Echolocation: the sound of the future?

By Lucy Williams

Durham research published last week demonstrates how human ‘echolocators’ can detect objects in a similar manner to bats, providing insights that could help teach more blind individuals the skills needed to improve their spatial awareness.

Echolocation is the ability to detect objects in the surrounding environment by sending out a biological sonar and interpreting the echoes. Famously present in bats, a similar skill has been independently developed by several blind individuals.

Human experts are able to identify objects by sending out a series of sharp mouth clicks, loud enough to penetrate background noise, and listening for the resulting echoes. With enough experience, the nature of the echoes allows them to gain insight into their surroundings.

Public awareness of the technique spread when Daniel Kish, an American expert in human echolocation who has been blind since the age of one, demonstrated and discussed his ability in a TEDx talk in 2015.

Although previous studies have established the accuracy of human echolocation and how it could be taught to blind children, the scientific basis around exactly how it is performed remained largely unknown. Published in the Proceedings of the Royal Society B last week by a team of psychologists from Durham University, the new study is the first to show that human echolocators instinctively adjust the intensity and number of clicks they make depending on the location of the target object.

The team, led by Dr Lore Thaler, asked eight blind expert echolocators to detect a 17.5cm disk reflector placed a metre from them at varying angles. When the disk was placed directly in front of the participants, all eight of them detected it after just one or two quiet clicks, whereas ten to twelve much louder clicks were needed to identify the object when it was placed slightly behind them.

Just like bats, human echolocators adjust their method based on the situation.

Echolocation could provide a complementary method to the use of guide dogs or canes to aid mobility, by improving spatial awareness and helping to avoid collisions at head or chest height. This new insight into how echolocation is performed could provide the knowledge needed to allow the skill to be taught on large scale, equipping blind individuals with tools to help explore new places and increase their independence.

The future is sounding good.

Photograph: WAFTB2016, via Wikimedia Commons

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