ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
2pSC6. The effect of face and lip inversion on audiovisual speech
integration.
Deborah A. Yakel
Lawrence D. Rosenblum
Dept. of Psychol., Univ. of California, Riverside, Riverside, CA 92521
Kerry P. Green
Univ. of Arizona
Chantel L. Bosley
Rebecca A. Vasquez
Univ. of California, Riverside, Riverside, CA 92521
Seeing a speaking face can influence observers' auditory perception of
syllables [McGurk and McDonald, Nature 264, 746--748 (1976)]. This effect
decreases when the speaker's face is inverted [e.g., Green, 3014
(1994)]. Face recognition is also inhibited with inverted faces [e.g., Rock,
Sci. Am. 230, 78--85 (1974)] suggesting a similar underlying process. To
further explore the link between face and audiovisual speech perception, a
speech experiment was designed to replicate another face perception effect. In
this effect, an inverted face and an inverted face containing upright lips are
perceived as looking normal, but an upright face with inverted lips looks
grotesque [Thompson, Perception 9, 438--484 (1980)]. An audiovisual speech
experiment tested four presentation conditions: Upright face-upright mouth,
upright face-inverted mouth, inverted face-inverted mouth, inverted
face-upright mouth. Various discrepant audiovisual syllables were tested in
each condition. Visual influences occurred in all but the upright face-inverted
mouth condition for some of the syllable combinations thereby mimicking the
face perception effect. However, other syllable combinations revealed visual
influences in all four conditions. Results are interpreted in terms of
articulatory dynamics and the vertical symmetry of the visual stimuli.