Forward and backward masking of consonants in school-age children and adults

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.