Non-Sensory factors in children's speech perception

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DESCRIPTION (provided by applicant): The overall goal of this project is to investigate non-sensory influences in child speech perception, specifically the impact of stimulus repetition in a discrimination task. The need for speech perception testing in children has increased dramatically with the evaluation of the efficacy of hearing aids and cochlear implants. Many current tests assess word recognition only and fail to separate speech perception ability from vocabulary. The Change/No-Change procedure (Sussman & Carney, 1989) assesses speech discrimination with standard and comparison stimuli during change trials (standard and comparison differ) and no-change trials (standard and comparison are the same). Response bias, a non-sensory influence on performance, is evaluated by scoring hits and correct rejections. The multiple looks hypothesis (Viemeister & Wakefield, 1991) predicts that discrimination performance increases with increases in the number of standard and comparison stimuli, despite the fact that no new sensory information is provided. Questions related to the multiple looks hypothesis remain, including: whether performance varies with different numbers of presentations of stimuli and what developmental issues are relevant to the procedure. To address these issues, the Change/No-Change procedure will be used with normal-hearing adults and children using three pairs of stimuli and various numbers of standard and comparison stimuli. We hypothesize that performance will improve with increased total number of "looks" at the stimuli, the number of standards will be more important than the number of comparisons, the number of presentations of stimuli will be more beneficial to child than adult participants, and that we will be able to assess the impact of two non-sensory factors, response bias and multiple looks at the stimuli, on child speech perception.