"Now wait here," he says. Though he was born and raised in Southern California, Kish has an odd, almost foreign-sounding accent – a bouillabaisse of Canadian, British, and relaxed Los Angeleno. He says it's a result of his many travels. "I'm a natural mimic," he explains. Kish is 5-foot-7, thin and fit, with an impressive mane of dark brown hair and a meandering winestain birthmark on his left cheek.
I hear him walk into his kitchen, his bare feet padding faintly on the hardwood floor. "I'm very particular about feeling life and air around my feet," he once wrote in the journal he braille-typed and shared with me. I'm barefoot as well. Kish asked me to remove my shoes, which is one of his many little rules you quickly learn to adopt. Like: He's Daniel Kish, and anyone who calls him "Dan" more than once may be struck with withering disdain. And don't disturb him during his sleep time – lately, he's been sleeping just two hours twice a day, usually from 5 to 7 in the morning and again from 5 to 7 in the evening. He often stays up all night dealing with World Access logistics. He lives alone and does not have a significant other. He plays a lot of Celtic hymnal music.
I listen as Kish opens a cabinet and rummages amid his pots. He returns and stands behind me. "Make a click," he says.
It's a terrible click, a sloppy click; what Kish calls a "clucky click." Kish's click is a thing of beauty – he snaps the tip of his tongue briefly and firmly against the roof of his mouth, creating a momentary vacuum that pops upon release, a sound very much like pushing the igniter on a gas stove. A team of Spanish scientists recently studied Kish's click and deemed it acoustically ideal for capturing echoes. A machine, they wrote, could do no better.
My click will work for now. Kish tells me that he's holding a large glass lid, the top to a Crock-Pot, a few inches in front of me. "Click again," he says. There's a distinct echo, a smearing of sound as if I'm standing in my shower. "Now click," he says. The echo's gone. "I've lifted it up. Can you tell?"
I can, quite clearly. "Click again," he instructs. "Where is it?" I click; there's no echo.
"It's still lifted," I say.
"Try again," says Kish. "But move your head, listen to your environment."
I turn my head to the right and click. Nothing. Then I click to the left. Bingo. "It's over here," I say, tilting my head in the direction of the lid.
"Exactly," says Kish. "Now let's try it with a pillow."
There are two reasons echolocation works. The first is that our ears, conveniently, are located on both sides of our head. When there's a noise off to one side, the sound reaches the closer ear about a millisecond – a thousandth of a second – before it reaches the farther ear. That's enough of a gap for the auditory cortex of our brain to process the information. It's rare that we turn the wrong way when someone calls our name. In fact, we're able to process, with phenomenal accuracy, sounds just a few degrees off-center. Having two ears, like having two eyes, also gives us the auditory equivalent of depth perception. We hear in stereo 3-D. This allows us, using only our ears, to build a detailed map of our surroundings.
The second reason echolocation works is that humans, on average, have excellent hearing. We hear better than we see. Much better. On the light spectrum, human eyes can perceive only a small sliver of all the varieties of light – no ultraviolet, no infrared. Converting this to sound terminology, we can see less than one octave of frequency. We hear a range of 10 octaves.
We can also hear behind us; we can hear around corners. Sight can't do this. Human hearing is so good that if you have decent hearing, you will never once in your life experience true silence. Even if you sit completely still in a soundproof room, you will detect the beating of your own heart.