People with echolocation ability (thanks to GeekPress for the pointer). Wow.

Evan H (mail) (www):
Actually he's more like Daredevil.
8.16.2006 3:39pm
I watched this on TV the other night. I don't recall the names, but the first guy must have been Ben Underwood. He lost his eyes to cancer at a very early age. They showed him roller blading for pete's sake! It was remarkable.

As a side note, apparently his ability to echo locate is limited by how fast he make clicking noises. I think they said he can click something like a couple of times a second, thus couldn't identify objects smaller than say, a basketball. Bats can click (or whatever they do) much faster, and thus can identify and navigate around much smaller objects.
8.16.2006 3:40pm

As a side note, apparently his ability to echo locate is limited by how fast he make clicking noises.

You could get around that with an artificial clicker of some sort.
8.16.2006 3:52pm
cirby (mail):
You'd be surprised at how well regular folks can do this, too.

I can't ride a bike by sound, but I can get around in my house pretty easily with the lights off, from hearing the "closeness" of the walls (I got a good test of this two years back, when Hurricane Charley took out all of the lights for a few days).

Some time, cover your eyes and notice how the shape of the room "feels' in your ears.
8.16.2006 4:03pm
Silicon Valley Jim:
I believe that I've read that good outfielders use their ears (evidently unconsciously) to position themselves for fly balls, although it was long enough ago that I have no hope of finding the source for that.
8.16.2006 4:06pm
Dick King:
The frequency of the sound in each click [and the frequency response of the hearing], not how often the echolocater can click, determines resolution. Click frequency helps improve time resolution of the "scene". Too-frequent clicks can create ambiguity -- for example, if sound travels at 1000 feet per second and he makes clicks every ten milliseconds then things 3 and 8 feet away return similar signals, only the latter returns an echo from the second previous click, not the previous one. WWII-era ship radar had a button to push to change the pulse rate so this ambiguity would be resolved.

Of course if the click frequency is slow enough that any echo from the first click would be too weak to matter by the time the second click came out the ambiguity problem goes away.

8.16.2006 4:37pm
Dustin (mail):
absolutely amazing
8.16.2006 6:20pm
Ship Erect (mail) (www):
I was eager to see the first post--would it mention Daredevil? I was right!

Don't fall in love with a Greek assassin, Ben Underwood. Your greatest enemy, someone who has a deadly aim with every shot, will kill her!
8.16.2006 7:22pm
Dr. Lawrence Rosenblum, at the University of California, Riverside has trained undergraduates to echolocate. They all start out sure they cannot, but it takes the average blindfolded undergraduate about 10 minutes to consistently tell how far away a sliding wall is.
8.16.2006 8:01pm
It's no big deal. WhenI wander through my house at night with the lights off, I can always tell where the furniture is by listening to the sounds of my own yelps of pain.
8.16.2006 9:22pm
Silicon Valley Jim:

I don;'t have a reference either, but I've seen the same thing. It's a different property though. We sense orientation through an organ in our middle ear. By tracking the ball with your head, you can essentially solve the equation of the ball's motion to predict where it will land.

As I recall, it's basically as simple as keeping the angle of your head relative to the ground constant. If you do that through, you will be at (roughly) the place the ball will land. But don't quote me on that.
8.16.2006 10:18pm
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8.17.2006 12:05am
douglas (mail):
I can imagine learning to echolocate. I just can't imagine dealing with "Mom, I can't see anymore. I can't see anymore" with the strength and grace of his mother. Wow. God bless her.
8.17.2006 6:33am
Silicon Valley Jim:
SG -

Thank you for reassuring me as to the quality of my memory, and also for shedding some light on what's going on with the outfielders.
8.17.2006 2:29pm