Like Bats, Humans Can Echolocate to Replace Their Vision

People may just have the ability to use echolocation. Scientists have found that human echolocation operates as a viable "sense," working in tandem with other sense to deliver information to people with visual impairment.

In order to find out if human echolocation was viable, scientists tested echolocators. More specifically, they showed that echolocators experience a "size-weight illusion" when they use their echolocation to get a sense of how big objects are, in just the same way as sighted people do when using their normal vision.

"Some blind people use echolocation to assess their environment and find their way around," said Gavin Buckingham, one of the researchers, in a news release. "They will either snap their fingers or click their tongue to bounce sound waves off objects, a skill often associated with bats, which use echolocation when flying. However, we don't yet understand how much echolocation in humans has in common with how a sighted individual would use their vision."

The scientists actually tested three groups: blind echolocators, blind non-echolocators and control subjects with no visual impairment. These groups were asked to judge how much three different cubes weighed; each cube was identical in weight but differed in size.

"The blind group who did not echolocate experienced no illusion, correctly judging the boxes as weighing the same amount as one another because they had no indication of how big each box was," said Buckingham. "The sighed group, where each member was able to see how big each box was, overwhelmingly succumbed to the 'size-weight illusion' and experienced the smaller box as feeling a lot heavier than the largest one."

The findings reveal that echolocators seem to have the same illusion as the non-visually impaired. This means that echolocators use the "visual" regions of their brain when listening to their own echoes. More specifically, it shows that echolocation is a functional tool and has the potential to be a complete sensory replacement for vision.

The findings are published in the journal Psychological Science.

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