Human echolocation can help blind 'see'

The ability to detect objects in the environment by sensing echoes from them is more than just a functional tool to help visually-impaired people, shows a study.

The study also tells that this ability has the potential to be a complete sensory replacement for vision.

Human echolocation operates as a viable "sense", working in tandem with other senses to deliver information to people with visual impairment, the findings showed.

"Some blind people use echolocation to assess their environment and find their way around," said psychological scientist Gavin Buckingham of Heriot-Watt University in Scotland.

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, Buckingham said.

Ironically, the proof for the vision-like qualities of echolocation came from blind echolocators wrongly judging how heavy objects of different sizes felt.

The experiment demonstrated 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.

The researchers had three groups taking part in the experiment: blind echolocators, blind non-echolocators, and control subjects with no visual impairment.

All three groups were asked to judge the weight of three cubes which were identical in weight but differed in size.

The study appeared in the journal Psychological Science.