Signs as pictures and signs as words: effect of language knowledge on memory for new vocabulary

The role of sensory attributes in a vocabulary learning task was investigated for a non-oral language. Deaf and hearing individuals, more or less skilled in the use of sign language, were asked to learn the English meanings of 22 invented signs which followed the rules of formation for signs in American Sign Language. Each sign stimulus was highly similar in formation to another sign in the set. It was expected that skilled signers would be less affected by this formational similarity because of their greater familiarity with the linguistic structure of sign language. Furthermore, it was suggested that skilled signers would form a visual-linguistic code for the signs while unskilled signers would produce a code from general visual-pictorial processes. These representation differences were expected to lead to qualitatively different error patterns in response to sign similarity. All expectations were confirmed. Skilled signers encoded invented signs in terms of linguistic structure, while unskilled individuals approached the signs as visual-pictorial events. Although both codes are sensory, one reflects linguistic abstraction, and the other does not.