Verbal working memory and sentence comprehension: A multiple-components view.

Semantic and syntactic aspects of sentence comprehension were investigated for 3 patients who showed different patterns of performance on short-term memory tasks. On a sentence anomaly judgment task assessing the retention of semantic information, only patient A.B. showed a detrimental effect on comprehension with increases in the number of words to be held in an unintegrated fashion. On judgments of grammatical acceptability, only patient M.W. demonstrated a detrimental effect of increasing the number of words intervening between the words signaling that a sentence was ungrammatical. The results suggest that semantic and syntactic components must be postulated in addition to the phonological and articulatory components of A. D. Baddeley's (1986, 1990) working memory model. Although the phonological, semantic, and syntactic components may be differentiall y affected by brain damage, the components interact and support each other in normal comprehension. The working memory model initially proposed by Baddeley and Hitch (1974) has played an important role in neuropsychological studies of brain-damaged patients with language disorders. The essential insight of their model was that working memory should not be seen as a unitary store, but rather as consisting of different components with separate storage capacities. It differed in this respect from the so-called modal model of memory (Murdock, 1974), which posited a single store in which information of all types was maintained prior to transfer to long-term memory (e.g., Atkinson Waugh Vallar & Baddeley, 1984a).