Sentence understanding and knowledge of the world: Evidences from a sentence-picture matching task performed by aphasic patients

The abilities of aphasic patients to perform a sentence-picture matching task were investigated on simple declarative reversible sentences. Two factors were found to differentially affect Broca's versus Wernicke's aphasics' performance: sentence plausibility and spatial arrangement. Sentence plausibility, that is to say, the liability of two given nouns in a sentence to act as agent and recipient according to normal subjects' expectancies, had a significant effect on the frequency of correct responses of Broca's aphasics but not on those of Wernicke's. Conversely, the latter were found to be more sensitive to a match or mismatch in the left-to-right spatial arrangement of the grammatical subject and object in a sentence on the one hand, and the order of the corresponding personages in the picture on the other. The results are discussed in terms of “frame selection” and the handling of ordered structure strategies contributing to normal system, but selectively disturbed in the case of brain damage.