Monaural temporal integration and temporally selective listening in children and adults

Abstract

This study used two paradigms to investigate the development of temporal integration and temporally selective listening. Experiment 1 measured detection as a function of duration for a pure tone at 1625 or 6500 Hz. At both frequencies thresholds of children younger than 7 years old were higher than those for older children and adults. The pattern of temporal integration was similar across groups for the 6500-Hz signal, but younger children showed relatively more temporal integration for the 1625-Hz signal due to high thresholds for the briefest 1625-Hz signal. Experiment 2 measured detection thresholds for one or for three brief tone pips presented in a noise masker. In one set of conditions, the noise masker consisted of 100-ms steady bursts interleaved with 10-ms temporal gaps. In other conditions, the level of the central 50 ms of the 100-ms masking noise bursts was adjusted by either +6 or -6 dB. Children showed higher thresholds but similar temporal integration compared with adults. Overall, these data suggest that children are less efficient than adults in weighting the output of the monaural temporal window at 1625 but not 6500 Hz. Children are efficient in combining energy from brief temporal epochs that are separated by noise.

Figure 1

Mean thresholds (dB SPL) measured at different durations, plotted separately for adults and children, as indicated in the legend. Error bars show ± one standard error. The filled circles show data of younger children, open circles show data for older children, and the open squares the data of adults. The left panel shows results at 6500 Hz, and the right panel shows results at 1625 Hz.

Figure 2

Individual child thresholds in select conditions are plotted as a function of listener age, along with the associated mean adult threshold. Results for the 6500-Hz signal frequency are shown in the left panel, and those for the 1625-Hz signal are show in the right panel. As indicated in the legend associated with each panel, down-pointing triangles show thresholds for the shortest signal duration, and up-pointing triangles show those for the longest signal duration.

Figure 3

Schematic representation of the stimuli for the −6-dB level transition condition.

Figure 4

Mean thresholds (dB SPL) measured for three level transition conditions, plotted separately for the two signal conditions (one pip and three pips). Error bars show ± one standard error of the mean. Circles show thresholds for three pips and triangles show thresholds for one-pip conditions. The left panel shows the results of the adults, the middle panel shows results of the children older than 7 years, and the right panel shows the results of the children younger than 7 years.

Figure 5

Mean temporal integration (dB) calculated for three level transition conditions plotted separately for the two subject groups, as indicated in the legend. Error bars show ± one standard error of the mean.