Retroactive and proactive interference effects in dual learning of blissymbolics and manual sign

Nonspeech systems can be either aided or unaided. Each system possess its unique learning and memory characteristics. One instructional strategy designed to give learners the advantages of both systems is dual instruction in aided and unaided communication. One problem with this approach, however, might be that of retroactive and proactive interference in learning and memory. The current experiment investigated whether dual instruction in Blissymbolics and manual (ASL) sign would lead to retroactive and proactive interference. Lists of sign/symbol referents in the two systems were taught to nonhandicapped adults in a controlled setting. No effects of retroactive or proactive interference were found. Additionally, a proactive facilitation effect was found for immediate retention. Results are discussed in terms of the nature of the task, the learning memory attributes of the nonspeech systems, and the effects of sign/symbol translucency.