Do You See What I Am Saying? Exploring Visual Enhancement of Speech Comprehension in Noisy Environments

Viewing a speaker's articulatory movements substantially improves a listener's ability to understand spoken words, especially under noisy environmental conditions. It has been claimed that this gain is most pronounced when auditory input is weakest, an effect that has been related to a well-known principle of multisensory integration--"inverse effectiveness." In keeping with the predictions of this principle, the present study showed substantial gain in multisensory speech enhancement at even the lowest signal-to-noise ratios (SNRs) used (-24 dB), but it was also evident that there was a "special zone" at a more intermediate SNR of -12 dB where multisensory integration was additionally enhanced beyond the…