By ‘echolocating’: study

Just as bats bounce sound waves off objects to find their way in the dark, some blind humans spontaneously make clicking sounds with their mouths to navigate the world, scientists said on Wednesday.

Not only that, but they adjust the speed and volume of the clicks when they need to zoom in on a hard-to-place object. "Even though people have not been 'designed' to echolocate, they have adapted their brains extraordinarily well to detect faint echoes and to instinctively adjust emissions as the task changes," said Lore Thaler of Durham University in the UK, co-author of a study published in the journal Proceedings of the Royal Society B.

The research team tracked down eight blind people with experience in echolocation for the study.

They placed the "expert echolocators" in a noise-insulated room, then conducted experiments by placing a wooden disk at different angles from the person always at a distance of a metre.

Standing in one place and without moving their heads, the subjects' task was to make clicking sounds with their mouths to determine whether the disk was present in the room or not.

At zero, 45 and 90 degree angles, the participants were correct 100 % of the time, the researchers found.

Their success rate dropped to about 80 % when the disc was placed at an 135-degree angle. At 180 degrees, directly behind them, the participants were correct half the time. AFP

Source: http://www.thehindu.com/todays-paper/tp-in-school/how-visually-impaired-use-clicks-to-see/article22926954.ece?utm_source=tp-in-school&utm_medium=sticky_footer