Allen P, Wightman F
Waisman Center for Mental Retardation and Human Development University of Wisconsin, Madison.
J Speech Hear Res. 1994 Feb;37(1):205-15. doi: 10.1044/jshr.3701.205.
This article reports the results of an experiment that used a two-alternative forced-choice task to measure the ability of 3- to 5-year-old children to detect 501 Hz, 1000 Hz, and 2818 Hz sinusoids in noise. Psychometric functions were fit to each individual's data, and thresholds (signal level required for 75% correct) were interpolated from the fitted functions. Results showed that, on average, the children's thresholds were higher and the slopes of their psychometric functions were shallower than those of the adults. However, the between-subjects variability in the children's data was large, and the performance of many individual children was not well described by group mean performance. One-third of the children produced thresholds that were elevated by an average of 10 dB but psychometric function slopes that were adult-like. Another one-third of the children produced thresholds that were elevated relative to those of the adults by an average of 20 dB and psychometric function slopes that were very shallow. The data from a smaller group of children showed large variability in psychometric function slope and threshold, and for a very few children performance was at chance regardless of the signal level. A replication of the study several months later showed that for most listeners the individual patterns of performance persisted over time.
