Visual influences on the perception of alveolar/velar place discrimination

Abstract

Using ten acoustic stimuli ranging along a /ga/–/da/ continuum, visual influences on the psychophysical boundary between the auditory percepts of /ga/ and /da/ were investigated. A significant shift in the perceptual boundary was found depending on whether syllables were dubbed onto a video of a speaker uttering /da/, or whether they were dubbed onto a video of the same speaker uttering /ga/. The tongue of the speaker was not visible in either video clip, so only subtle cues were available to distinguish place of articulation in the two conditions. The shift in auditory perception was in a direction consistent with the visual information, and indicates that even the subtle visual cues available to discriminate velar stop consonants from alveolar stop consonants can play a role in speech perception. The possibility that other (nonarticulatory) visual cues could be conditioned to play a similar role in speech perception is raised.