http://feedproxy.google.com/~r/bookofjoe/~3/gf7_2XxHaJI/the-blind-man-who-taught-himself-to-see.html
via Byline
[image: M203bata]
Excerpts from Michael Finkel's March 2011 Men's Journal article
Daniel Kish has been sightless since he was a year old. Yet he can mountain bike. And navigate the wilderness alone. And recognize a building as far away as 1,000 feet. How? The same way bats can see in the dark.
The first thing Daniel Kish does, when I pull up to his tidy gray bungalow in Long Beach, California, is make fun of my driving. “You’re going to leave it that far from the curb?” he asks. He’s standing on his stoop, a good 10 paces from my car. I glance behind me as I walk up to him. I am, indeed, parked about a foot and a half from the curb.
The second thing Kish does, in his living room a few minutes later, is remove his prosthetic eyeballs. He does this casually, like a person taking off a smudged pair of glasses. The prosthetics are thin convex shells, made of acrylic plastic, with light brown irises. A couple of times a day they need to be cleaned. “They get gummy,” he explains. Behind them is mostly scar tissue. He wipes them gently with a white cloth and places them back in.
Kish was born with an aggressive form of cancer called retinoblastoma, which attacks the retinas. To save his life, both of his eyes were removed by the time he was 13 months old. Since his infancy — Kish is now 44 — he has been adapting to his blindness in such remarkable ways that some people have wondered if he’s playing a grand practical joke. But Kish, I can confirm, is completely blind.
He knew my car was poorly parked because he produced a brief, sharp click with his tongue. The sound waves he created traveled at a speed of more than 1,000 feet per second, bounced off every object around him, and returned to his ears at the same rate, though vastly decreased in volume.
But not silent. Kish has trained himself to hear these slight echoes and to interpret their meaning. Standing on his front stoop, he could visualize, with an extraordinary degree of precision, the two pine trees on his front lawn, the curb at the edge of his street, and finally, a bit too far from that curb, my rental car. Kish has given a name to what he does — he calls it “FlashSonar” — but it’s more commonly known by its scientific term, echolocation.
Bats, of course, use echolocation. Beluga whales too. Dolphins. And Daniel Kish. He is so accomplished at echolocation that he’s able to pedal his mountain bike through streets heavy with traffic and on precipitous dirt trails. He climbs trees. He camps out, by himself, deep in the wilderness.
He’s lived for weeks at a time in a tiny cabin a two-mile hike from the nearest road. He travels around the globe. He’s a skilled cook, an avid swimmer, a fluid dance partner. Essentially, though in a way that is unfamiliar to nearly any other human being, Kish can see.
Kish and a handful of coworkers run a nonprofit organization called World Access for the Blind
There are two reasons echolocation works. The first is that our ears, conveniently, are located on both sides of our head. When there’s a noise off to one side, the sound reaches the closer ear about a millisecond — a thousandth of a second — before it reaches the farther ear. That’s enough of a gap for the auditory cortex of our brain to process the information. It’s rare that we turn the wrong way when someone calls our name. In fact, we’re able to process, with phenomenal accuracy, sounds just a few degrees off-center. Having two ears, like having two eyes, also gives us the auditory equivalent of depth perception. We hear in stereo 3-D. This allows us, using only our ears, to build a detailed map of our surroundings.
The second reason echolocation works is that humans, on average, have excellent hearing. We hear better than we see. Much better. On the light spectrum, human eyes can perceive only a small sliver of all the varieties of light — no ultraviolet, no infrared. Converting this to sound terminology, we can see less than one octave of frequency. We hear a range of 10 octaves.
Kish does not go around clicking like a madman. He uses his click sparingly and, depending on his location, varies the volume. When he’s outside, he’ll throw a loud click. In good conditions, he can hear a building 1,000 feet away, a tree from 30 feet, a person from six feet. Up close, he can echolocate a one-inch diameter pole. He can tell the difference between a pickup truck, a passenger car, and an SUV. He can locate trail signs in the forest, then run his finger across the engraved letters and determine which path to take. Every house, he explains, has its own acoustic signature.
He can hear the variation between a wall and a bush and a chain-link fence.
Bounce a tennis ball off a wall, Kish says, then off a bush. Different response. So too with sound. Given a bit of time, he can echolocate something as small as a golf ball. Sometimes, in a parking garage, he can echolocate the exit faster than a sighted person can find it.
When it’s all put together, says Kish, he has very rich, very detailed pictures in his head.
“In color?” I ask.
“No,” he says. “I’ve never seen color, so there’s no color. It’s more like a sonar, like on the Titanic.”
He attended the University of California Riverside, then earned two master’s degrees — one in developmental psychology, one in special education. He wrote a thesis on the history and science of human echolocation, and as part of that devised one of the first echolocation training programs. The ability of some blind individuals to perceive objects well before they could touch them was noted as early as 1749 by French philosopher Denis Diderot. He theorized it had something to do with vibrations against the skin of the face. In the early 1800s, a blind man from England named James Holman journeyed around the world — he may have been the most prolific traveler in history up to that point, Magellan and Marco Polo included — relying on the echoes from the click of his cane. Not until the 1940s, in Karl Dallenbach’s lab at Cornell University, was it irrefutably proven that humans could echolocate.
The thesis was the first time Kish really studied what he’d been doing all his life; it was the beginning, as he put it, of “unlocking my own brain.”
He then became the first totally blind person in the United States (and likely the world) to be fully certified as an orientation and mobility specialist — that is, someone hired by the visually impaired to learn how to get around.
From Koraling Lynne: Sign me up, because this is something taht will help everyone access and understand how to navigate through their environment.
No comments:
Post a Comment