Effects of Signal and Masker Uncertainty on Children’s Detection This paper reports the results of two experiments that examined the effects of signal and masker uncertainty on preschool-age children’s and adults’ detection of tonal signals in noise maskers. In Experiment 1 (signal uncertainty) the signal was randomly at 501 or 2818 Hz. The majority of the adult listeners showed ... Research Article
Research Article  |   April 01, 1995
Effects of Signal and Masker Uncertainty on Children’s Detection
 
Author Affiliations & Notes
  • Prudence Allen
    Waisman Center for Mental Retardation and Human Development University of Wisconsin-Madison
  • Frederic Wightman
    Waisman Center for Mental Retardation and Human Development University of Wisconsin-Madison
  • Currently affiliated with the University of Western Ontario
    Currently affiliated with the University of Western Ontario×
  • Contact author: Prudence Allen, PhD, the University of Western Ontario, Department of Communicative Disorders, Elborn College, London, Ontario, Canada N6G 1H1.
    Contact author: Prudence Allen, PhD, the University of Western Ontario, Department of Communicative Disorders, Elborn College, London, Ontario, Canada N6G 1H1.×
Article Information
Hearing & Speech Perception / Acoustics / Research Issues, Methods & Evidence-Based Practice / Hearing / Research Articles
Research Article   |   April 01, 1995
Effects of Signal and Masker Uncertainty on Children’s Detection
Journal of Speech, Language, and Hearing Research, April 1995, Vol. 38, 503-511. doi:10.1044/jshr.3802.503
History: Received December 8, 1993 , Accepted November 29, 1994
 
Journal of Speech, Language, and Hearing Research, April 1995, Vol. 38, 503-511. doi:10.1044/jshr.3802.503
History: Received December 8, 1993; Accepted November 29, 1994

This paper reports the results of two experiments that examined the effects of signal and masker uncertainty on preschool-age children’s and adults’ detection of tonal signals in noise maskers. In Experiment 1 (signal uncertainty) the signal was randomly at 501 or 2818 Hz. The majority of the adult listeners showed a slight decrement in performance consistent with an ability to monitor both frequencies simultaneously. The majority of the children, however, showed no decrement in performance, suggesting that the children may not have focused attention at the signal frequency even when it was fixed. In Experiment 2 (masker uncertainty), random-frequency, random-level, tonal distracters were added to each interval of the 2 alternative-forced-choice (2afc) procedure. The effect of masker uncertainty was much larger than that of signal uncertainty. For most of the adult listeners and some of the children, the distracters produced higher thresholds (on average by 10 dB) and shallower psychometric function slopes. For most of the children, thresholds increased by 20 dB or more and psychometric functions were often nearly flat.

This paper reports the results of two experiments that examined the effects of signal and masker uncertainty on preschool-age children's and adults' detection of tonal signals in noise maskers. In Experiment 1 (signal uncertainty) the signal was randomly at 501 or 2818 Hz. The majority of the adult listeners showed a slight decrement in performance consistent with an ability to monitor both frequencies simultaneously. The majority of the children, however, showed no decrement in performance, suggesting that the children may not have focused attention at the signal frequency even when it was fixed. In Experiment 2 (masker uncertainty), random-frequency, random-level, tonal distracters were added to each interval of the 2 alternative-forced-choice (2afc) procedure. The effect of masker uncertainty was much larger than that of signal uncertainty. For most of the adult listeners and some of the children, the distracters produced higher thresholds (on average by 10 dB) and shallower psychometric function slopes. For most of the children, thresholds increased by 20 dB or more and psychometric functions were often nearly flat.

Acknowledgments
The authors gratefully acknowledge the contributions of Mary Bolger, Patricia Heagle, Lawrence Lalone, Patricia Lea, Douglas Swiggum, and the children and teachers of the Waisman Early Childhood Program for their contributions to the research; Terrence Dolan, Doris Kistler, and Robert Lutfi for their helpful comments; and the National Institute of Child Health and Human Development (R01-HD-23333) for financial support.
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