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

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.

Imitation of intonation by infants.

Children between 9 and 12 months of age were studied to determine if they would spontaneously imitate either the average fundamental frequency or the fundamental frequency contour of their speaking partners. In the first experiment, children were recorded at home as they interacted with their fathers and mothers. Acoustic analyses failed to reveal any tendency on the part of the infants to adjust vocal pitch, amplitude, or duration to those of their speaking partners. In a second experiment, children were recorded while interacting with their parents in a laboratory setting. Again, there were no indications that the children imitated the vocal patterns of their speaking partners.