Will Blind People One Day Be Able to Echolocate Like Bats?

New research into human hearing suggests than humans have at least some ability to use echoes to locate their position in space, similar to the well-developed and well-known ability of bats. Though we're just in the preliminary stages of understanding it, it's a fascinating thing to consider.

What we now know: Research coming out of the University of Southampton Institute of Sound and Vibration research, published in the journal Hearing Research, shows that as long as there is no hearing impairment—that is the ability to be able to hear sounds above 2 kHz (in the range of normal human conversation)—both sighted and blind people have the potential to use echoes to determine where nearby objects are located even if they can't see them, and even when other audio clues are eliminated.

"We also found that our ability to use echoes to locate an object gets rapidly worse with increasing distance from the object, especially when the object is not directly facing us," lead author  said. "Furthermore, some echo-producing sounds are better for determining where an object is that others, and the best sounds for locating an object probably aren't the same as for detecting the object or determining what, and how far away, the object is."

As for future development of these abilities, the researchers say that this study offers insights into how training programs for the blind, as well as sighted people in low-vision situations, might be developed. Though it's pretty standard to say so at the end of any scientific paper, even more so here, more research is needed.

"Some people are better at this than others, and being blind doesn't automatically confer good echolocation ability," said Rowan. "Nevertheless, ability probably gets better with ability."

Echolocation is fairly common in the animal kingdom. It's known to be used by insect-eating bats, one species of fruit bat, toothed whales and dolphins, a few species of birds, and, in a simple form, by some shrews. It works by sensing the difference in timing between when a sound arrives in one ear and then the other, as well as the relative intensity of the sound.

In the case of bats, sounds are generated specifically for this purpose. These sounds in the 14000-100,000 Hz range, mostly outside the range of human hearing. When searching for food clicks are made 10-20 times per second. Once prey is detected this can climb as high as 200 times per second, gradually decreasing as the insect is approached.

All of which is to say that whatever potential ability humans have (and it does seem that there is some potential), we're not bats just yet. Training people to use it in a practical way, particularly in real-world settings and not the highly-specialized and controlled laboratory settings used here, is a long way off.