Comodulation detection differences in children and adults.

This study investigated comodulation detection differences (CDD) in children (ages 4.8-10.1 years) and adults. The signal was 30-Hz wide band of noise centered on 2 kHz, and the masker consisted of six 30-Hz wide bands of noise spanning center frequencies from 870 to 4160 Hz. The envelopes of the masking bands were always comodulated, and the envelope of the signal was either comodulated or random with respect to the masker. In some conditions, the maskers were gated on prior to the signal in order to minimize effects related to perceptual fusion of the signal and masker. CDD was computed as the difference between signal detection thresholds in conditions where all bands were comodulated and conditions where the envelope of the signal was random with respect to the envelopes of the maskers. Values of CDD were generally small in children compared to adults. In contrast, masking release related to masker/signal onset asynchrony was comparable across age groups. The small CDDs in children are discussed in terms of sensitivity to comodulation as a perceptual fusion cue and informational masking associated with the detection of a signal in a complex background, an effect that is ameliorated by asynchronous onset.