WORKING-MEMORY CAPACITY DISSOCIATES LEXICAL AND SENTENTIAL CONTEXT EFFECTS

Semantically associated and unassociated word pairs were embedded in n ormal meaningful sentences and in sentences that were semantically ano malous throughout. The influence of lexical context was isolated via c omparison of responses to the second words of the associated and unass ociated pairs. The influence of sentence-level context was isolated by comparing responses to the same words in the two sentence types. Subj ects of high, medium, and low working memory capacity (as evaluated by the reading span test) showed modulations of event-related brain pote ntials in response to lexical context. In contrast, only the high- and medium-capacity groups were responsive to purely sentence-level seman tic context. The results demonstrate that sentential context influence s the processing of words in intermediate sentence positions at normal reading speeds, but that the on-line utilization of this context is m ore demanding of working memory than single-word contexts.