resources during language use, indicating similar abilities to maintain and manipulate linguistic information online. The auditory system is known to be highly efficient in retaining the order of occurrence of sounds. It is possible that speakers and signers may encode order information in quite different manners, speakers relay predominantly on temporal encoding and signers predominantly on spatial encoding. The sign language is a natural language and thus presents an opportunity to examine the neural organisation of language. In the second part of this article the author analyses the way the different sensorial modality can influence the neural representation of language. In his view there is a strong similarity between the regions activated within the left hemisphere by sign language in deaf individuals, compared with those activated by spoken language in hearing individuals. This may suggest that the cortical neural organisation of language processing does not depend on the different sensorial inputs but it is determined by the inner structure of the natural language.