Development and the role of internal noise in detection and discrimination thresholds with narrow band stimuli.
The experiments reported here examine the role of internal noise in the detection of a tone in narrow band noise and intensity discrimination for narrow band stimuli in school-aged children as compared to adults. Experiment 1 used 20-Hz wide bands of Gaussian and low-fluctuation noise centered at 500 Hz to assess the role of stimulus fluctuation in detection of a 500-Hz pure tone. Additional conditions tested whether performance was based on level and/or level-independent cues. Children's thresholds were elevated with respect to adults, and whereas adults benefited from the reduced fluctuation of low-fluctuation noise, children did not. Results from both groups were consistent with the use of a level cue. Experiment 2 estimated intensity increment thresholds for a narrow band Gaussian noise or a pure tone, either with or without a presentation-by-presentation level rove, an additional source of level variability. Stimulus variability was found to have a larger effect on performance of adults as compared to children, a rather counterintuitive finding if one thinks of children as more prone to informational masking introduced by stimulus variability. Both tone-in-noise and intensity discrimination data were consistent with the hypothesis that children's performance is limited by greater levels of internal noise.
Buss
Emily
E
Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA. ebuss@med.unc.edu
Hall
Joseph W
JW
Grose
John H
JH
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D016011:Normal Distribution; D010470:Perceptual Masking / Q000502:physiology*