When task demands induce “asyntactic” comprehension: A study of sentence interpretation in aphasia

Abstract

Abstract We investigated sentence processing in two aphasic patients who appeared to have asyntactic comprehension when tested using sentence-picture matching. It was found that neither patient could handle the nonlinguistic cognitive demands of the original task: Specifically, processing two semantically incongruous inputs (sentence plus reverse-role picture) overloaded working memory. Their ability to deal with semantic conflict in the absence of multiple inputs was examined in an interleaved meaning-classification/actor-identification task. The patients rarely accepted misordered sentences like The cheese ate the muse as plausible, but performed poorly when asked to identify the “actors” in such sentences, often selecting the more likely alternative (the mouse). We concluded from this dissociation between tasks that semantic conflict only overtaxed their limited processing capacity when the conflicting options were explicitly available and directly relevant to the decision process. There was, therefore...