The Effect of Presentation Mode and Production Type on Word Memory for Hearing Impaired Signers

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.

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.

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.

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).

For each condition, we calculated the proportion of study words recalled. A mixed-design analysis of variance was conducted, with learning condition (written-vocalize, written-signed, and manual-signed) and production type (production and no-production) as within-subject variables, and group (MC and TC) as a between-subject variable.

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.

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.