First Advisor

James F. Maurer

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Speech Communication


Speech Communication




Intelligibility of Speech, Noise -- Psychological aspects



Physical Description

1 online resource (58 p.)


The purpose of this investigation was to measure the ability of young normal hearing listeners to perceive speech in the presence of a background noise which varies in the relative intensity of its semantic content. The Speech Perception in Noise test was mixed with a two-component competing noise complex in which the narrative-to- speech noise ratio varied in 2 dB increments from -2 dB Na/SpN to +8 dB Na/SpN. These stimuli were presented at an overall +8 dB signal-to-noise ratio to thirty young normal hearing adults through the soundfield system. The differences between the mean error scores and standard deviations for the low predictability sentences were found to be statistically significant at all Na/SpN ratios. No main effect was observed for the Na/SpN ratios on the high predictability sentences. Significant differences were also observed between the mean error scores and standard deviations of HP and LP pairs at each Na/SpN ratio. These data further revealed a systematic increase in LP mean error scores and standard deviations as a result of linear increases in the Na/SpN ratio. These results suggest that semantically loaded competing noise significantly influences the perception of primary messages as a direct function of the competition ratio.


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