Abstract:
The study focused on changes in the categorical perception of intial stop consonants as a function of age and hearing status. The identification of intial stop consonants differing in voicing and place of articulation relies on an integration of multiple acoustic cues (VOT, character of the noise burst, onset frequency and direction of the second and third formant transitions). Four hundred subjects, divided into four age groups (20--85 years) and into three hearing groups, participated in experiments that required the identification of syllables [ba] or [pa] and [ba], [da], or [ga] along synthesized continua. Stimuli were presented to subjects via headphones at 75 dB SPL. Results demonstrated that the phonemic boundary of the [ba--pa] continuum was shifted towards a longer VOT as a function of age and hearing status. Moreover, the phonemic boundaries between [ba] and [da], and between [da] and [ga], demonstrated by older and hearing impaired subjects were shifted toward [d] and [g] categories as compared to young subjects with normal hearing. The observed changes may be due to the age-related deterioration of ability to analyze brief signals and ability to integrate multiple acoustical cues. [Work supported by Health and Welfare of Canada.]