Language Processing and Working Memory: Neuropsychological Evidence for Separate Phonological and Semantic Capacities

Abstract The short-term memory and sentence-processing abilities of two brain-damaged patients were investigated. Although both patients showed similar reductions in span, one patient showed worse retention on span tasks for semantic than phonological information, whereas the other patient showed the reverse. Their performance on the sentence-processing tasks was consistent with these contrasting short-term memory deficits. On sentence repetition, the patient with the phonological retention deficit was more impaired than the patient with the semantic retention deficit, whereas on sentence comprehension, the patient with the semantic retention deficit was more impaired. The results imply that the memory processes involved in span overlap with those involved in sentence processing. Furthermore, the dissociations in the patients′ performance imply that there are separate capacities for phonological and semantic retention. Thus, the results support a multiple-capacity rather than a single-capacity view of working memory.