Language-General Auditory-Visual Speech Perception: Thai-English and Japanese-English McGurk Effects

Area of Science:

• Psycholinguistics
• Auditory Perception
• Speech Science

Background:

• The McGurk effect reveals audiovisual speech integration.
• Cross-language variations in phonotactics and phoneme inventories may influence speech perception.

Purpose of the Study:

• To investigate the locus of auditory-visual speech integration using cross-language McGurk effects.
• To determine if native language phonotactics and phonemic biases affect audiovisual speech perception.

Main Methods:

• Experiment 1: Tested English and Thai speakers on /m/-/n/ perception using auditory [m]/visual [] stimuli in word-initial and -final positions.
• Experiment 2: Tested English and Japanese speakers on /d/-/ð/ perception using auditory [b]/visual [g] stimuli with varying vowel contexts and speaker languages.

Main Results:

• Experiment 1: No significant difference in /n/ perception between English and Thai speakers, regardless of position.
• Experiment 2: All groups showed a phonetic-level interaction between vowel context and /d/ vs. /ð/ responses, irrespective of native language.
• Audiovisual speech integration appears to occur at a phonetic level, with post-categorical influences.

Conclusions:

• Auditory-visual speech information is integrated at a phonetic level.
• Native language biases have limited impact on phonetic-level audiovisual speech integration.
• A phonetic plus postcategorical model explains cross-language McGurk effects.