By Bec Crew
People are learning to “see” in the dark – the same way dolphins and bats do.
Scientists have been teaching them how to get around using their ears rather than their eyes.
It’s called echolocation, which is what bats and dolphins use to make their way through black skies and murky waters.
Blind people do amazing things with echolocation – including riding a bike using nothing but clicks to “see” their way – but no one expected sighted people to get the hang of it so quickly.
It turns out it’s easy for anyone to put on a blindfold and learn how to create a mental picture of what’s around them, using echoes.
You make clicking noises with your tongue, and judge how the sound bounces off nearby walls and objects.
A team led by Virginia Flanagin, from the Ludwig Maximilian University of Munich in Germany, got 11 sighted people and one blind person together for an echolocation experiment which was published in the Journal of Neuroscience.
After they were shown what echolocation sounds like in a big room versus a small room, they were given control of a 3D simulation of a nearby church. Every room inside was pitch black.
The volunteers were asked to click their tongues inside different virtual rooms, and listen to the echoes.
Using the echoes, they had to guess the size of each virtual room.
After being trained for a couple of hours a day for two weeks, most of the sighted volunteers could figure out if a room was just 10 per cent larger than another one.
Dr Flanagin and her team were surprised at how close they got each time.
“Blind people are using sound to explore their environment all the time, so we didn’t expect sighted people to be as good, simply because after our training they went back to using vision to get around,” says Dr Flanagin.
But being able to see didn’t stop the volunteers from learning how to use sound to “see” things.
“Our best participant could already tell a 4 per cent difference in room size, which is like expanding the room by only 30 centimetres in every direction,” she says.
“Would you notice such a small difference by looking at it?”
Brains get rewired
Echolocation experts are already doing amazing things, she says.
Daniel Kish, in America, has been blind since he was one, but he uses tongue clicks to ride his bike and lead hiking trips through the mountains.
Dr Flanagin says studies like this help us figure out what happens in the brain when we take away one of our senses.
When people lose their sight, that part of the brain doesn’t dry up or stop working. Instead it’s rewired to do other things.
“This is true for people who lose their sight at an early age – usually until the age of eight to 10 – they tend to be the real echolocation experts,” she says.