UBC Theses and Dissertations
The effects of context on speech understanding in noise Howarth, Tanis Marie
Twelve normal-hearing subjects (22 to 29 years) listened to passages of text in the presence of a twelve-speaker babble background noise. The passages were presented in a line-by-line fashion and subjects were asked to repeat each line as accurately as they could. The present study investigated whether three text types differing in macrostructure (narrative, descriptive, and procedural) would differentially effect how speech is perceived in the presence of background noise. Also, the number and types of errors (deletions, additions, substitutions, and exchanges) that occurred as signal-to-noise conditions decreased from 0dB to -12dB were examined. The degree to which a subject's response matched the target at three linguistic levels (auditory, syntactic, and semantic) was analyzed as either a partial match, total match, or no match at all. It was found that when listening to narratives, significantly fewer errors were made than when listening to descriptions. It was also shown that if only the number of auditory errors are counted and used as a means by which to assess the listening abilities of an individual in noise, then the robustness of syntactic and semantic information is not appreciated.
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