Joan Raymond writes: Have you ever taken off your glasses only to discover that besides being blind as bat, you can’t hear too well either? You’re not alone. There’s even a small cadre of Facebook folks who gather under the group, "I can't hear you, I don't have my glasses on."
According to Lawrence Rosenblum, professor of psychology at the University of California, Riverside, the phenomena – though not highly researched – is plausible. “What we understand about the perceptual brain is that our senses integrate, and though we don’t think we use sight in hearing, we lip-read all the time,” and also get clues from teeth and tongue movement, says Rosenblum, author of "See What I'm Saying: The Extraordinary Powers of Our Five Senses." So if you can't see with your glasses off, you can't "hear" very well, either.
A phenomenon called The McGurk Effect shows how we all integrate so-called visual speech into speech that we hear. According to Rosenblum, researchers found that when a word or syllable is dubbed on a video showing a person’s face making a different sound, people will usually say the sound they “hear” is what the person on the video is saying, not the sound dubbed over it. Sometimes, people will come up with an entirely new sound, a combination of both the audio and video.
Rosenblum’s own research shows just how tightly sight and hearing are intertwined. In a study published in the journal Attention, Perception and Psychophysics, participants watched people mouth 80 words. The participants all had good hearing and no formal lip-reading training. When they were asked to repeat the word they thought was being said, participants were more likely to repeat the word in the same accent as the person who was mouthing the word. “We all mimic each other,” says Rosenblum, “but what’s so interesting is we do that even if we can only see, not hear, what a person is saying.”