Forward and Backward Masking of Consonants in School-Age Children and Adults

Abstract

Purpose This experiment sought to determine whether children's increased susceptibility to nonsimultaneous masking, particularly backward masking, is evident for speech stimuli. Method Five- to 9-year-olds and adults with normal hearing heard nonsense consonant–vowel–consonant targets. In Experiments 1 and 2, those targets were presented between two 250-ms segments of 70-dB-SPL speech-shaped noise, at either −30 dB signal-to-noise ratio (Experiment 1) or at the listener's word recognition threshold (Experiment 2). In Experiment 3, the target was presented in steady speech-shaped noise at listener threshold. For all experiments, percent correct was estimated for initial and final consonants. Results In the nonsimultaneous noise conditions, child–adult differences were larger for the final consonant than the initial consonant whether listeners were tested at −30 dB signal-to-noise ratio (Experiment 1) or at their individual word recognition threshold (Experiment 2). Children were not particularly susceptible to backward masking relative to adults when tested in a steady masker (Experiment 3). Conclusions Child–adult differences were greater for backward than forward masking for speech in a nonsimultaneous noise masker, as observed in previous psychophysical studies using tonal stimuli. Children's greater susceptibility to nonsimultaneous masking, and backward masking in particular, could play a role in their limited ability to benefit from masker envelope modulation when recognizing masked speech.