New Study can the Eyes Play Tricks on the Ears

Is seeing believing? Researchers from the University of Chicago say that, in certain situations, it indeed can be. There, a new study was published on December 20, 2007 which identified the regions of the brain that are responsible for tricking our ears on a daily basis.

In conversation, people generally identify spoken words from the sounds that are heard. However, what many people don’t realize is, our brains interpret speech by by both what we hear and what we see.

For instance, imagine a conversation in a crowded, noisy restaurant. When the waiter appears at the table to take the order, he asks, “What can I get for you this evening?” The noise of the other customers laughing and talking, combined with dishes clanking and cooks shouting, make his words hard to distinguish.

At a time like this one, most people are drawn to the waiter’s mouth in an attempt to read his lips to determine what he is saying. It is in this situation, or others like it, that our eyes can deceive us.

“As an example, what would happen if a person’s voice says ‘pa,’ but the person’s lips mouth the word ‘ka?’ One would think you might hear ‘pa’ because that is what was said. But in fact, with the conflicting verbal and visual signals, the brain is far more likely to hear ‘ta,’ an entirely new sound,” explains Uri Hasson, scholar at the University of Chicago’s Neuroscience Laboratory. “When speech sounds do not correspond exactly to the words that are mouthed, the brain often conjures a third sound as an experience-and this experience may often vary from what was actually spoken.”

So, while the waiter says one thing, our eyes tell us what we see the waiter say, and our ears tell us what we hear the waiter say, our brains might interpret something completely different from both.

When coping with hearing loss, this phenomenon, called the McGurk effect, plays a major part in the interpretations that our brains make of spoken word. The effect proves that we can’t always believe what our ears tell us we hear, especially at times when we can see the speaker’s face. Leading to the conclusion that, sometimes we are better off not looking at a speaker at all.

Want to test the theory? Visit this interesting web page: http://homepage.ntu.edu.tw/~karchung/Phonetics%20II%20page%20seventeen.htm