The Effect of Irrelevant Visual Input on Working Memory for Sign Language

We report results showing that working memory for American Sign Language (ASL) is sensitive to irrelevant signed input (and other structured visual input) in a manner similar to the effects of irrelevant auditory input on working memory for speech. Deaf signers were disrupted on serial recall of lists of ASL signs when either pseudosigns or moving shapes were presented during a retention interval. Hearing subjects asked to recall lists of printed English words did not show disruption under the same interference conditions. The results favor models that hypothesize modality-specific representations of language within working memory, as opposed to amodal representations. The results further indicate that working memory for sign language involves visual or quasi-visual representations, suggesting parallels to visuospatial working memory. We have previously argued that the structure of work-ing memory for sign language is highly similar to work-ing memory for spoken language (Wilson & Emmorey, 1997, 1998). Evidence for the architecture of speech-based working memory derives in part from the phono-logical similarity effect, the articulatory suppression effect, and the word length effect. Previous work has found par-allel effects for sign language, suggesting that workin