Dichotic masking of consonants by vowels.

Abstract

The dichotic masking effects of a vowel (/a/) on CV syllables (stop + /a/) were investigated by comparing the effect of CV masks with (a) the effect of CV masks in which the vowel was shortened and (b) the effect of an isolated vowel mask. The vowel exerted a clear masking effect, both when isolated and when in CV context, but this effect was much less pronounced than the ’’masking’’ produced by a competing consonant. It was hypothesized that consonants exert their ’’masking’’ effect on consonant (CV) targets at a central (phonetic) level, while vowel masking is largely a ’’peripheral’’ (auditory) phenomenon. Detailed analysis of the vowel masking effect revealed several distinct components. The two most interesting effects were (a) a relationship between stimulus onset asynchrony and the probability of voiced responses, which was interpreted as masking and substitution of the cue of voice onset time, and (b) a relationship between the pitch contour of the vowel mask and the probability of a voiced response, which suggested that the pitch contour of an isolated vowel may act as a voicing cue when paired with a consonant in the other ear. While all these effects were interpreted as consequences of relatively peripheral binaural mixing, the possibility that part of the vowel masking effect occurred at a later, phonetic processing stage could not be excluded. Subject Classification: 70.30.