Level, spectral and temporal cues in children's detection of masked signals

Résumé

Preschool-aged children and adults detected masked signals in four conditions evaluating the role of level, spectral and temporal cues on performance. Performance was similar in fixed and roving level conditions for both age groups suggesting use of level-invariant cues. When the signal was moved to the spectral edge of the masker the performance of the adults improved but that of the children did not suggesting that the children did not benefit from cues provided by the off-center signal. Children's performance worsened when the signal was a narrow band noise rather than a pure tone but the adults' did not, suggesting children's reliance on temporal changes in the masker with the introduction of the signal. Analyses of the stimuli suggested that the children's thresholds corresponded to signal-to-noise ratios at which multiple cues were present at magnitudes that were large enough to be discriminable. These findings were in agreement with post hoc analyses of tonal signals presented in flat- and notched-spectrum maskers used to examine frequency resolving ability in an earlier study. In that study young children's thresholds were obtained at levels for which level, frequency and periodicity values differed between the signal and no signal stimuli at magnitudes that would be discriminable, independent of the spectral qualities of the masker. [Work supported by NSERC].