Perhaps one should not really say that Daniel Kish “discovered” human echolocation. Yet, having no other options as a blind infant cancer survivor, he discovered early on — and began to publicize — a sense that few sighted persons would even think of:

He calls his method FlashSonar or SonarVision. He elaborated for the BBC:

Do people need to be blind to do it? Not necessarily:

In 2021, a small study led by researchers at Durham University showed that blind and sighted people alike could learn to effectively use flash sonar in just 10 weeks, amounting to something like 40 to 60 hours of total training. By the end of it, some of them were even better at specific tests of their spatial perception than long-time experts of the technique.

When the average person off the street hears clicks like the ones Kish uses, their brains just hear noise. They react the way they react to the sound of a man clicking his tongue. But something different happens in your brain if you’ve learned to use flash sonar like Kish has. And it’s different between sighted people and blind people. If you can see, parts of your brain associated with auditory processing light up: you’re recognizing that there is information encoded into these clicks, and you’re looking for it with the part of your brain that interprets audio.

Rachel Feltman, “FACT: Echolocation might be a much more common human ‘superpower’ than you think” at PopSci/Popular Science (August 10, 2022) The paper is open access.

But, of course, if a person is blind, such a skill becomes proportionately much more important:

In 2000, Kish founded World Access for the Blind as a platform to teach FlashSonar, along with other methods that the blind can use to “see” and that the sighted can use to expand their awareness. Kish and many researchers believe that echolocation produces images similar to sight, and allows the visually impaired to transcend the limited expectations of society.

– “Daniel Kish, Perceptual navigation specialist” at TED Talk and transcript.

Here’s a neuroscience look at what’s happening:

We often hear that human senses are inferior in various ways to those of other life forms. But the reality may be more like this: Our binocular color vision is very convenient so we rely on it heavily and we build communications systems around it. So vision crowds out other senses. But it turns out, humans can echolocate if we must. And — as other research shows — our sense of smell is also much better than we think.

Somewhat inelegantly, Kish, who has appeared in films, is sometimes called the “real-life Batman.” Actually, The DC Comics Batman barely uses echolocation and then mainly via gadgets. This sense had to be formally rediscovered by a man with a real-life need.

You may also wish to read: The nose really does know, it turns out… But we usually don’t notice. Our sense of smell may have declined in recent millennia but it is sharper than we think. Losing one’s sense of smell — as with COVID — is dangerous as well as traumatic but, relative to other senses, we don’t yet know much about how it works.

and

Neuroscientists: We hear when we are asleep — we just don’t listen. The new finding may help determine whether an apparently unconscious or demented person can actually understand what is said to him. Contrary to earlier assumptions, the team found that, during sleep, brain communications areas receive sound signals — but don’t react to them.