WHAT is it like to be a bat? It’s a question philosophers interested in consciousness like to ponder. Yet a few people already have something of a bat’s world view.
Brian Borowski, a 59-year-old Canadian who was born blind, began teaching himself to echolocate aged 3. He clicks with his tongue or snaps his fingers as he moves about, unconsciously decoding the echoes. Although many blind people get information from sounds around them, few turn this into a supersense by making sounds to help themselves get around.
“When I’m walking down a sidewalk and I pass trees, I can hear the tree: the vertical trunk of the tree and maybe the branches above me,” says Borowski. “I can hear a person in front of me and go around them.”
Borowski, who works as a programmer at Western University in London, Ontario, suspects he experiences “images” in a similar way to people who can see, just with less detail. “I store maps of information in my head and I compare what I have in my memory with what I’m hearing around me,” he says. “I am matching images of some sort.” This probably isn’t too far from the truth – we know from brain scans of Borowski and another echolocator that the strategy co-opts the same parts of the brain that usually deal with visual information.
I store maps of information in my head. I compare what is in my memory with what I’m hearing around me
For his latest scientific collaboration, he helped a team of researchers to explore how well echolocators can determine the relative sizes and distances of objects. Sighted people normally have no problem knowing whether objects appear small because they are far away or because they are actually small – yet both something small and nearby or large and distant would occupy the same area and angle in our field of view. “It’s not a trivial thing,” says team member Lore Thaler, at Durham University, UK. “But we don’t think about it.” So is it also easy for echolocators? You might think so, but previous work has suggested that echolocating bats sometimes struggle.
Borowski, however, aced the tests, consistently identifying the true size of a range of objects placed at different distances. In contrast, 20 blind or blindfolded people who had no experience with echolocation floundered when asked to give it a try (Neurocase, doi.org/38g).
As for how he does it, Thaler points out that theoretically, echoes contain intrinsic information about the source’s distance as well as its size, taking longer to return from far-away objects. But Borowski feels he’s using a different strategy. “If you’re close to something, you hear a higher resolution. You get more detail,” he says.
Human echolocation has attracted great interest since the late 2000s, when Californian Daniel Kish came to wide attention. Yet his organisation, World Access for the Blind, is still the only one that teaches the skill to others, and it is not generally taught to blind children in schools. Tom Pey of the Royal London Society for Blind People points out that most people who are blind or partially sighted lose their sight in later life, when their hearing might also be on the wane.
Thaler admits that echolocation has some drawbacks – it’s not very good for detecting obstacles on the ground – but she is convinced it should be taught, and is currently helping Durham County Council to provide workshops. “It doesn’t solve everything but it definitely gives additional information,” she says. “It’s an amazing example of brain plasticity.”
How I learned to echolocate
Read more: Click here to read a longer version of this interview
Once, when my parents were putting metal stakes into the ground, my brother – who is also blind – and I noticed that when they were banged with a hammer, the echoes bouncing off the house were really strong. We realised we could use that.
Playing games like hide-and-seek with our sighted brother honed our skills. His idea of hiding from us was standing in the middle of the lawn. At first we couldn’t find where he was, but as we got better at echolocating, he had to hide behind trees. We soon learned to find him there too.
Once we’d mastered the skill, we taught ourselves how to ride bikes. We didn’t just use echolocation, but other things too to keep track of where we were: the slope of the road, whether the gravel was loose or well-packed. But we would always be clicking, listening for the grass growing at the side of the road, or for the turning into our driveway.
We never had any formal training. Our teachers thought it wasn’t a good thing to do. They said blind people have enough trouble fitting into society and you shouldn’t do anything that causes you to be more different than you already are. But we more or less ignored them.
When I was younger I could get a lot of detail from echolocation. These days I can tell whether objects are large or small but I can’t necessarily tell what they are. Brian Borowski, as told to Clare Wilson
This article appeared in print under the headline “The man who sees with sound”
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