With both eyes lost to cancer when he was just a toddler, you'd expect Daniel Kish to be as blind as a person can get. He's become famous for using a sort of human echolocation to find his way around, but there's more to it than that: According to Kish, his fellow echo-locators, and the scans of their brains, they're actually seeing. 

Let's step back for a second. What does it mean to see? If you have normal eyesight, you probably think of sight as the ability to take a perfect picture of the world in front of you using your eyes. But that's not how vision works. The sights we "see" are produced inside our own brains. Our eyes are certainly well-designed input devices, giving us sharp, colorful outputs of the world. But what if another part of your body collected the data used to create those inner pictures instead?

On this week's "Invisibilia," NPR's new science podcast, hosts Alix Spiegel and Lulu Miller interview Kish as the ultimate example of triumph over the expectations of others.

You've probably seen videos of Kish: He clicks his tongue against the roof of his mouth and uses the feedback he hears to produce a kind of sonic representation of his world. No one taught him to act like a bat -- he's just been doing it since he was a rambunctious, adventurous, totally sightless toddler.

People tend to freak out over Kish's ability to ride a bike without veering off into traffic. It's certainly amazing to watch, but Kish says that the world's amazement with him is what keeps blind people blind.

"I definitely think that most blind people could move around with fluidity and confidence if that were the expectation," Kish told "Invisibilia." "If our culture recognized the capacity of blind people to see, then more blind people would learn to see. It's actually - it's pretty simple and straightforward.

Learning to get around the way Kish does (something he teaches through his organization World Access for the Blind) is tough for adults, but doable. But it's much easier for kids. And once they get there, they experience something that's hard not to call sight.

"I definitely would say that I experience images, that I have images," Kish told NPR. "They are images of spatial character and depth that have a lot of the same qualities that a person who sees would see."

Kish's friend Brian Bushway, who had normal vision until he was a teenager and now uses echolocation, backs this up. By learning the new way of seeing, he said, he went from total blindness to something a lot like his former vision.

"Things are real," Bushway told NPR. "I mean, it's as real as looking at it."

Durham University neuroscientist Lore Thaler tested this notion by watching the brain activity of people like Kish and Brian. She wanted to see what their brains were doing when they listened to the clicks they produced. Their visual cortexes weren't just active -- they reacted much more like a brain "seeing" different objects and objects in motion than like a "blind" brain would.

According to other studies, Miller and Spiegel report, this vision may be something like healthy peripheral vision. You might not be able to recognize the driver in a car that passes while you're looking down at your phone, but that doesn't mean you can't "see" the car.

It's a bit of a mind melting notion, to be sure. But maybe you don't need eyes to see.

You can hear more about Kish on "Invisibilia."

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