Effects of apparent listener knowledge and picture stimuli on aphasic and non-brain-damaged speakers' narrative...

This experiment investigated whether aphasic adults' assumptions regarding listener knowledge of the topic of discourse affects the content of their narrative discourse. Aphasic and non-brain-damaged adults told two stories about sequences of black-and-white line drawings in two conditions. In a knowledgeable listener condition, subjects told the stories to a listener while the subject and listener were looking at the pictures portraying the story. In a naive listener condition, subjects told the stories to a listener whom the subject had not met before, who did not have access to pictures about the stories, and who the subject was led to believe had no knowledge of the pictures upon which the stories were based. The differences in performance between non-brain-damaged and aphasic subjects were greater than the differences between listener conditions and between stories. Non-brain-damaged subjects produced significantly more words, more information, a greater percentage of words that communicated relevant and accurate information, and longer grammatical units than aphasic subjects did. There were no significant differences between non-brain-damaged and aphasic subjects in their use of four kinds of cohesive ties. Listener conditions and stories had few significant effects on non-brain-damaged or aphasic subjects' performance, and the few statistically significant effects that were observed did not appear to be clinically important.