Two experiments were conducted to determine whether visual speech presented in the visual periphery affects the perceived identity of speech sounds. Auditory speech targets (vCv syllables) were presented in noise (-8 dB) with congruent or incongruent visual speech presented in full-face or upper-half face conditions. Participants' eye-movements were monitored to assure that visual speech input occurred only from the periphery. In Experiment 1 participants had only to identify what they heard. The results showed that peripherally presented visual speech (full-face) facilitated identification of AV congruent stimuli compared to the upper-face control. Likewise, visual speech reduced correct identification for the incongruent stimuli. Experiment 2 was the same as the first except that in addition participants performed a central visual task. Once again significant effects of visual speech were found. These results show that peripheral visual speech affects speech recognition.
Bibliographic reference. Kim, Jeesun / Davis, Chris (2011): "Auditory speech processing is affected by visual speech in the periphery", In INTERSPEECH-2011, 2465-2468.