title: The effect of lip-reading on primary stream segregation.
abstract: Lip-reading has been shown to improve the intelligibility of speech in multitalker situations, where auditory stream segregation naturally takes place. This study investigated whether the benefit of lip-reading is a result of a primary audiovisual interaction that enhances the obligatory streaming mechanism. Two behavioral experiments were conducted involving sequences of French vowels that alternated in fundamental frequency. In Experiment 1, subjects attempted to identify the order of items in a sequence. In Experiment 2, subjects attempted to detect a disruption to temporal isochrony across alternate items. Both tasks are disrupted by streaming, thus providing a measure of primary or obligatory streaming. Visual lip gestures articulating alternate vowels were synchronized with the auditory sequence. Overall, the results were consistent with the hypothesis that visual lip gestures enhance segregation by affecting primary auditory streaming. Moreover, increases in the naturalness of visual lip gestures and auditory vowels, and corresponding increases in audiovisual congruence may potentially lead to increases in the effect of visual lip gestures on streaming.
authors.affiliation: Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 Université Lyon 1, 69366 Lyon Cedex 07, France.
authors.forename: Aymeric
authors.initials: A
authors.lastname: Devergie
authors.forename: Nicolas
authors.initials: N
authors.lastname: Grimault
authors.forename: Etienne
authors.initials: E
authors.lastname: Gaudrain
authors.forename: Eric W
authors.initials: EW
authors.lastname: Healy
authors.forename: Frédéric
authors.initials: F
authors.lastname: Berthommier
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D003463:Cues; D006801:Humans; D008085:Lipreading; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D010775:Photic Stimulation; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013997:Time Factors; D055815:Young Adult