Auditory and Visual Contributions to the Perception of Consonants

Abstract

Perceptual confusions of 16 consonant-vowel (CV) syllables were studied with normal-hearing adults under conditions of auditory-visual presentation at various signal-to-noise (S/N) ratios, as well as under auditory-only and visual-only conditions in quiet. An articulatory feature classification system was used to analyze responses with regard to percentage correct intelligibility and relative information transmission. In the auditory conditions, features of voicing and nasality were least affected by noise, while place of articulation showed the greatest reduction in intelligibility. The auditory-visual confusions indicated that the visual channel in bisensory presentations reduced errors when phonemes differed by place of articulation, with the greatest visual complement occurring at the poorer S/N ratios. Responses from the visual-only condition indicated that the subjects were able to categorize the phonemes into discrete homophenous groups. Part-whole reliability for the visual-only condition was high, indicating that a short form of the test could be used for screening aural-rehabilitation clients. Finally, since the subjects' ability to visually recognize five places of articulation was nearly perfect, it was suggested that emphasis in aural rehabilitation be placed on auditory training or use of contextual cues, rather than on lipreading.