Auditory-Visual Speech Processing
The McGurk illusory percept is obtained by dubbing an incongruent articulatory movement onto an auditory signal. The Mismatch Negativity (MMN) of the auditory Event-Related Potential (ERP) reflects the detection of a deviant stimulus within auditory short-term memory (STM) and besides an acoustic component, possesses, under certain conditions, a phonetic one. The present study assessed the existence of an MMN evoked by McGurk percepts. Three experimental conditions were investigated: auditory alone, visual alone and audiovisual (all with the same auditory components). The auditory deviant syllables and the audiovisual incongruent syllables elicited a significant MMN. In the visual condition, no negativity was observed. An MMN can be evoked by audiovisual stimuli that are deviant by their visual content only, provided they are presented in a suitable auditory context leading to a phonetically significant interaction.
Bibliographic reference. Colin, C. / Radeau, M. / Deltenre, P. (2001): "The mismatch negativity (MMN) and the McGurk effect", In AVSP-2001, 56-61.