Memory span for Arabic numerals and digit words in Japanese kanji in deaf signers

Abstract

According to the theory of working memory, the "phonological loop" is a slave system that stores a limited number of sounds for a short period of time. The question of how this system works for deaf people reading a logographic script, kanji, was investigated. We measured the memory span of a sample of Japanese hearing and deaf participants. Hearing subjects were tested in Japanese and deaf subjects in sign language. Memory span was assessed in control and articulatory suppression conditions. In the control condition, subjects were required to recall various item sequences as quickly and accurately as possible. In the articulatory suppression condition, the hearing subjects articulated the phrase no-no, and the deaf subjects expressed a pseudosign, while viewing the stimuli. Results showed that the memory span of the deaf for Japanese kanji was similar to that of their hearing peers. This finding conflicts with previous research which suggested that for users of English, the deaf display consistently shorter memory spans than do their hearing counterparts. In addition, we discovered that in contrast to their hearing colleagues, the deaf Japanese subjects were relatively immune to expected articulatory suppression effects. This finding raises the possibility that working memory coding processes are not universal.