Categorical perception of [ba] and [pa]: Integration of acoustical cues

Abstract

Multiple acoustical cues contribute to the perceptual distinction of many phonetic contrasts. For example, the basic and dominant phonetic correlate of the phonemic (voiced) contrast in stop consonants in word-initial position is the duration of voice onset time (VOT). However, as analysis of production data shows, voiced and voiceless stop consonants vary also in the intensity of a noise burst. The reported study focused on changes in the categorical perception of initial stop consonants [ba] and [pa]. Twenty-eight young adults with normal hearing (better than 10 dB HL) participated in the experiment. Ninety-nine syllables ranging from [ba] to [pa], and which varied in both the VOT and intensity of initial burst, were synthesized on a NEXT computer. Participants were asked to categorize 792 tokens into [ba] and [pa] categories. Results indicate that listeners relied on available cues in different ways. Thus listeners could be divided into two groups: those who used the intensity of burst in their categorization and those who relied exclusively on VOT. Those who integrated information about both acoustical cues did so especially within the ambiguity range.