Abstract: The asymmetry of hemisphric function in recognizing Chinese single words by normal hearing Ss and prelingually deaf Ss were compared by using tachistoscopic method. The results indicated that the two groups had opposite hemispheric advantage both when the test words were presen- ted unilaterally and when they were presented simultaneously to the right and left visual field, i.e., the deaf Ss showed the left visual field advan- tage (the right hemisphere) and the normals showed that of the right visual field (the left hemisphere). However, the functions of the left hemisphere in the deaf declined while their right hemisphere functioned as well as the normals', which suggested that the absence of the speech perception imp- eded severely the normal development of the left hemisphere function me- diated by phonological and phonetic information processing. In recognition processing of Chinese characters, the speech sound was probably an im- portant factor to determine cerebral lateralization. There was no difference between the right and left visual fields in the recognition of Arabic num- erals for both groups.

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