Differential responding to content and intonation components of a complex auditory stimulus by nonverbal and echolalic autistic children

Anecdotal and scientific reports of the speech of autistic children suggest a possible differential responsiveness to limited components of speech stimuli. Previously nonverbal children who acquire speech seem to acquire content, but their speech is dysprosic, characterized by inappropriate intonation, pitch, rhythm, and modulation. In contrast, echolalic autistic children often display modulation and varied intonation but may demonstrate no comprehension of the verbal stimulus being echoed. The present experiment was conducted to systematically determine whether echolalic and nonverbal autistic children respond overselectively to the intonation or to the content of a complex auditory stimulus differing along these two dimensions. Ten autistic children (five echolalic and five nonverbal) and six normal children, matched for MA, were trained to bar press at the sound of an auditory complex stimulus designated as S+ and to withhold response to an auditory complex stimulus designated as S-. The auditory complex stimulus consisted of two components, content and intonation. Test trials consisting of various combinations of the intonation and content components were then presented. Results indicated that whereas the normal children responded to both components or to content, the nonverbal children showed evidence of selectively responding to content, and the echolalic children showed evidence of selectively responding to intonation. These results are discussed in terms of relating autistic stimulus overselectivity to deficits in speech production and to implications for designing language training programs for these children.