Can you hear better?

The quest to build better people.
March 10 2003 2:46 PM

Hearing Aid

Is there a better ear?

(Continued from Page 1)

The Perfect Pinna

Hearing directions
Hearing directions

The Background The human ear is bad at only one task that matters: We have a hard time telling the difference between sounds that are behind us and sounds that are in front of us. A noise from the front may sound like it's from the rear and vice versa.

It turns out that our ability to locate these kinds of sounds is largely determined by the shape of the pinna.

According to Wisconsin's Wightman, the more ridges and folds in the pinna, especially in the upper part, the better we locate sound behind us. Sound waves from the rear bounce around the pinna; the brain uses those bounces to triangulate position. The more convoluted the ear, the more bounces; the more bounces, the better the brain processes the noise. (Wightman describes a visit to his lab by a famous acoustician. The acoustician pointed at a patient's simple pinna and predicted she would have lousy directional hearing. She did.)

The Project
There may be a perfect pinna, a French-braided ear, and with more investigation, researchers might be able to figure out exactly what it looks like. Wightman believes doctors might someday be able to surgically modify pinnas or construct pinna prosthetics that would vastly improve directional hearing. No one has yet tried to make perfect pinnas, but prosthetics have been used successfully on people with damaged pinnas, and it would probably not be very difficult to design an ideal one. Once it was attached, you would need a few weeks to adjust, but when you did, you would have ears in the back of your head, so to speak. Soon, Wightman says, only half-joking, "We could have centers for cosmetic pinnology."

Why Bother?
There is no great technical obstacle to such adjustment, but is it worth the effort? Very few of us regularly need to hear what is going on behind us. Unless you're a teacher who must know who is throwing spitballs, you're unlikely to crave a twistier pinna. Few people would subject themselves to the hassle of surgery for such a meager benefit.

The Timeline
Soon, if anyone wants it.

Hearing Faster

The Background
The military is fascinated by the prospect that soldiers could learn to process more information more quickly. Can GIs, in essence, learn to hear faster? Information about this is hard to come by—none of the military scientists I phoned returned my calls—but according to civilian researchers I interviewed, the Air Force is studying it.

The Project
According to one civilian scientist who has spoken to military colleagues, the Air Force has experimented on pilots and air traffic controllers to determine whether they could work faster if they heard differently. In one experiment, as it was explained to me, the Air Force feeds information about right-side events into the right ear and information about left-side events into the left ear. That is, an air traffic controller might receive updates about planes to the east in his right headphone and planes to the west in his left headphone. The broadcast might even be precise enough that southern planes would sound like they were behind him. So far, the civilian scientist claims, the military trials have been very successful: The "spatial attribute" lets participants process information more accurately and quickly. In essence, they hear faster.

Why Bother?
This enhancement has a few specialized uses. Spatial information is the only application I could think of, and even that's a narrow market. Just as most people don't need special pinnas, most of us don't need to hear vast amounts of space-sensitive information in a very short time. It would be reassuring if air traffic controllers could, though.

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