The integration of auditory and visual speech information with foreign speakers: The role of expectancy

It has been found that auditory-visual integration in the McGurk effect is affected by the relationship between the language of the speaker and that of the perceiver: for a foreign speaker, perceivers tend to incorporate visual information to a greater extent. We investigated whether this is due to the perceivers’ detection of the speech sounds as foreign or to an expectancy based upon the appearance of the speaker. English, Japanese, Cantonese, and Thai subjects were presented with English, Japanese, Cantonese, and Thai speakers in a condition in which an expectancy was set (trials blocked by speaker language) or in a random trials condition. There were indeed foreign language effects, albeit in the opposite direction to that expected, and these occurred mainly as the results of expectancies based on the appearance of the speaker rather than the perceived deviation of foreign speech sounds from native language prototypes.