Audiovisual integration in dichotic listening

The presentation of visual stimuli of moving mouth is known to affect the phoneme perception of the auditory stimuli during natural speech, and provides important insights into the scientific and technological study of speech. In order to investigate the laterality of the audiovisual integration we studied the relationship between the McGurk effect (McGurk and McDonaold 1976) and Right Ear Advantage (REA) in dichotic listening (DL). When visual /ga/ was presented with the dichotic auditory stimuli, both the McGurk effect and REA was observed. On the other hand, when visual /ba/ was paired with the dichotic auditory stimuli, the visual /ba/ strongly affected the proportion of the phoneme perceived. In addition, the phoneme perception in the DL was influenced by the auditory syllables fed into the right ear more than those fed into the left ear. These results suggest that the cortical processes that underlie the McGurk effect is consistent with, and probably shares the same process with, those that lead to REA.