Don’t Listen With Your Mouth Full: The Role of Facial Motor Action in Visual Speech Perception

Abstract

Theories of speech perception agree that visual input enhances the understanding of speech but disagree on whether physically mimicking the speaker improves understanding. This study investigated whether facial motor mimicry facilitates visual speech perception by testing whether blocking facial motor action impairs speechreading performance. Thirty-five typically developing children (19 boys; 16 girls; M age = 7 years) completed the Revised Craig Lipreading Inventory under two conditions. While observing silent videos of 15 words being spoken, participants either held a tongue depressor horizontally with their teeth (blocking facial motor action) or squeezed a ball with one hand (allowing facial motor action). As hypothesized, blocking motor action resulted in fewer correctly understood words than that of the control task. The results suggest that facial mimicry or other methods of facial action support visual speech perception in children. Future studies on the impact of motor action on the typical and atypical development of speech perception are warranted.