Wednesday, 11 February 2015

Human Echolocation: You’re only as blind as you want to be

This article goes out to the amazing Amy Kux on her birthday. Happy birthday Amy!

If you take a stroll around the animal kingdom and look at all the amazing abilities that different creatures possess, it is easy to become jealous. Sure, us humans are the brainiest of the bunch and we have used our smarts to make up for some of the physical deficits nature has left us with, but riding in a car going 70 miles (112 km) per hour just doesn’t have the same coolness factor as being able to reach that speed on foot, like a cheetah can. Even the best human sprinters would be hard pressed to catch a squirrel. We can’t fly like birds or swim like dolphins. We aren’t as strong as gorillas and we can’t track criminals with our noses like a bloodhound. However, there is one superhuman ability that science is beginning to realize that some of us have an unexpected knack for...

Most people are familiar with the concept of echolocation. It is the ability of some animals (ex. bats, some birds, whales, and dolphins) to detect objects in their environment by emitting high frequency sounds and listening to how they bounce of different surfaces to create a sort of mental image of the world. Typically these sounds are too high pitched for human ears to pick up, further adding to the mystique of this impressive skill. The thing is, it might not be so beyond our ability to grasp.

We don’t spend a lot of time thinking about how we perceive sounds, so it is easy to think that we aren’t very good at it. Humans have evolved to rely on our eyes to a ridiculous extent. The idea of losing our vision is terrifying to some people, but that is likely because most of us have never tested our ability to navigate using other senses. Rest assured, you are more skillful than you think. If you don’t believe me, try to think back to the last time you were in a really big space like a church or an airport terminal. Think about the things you heard and how they were different from the sounds that reach your ears while sitting on a soft couch in a carpeted room. Odds are if I blindfolded you, put you in one of those places and asked you which it was you wouldn’t have much trouble telling me.

Beyond the ability to distinguish between when we are at home watching Netflix and when we are about to board a plane to Prague, our ears are also good at determining the direction that sounds are coming from. You probably don’t realize it, but when you hear a bird chirp or a car backfire your two ears receive the sound at slightly different times. Your brain is able to use this difference to determine where in space the noise came from and we can turn our heads toward it without even thinking. Just like how your two eyes let you see in three dimensions, your ears let you hear in three dimensions.

A few of us, it turns out, can take what our ears can do to a level that is beyond belief. Some people who have been blind for a long time can click their tongues and detect the way the sound waves bounce off objects around them, very similar to how bats and whales do it. Apparently this is actually something that most people can learn to do. One study found that, over time, blindfolded participants could learn to tell the difference between large and small objects placed in front of them using only tongue clicks. With more practice, research has shown that people can learn to walk down hallways while blindfolded without touching the walls simply by listening to how sounds are echoing around them.

Human echolocation is something that people like Daniel Kish, founder of World Access for the Blind, have known about for a long time. Kish, who lost his eyes to cancer as a toddler, taught himself to echolocate as a child so he could know how high up he was in the trees he was climbing. As an adult he is often annoyed at the surprise people express when he rides by them on his bicycle, clicking all the way. Experts like Kish, research has shown, can use clicks and head movements to determine the distance, size, density, movement and even the contours of objects.

Kish’s message to other blind people is not to believe the world when it tells you that you can’t do something. You are as capable as you believe you are. That’s something we should all try to remember, especially as we navigate a world full of animals that appear to have us outmatched.

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