Digit span, articulatory suppression, and the deaf: a study of the Hong Kong Chinese

Are the deaf capable of encoding, storing, and rehearsing visually presented information in phonological form? Using a working memory paradigm, the effect of articulatory suppression, a procedure consistently shown to eliminate phonological coding in hearing people, was examined for 15 orally trained, congenitally deaf, Hong Kong Chinese children. Digit span measures were obtained under normal conditions, with articulatory suppression, and kinesthetic suppression. Performance was compared to a control group of hearing children matched for educational level. Digit span measures for the deaf were lower compared to controls for all three conditions. However whereas suppression had a deleterious effect on digit span compared to both normal and tapping conditions for hearing subjects, no differences were observed for the deaf. The present results suggested that orally trained Chinese deaf did not encode information in an exclusively phonological manner and indicated the use of multiple encoding strategies. Given the possibility of differences between Chinese language processing compared to other language systems it would be injudicious to extend the present findings to all deaf populations pending further research.