Echolocation: Both Bats and Blind Humans Can Use it to See (Video)
Bats aren't the only ones that can use echolocation. Scientists have discovered that blind and visually impaired people may also have the potential to use the same ability.
In order to examine how hearing and, in particular, echolocation could be used to help improve the quality of life for the visually impaired, researchers conducted a series of experiments with both sighted and blind human listeners. They used a "virtual auditory space" technique in order to investigate the effects of the distance and orientation of a reflective object on ability to identify the right-versus-left position of the object.
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In order to conduct this experiment, the researchers used sounds with different bandwidths and durations, from 10 to 400 milliseconds. In addition, they used various audio manipulations in order to see which aspects of the sounds were important. The virtual auditory space allowed researchers to remove positional clues unrelated to echoes, such as footsteps and the placement of an object, and to manipulate the sounds in ways that wouldn't be possible otherwise.
After testing the volunteers, the researchers made some surprising discoveries. They found that both sighted and blind people with good hearing showed the potential to use echoes to tell where objects are. That said, the ability to hear high-frequency sounds is required for good performance, so those with common forms of hearing impairment probably won't be able to use the technique.
"Some people are better at this than others, and being blind doesn't automatically confer good echolocation ability, though we don't yet know why," said Daniel Rowans, one of the researchers, in a news release. "Nevertheless, ability probably gets even better with extensive experience and feedback."
The ability to use echolocation has been seen before in blind patients. In fact, Ben Underwood demonstrated an ability to navigate the world with the use of clicks in 2006. After having his eyes surgically removed when he was a child due to cancer, Underwood learned how to skateboard, walk along a street and conduct other tasks by merely listening. He eventually died at the age of 16 in 2009 after a resurgence of his cancer.
This new study, though, highlights the potential to teach people to use the same technique that Underwood used. It could allow researchers to develop training programs and assistive devices for the blind. Currently, researchers are extending their studies to investigate finding objects in a three-dimensional space.
The findings are published in the journal Hearing Research.
Want to learn more about Ben Underwood? Check out the video below, courtesy of YouTube.