Doctoral Dissertations

Date of Award

5-2000

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Speech and Hearing Science

Major Professor

James W. Thelin

Committee Members

Samuel Burchfield, Mark Hedrick, Michael Sims

Abstract

The purpose of this study was to determine the effects of listening task difficulty on attentional effort for normal hearing and hearing impaired individuals. The study utilized a dual-task paradigm involving an auditory task (primary task) of listening to speech in noise and a memory task (secondary task) of digit recall. The memory task was used to measure changes in attentional effort as the difficulty of the auditory task was changed.

The results of the study identified two main strategies for listening to speech in noise. The attentional effort strategy used by most subjects in this study was one of borrowing from the memory task as the auditory task became more difficult. The second attentional effort strategy used by a minority of subjects in this study was one of minimal borrowing from the memory task as the auditory task became more difficult. The group using the minimal borrowing strategy only demonstrated borrowing at the easiest auditory task condition. They did not show an increase in attentional effort as the task became more difficult.

Within the two main strategies, three sub-strategies were found to be used when the auditory task became very difficult or impossible. At this point, the majority of those using the borrowing strategy decreased attentional effort to the auditory task. This sub-strategy was labeled as punting. About one-third of those using the borrowing strategy continued to increase attentional effort to the auditory task, even when the auditory task became impossible. This sub-strategy was labeled as trying. One minimal borrowing subject used the punting sub-strategy when the auditory task became impossible. One minimal borrowing subject did not increase attentional effort to the auditory task at any difficulty level. This sub-strategy was labeled as constant attention to memory.

Hearing impaired and normal hearing subjects were about equally likely to use the borrowing strategy. Hearing impaired subjects were slightly more likely to use the punting sub-strategy.

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