Hearing Cues Research Articles

Binaural informational masking release in children and adults

Informational masking associated with masker spectral uncertainty can sometimes be reduced by providing cues that promote perceptual segregation of the signal from the masker. Our previous research using the multi-burst-same (MBS) paradigm of Kidd et al. [J. Acoust. Soc. Am. 95, 3475–3480 (1994)] indicated that all adults and most children (5–9 YO) showed reduced informational masking when monaural segregation cues related to gating asynchrony or spectro-temporal coherence were available. The present study examined developmental effects in children aged 6–10 years for release from informational masking in a condition where perceptual segregation was manipulated using a spatial hearing cue. In the informational masking condition, the pure-tone signal and the MBS masker components were presented to the left ear. In the masking release condition, the masker components were also presented to the right ear synchronously (at a level 10-dB higher than in the left ear) so that the signal would be lateralized to the left ear and the masker would be lateralized to the right ear. Results indicated that most adults achieved masking release in this condition, but that none of the children did. These results are consistent with previous findings indicating protracted development for informational masking release related to spatial hearing cues.

Perceiving the stress pattern of words in sentences

The cues for hearing the stress pattern of a word may be different depending on whether the word occurs in isolation or in a sentence. Furthermore, even within a sentence, the relative importance of the cues depends upon where the word occurs in the sentence, and upon phrasal accent. For example, contrary to Fry's classic results with words in isolation, the pitch contour was useless as a cue for perceiving the stress pattern of a noun preceded by an accented adjective. The word's duration pattern proved a more robust cue than pitch for stress pattern perception; the word's amplitude contour was useless as a cue. These results derive from an experiment where listeners had to identify the stress pattern of bisyllabic nonsense words embedded in meaningful sentences. The listeners had only to choose between the nonsense words “MAma” and “maMA” (10 and 01 stress patterns, respectively) on the basis of the perceived stress pattern. The duration, fundamental frequency, amplitude and spectral features of the nonsense words were manipulated factorially via LPC analysis-synthesis to assess the relative importance of these acoustic features as cues for stress perception.