Blind People Hear Better: Truth or Myth?

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A popular perception holds that blind people have a highly developed sense of hearing. As the thinking goes, our five senses work in concert with one another such that the loss of one is compensated by increased sensitivity in the remaining four.

Generally speaking, the idea springs from one part assumption, one part anecdotal evidence, and perhaps one small part guilt: We like to think those who lack a sense that so richly informs our lives are able to make up the difference.

We further embrace the notion that some blind people can parlay a tragic handicap into a distinct advantage. After all, blind musicians like Stevie Wonder and vocal legend Andrea Bocelli exhibit exceptional musical skill and have what fellow musicians would call "a great ear."

Until recently, there had been little scientific evidence that blind people really do benefit from sensory compensation. At the Montreal Neurological Institute of Canada's McGill University, graduate students working under the tutelage of Robert Zatorre, Ph.D., a neuroscientist and experimental psychologist, put popular perceptions to the test. Their results confirmed expectations—and also yielded some exciting surprises.

Testing 1-2-3

The study began simply enough, with groups of blind and sighted subjects alike tested on pitch perception (how high or low a note is) and position perception (where in space a sound is located). In line with expectations, blind subjects scored better than their sighted counterparts.

However, an unforeseen observation arose: The people who had been blind since birth were the ones who scored best. In fact, the scores correlated directly to the point in life at which each subject lost his or her eyesight. Those born blind had the best performance, followed by subjects who became blind at age four or five. Among those blinded at 10 years old or later, there was little to no difference at all compared to the sighted group.

"What this tells us is that there is plasticity in the brain," says Dr. Zatorre. "That is, when we're young we can actually change around the way neurons work, and reorganize brain function to suit our survival needs. But as we get older, the brain becomes more or less fixed in terms of sensory perception."

In a second test, subjects had one ear plugged and were then asked to locate where sounds were coming from in a room with hidden speakers. Knowing that the brain compares input from both ears to locate sound, the researchers didn't expect anyone to score highly. Yet, half of the blind people scored with impressive accuracy.

These results are probably the best evidence of one sense being compensated by another. Zatorre believes that the blind people who scored well were gleaning highly specific location information from the sound as it was bouncing off of their outer ears. While the cartilage in everyone's outer ear has a unique topography of bumps, grooves, and dents, these subjects were using the ear's features to far greater effect. The sound was there for all to hear, but these subjects had become extremely sensitive to the information it provided.

A startling discovery

The biggest surprise came when the researchers used a PET scan (positron emission tomography), which can indicate brain activity as someone performs various tasks. Zatorre's team, led by then-doctoral student Frédéric Gougoux, knew every subject would show activity in the auditory cortex since that's where the brain processes sound. But for some subjects, the PET revealed activity in the visual cortex, where the brain processes sight. The people with visual activity, it turned out, were the same ones who had shown that particular ability to locate sound with one ear blocked.

"We learned that the part of the brain that normally handles vision does not just die or atrophy without input," says Zatorre. "It somehow adds functionality to process subtle auditory information."

No guarantees

The startling PET-scan results are a testament to the incredible adaptive abilities of the brain. It can practically be rewired in our earliest years, and areas of the brain previously understood to have discrete functions can sometimes be recruited to help accommodate a loss.

Is it reasonable to say that some blind musicians benefit from better hearing? Arguably, heightened pitch perception and spatial location skills would improve a musician's ability to play in tune and perform with other instrumentalists, so they'd have a good head start. But don't romanticize it. Blindness is no guarantee of increased auditory perception, let alone musical ability, and by far the vast majority of musical geniuses are lucky enough to have all of their senses intact.

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Rich Maloof's award-winning writing has covered subjects ranging from soda pop to stem cells. He has written for MSN, CNN, MSNBC, Yahoo!, Women’s Health, and various other publications. He is the published author of 12 books to date, including several instructional titles for musicians. His latest title, This Will Kill You, is being released by St. Martin's Press in May. Rich is a regular contributor to Brain & Body.