The effect of presentation mode and production type on word memory for hearing impaired signers

Background: Production effect (PE) is a memory phenomenon referring to better memory for produced (vocalized) than for non-produced (silently read) items. Reading aloud was found to improve verbal memory for normal-hearing individuals, as well as for cochlear implant users, studying visually and aurally presented material. Purpose: The present study tested the effect of presentation mode (written or signed) and production type (vocalization or signing) on word memory in a group of hearing impaired young adults, sign-language users. Research Design: A PE paradigm was used, in which participants learned lexical items by two presentation modes, written or signed. We evaluated the efficacy of two types of productions: vocalization and signing, using a free recall test. Study Sample: Twenty hearing-impaired young adults, Israeli sign language (ISL) users, participated in the study, ten individuals who mainly use manual communication (MC) (ISL as a first language), and ten who mainly use total communication (TC). Data Collection and Analysis: For each condition, we calculated the proportion of study words recalled. A mixed-design analysis of variance was conducted, with learning condition (written-vocalize, writtensigned, and manual-signed) and production type (production and no-production) as within-subject variables, and group (MC and TC) as a between-subject variable. Results: Production benefit was documented across all learning conditions, with better memory for produced over non-produced words. Recall rates were higher when learning written words relative to signed words. Production by signing yielded better memory relative to vocalizing. Conclusions: The results are explained in light of the encoding distinctiveness account, namely, the larger the number of unique encoding processes involved at study, the better the memory benefit.