Sentence Comprehension Deficits: Independence and Interaction of Syntax, Semantics, and Working Memory: Randi C. Martin and Michelle Miller
Findings during the 1970s demonstrated impaired sentence comprehension in aphasic patients who had good single word comprehension (for example, Caramazza & Zurif, 1976; von Stockert & Bader, 1976). For example, a patient might understand the meanings of girl, boy, kiss, red, and hair, but be unable to determine for a sentence such as "The boy that the girl kissed had red hair" who is doing the kissing and who has red hair. Difficulties in establishing the roles played by nouns based on syntactic structure were found even for simple active and passive sentences such as "The cat was chasing the dog" or "The dog was chased by the cat" (Schwartz, Saffran, & Marin, 1980). These sentences are termed reversible, since either noun can play the role of agent (that is, person carrying out the action) or theme (that is, person or object being acted upon). The same patients did not have difficulty understanding sentences with similar structures that were nonreversible, such as "The car that the woman drove was an import" or "The apple was eaten by the boy." Thus, the patients were able to integrate word meanings into a sentence meaning when such could be done on the basis of semantic plausibility but were impaired when they had to use syntactic structure to understand the relations in the sentence. These findings generated a good deal of excitement among researchers in and outside the field of aphasia because they seemed to provide strong evidence for the disruption of a syntactic processing module that was independent of semantics (for example, see Caramazza & Berndt, 1978, Jackendoff, 1993, chap. 11). However, since these early studies, additional results have complicated the interpretation of these findings and their implications for sentence processing.