For years, a small number of people who are blind have used echolocation, by making a clicking sound with their mouths and listening for the reflection of the sound to judge their surroundings. Now, research published in PLOS ONE shows that people can learn click-based echolocation regardless of their age or ability to see, Alice Lipscombe-Southwell reports for BBC Science Focus magazine.
Researchers led by psychologist Lore Thaler at Durham University spent ten weeks teaching over two dozen people, some who were blind and some who were not, to observe and navigate their environments by echolocation. Participants attended two sessions per week for two to three hours each time.
After the training, the researchers compared the participants’ ability to use echolocation to seven people who had been using the technique for over a decade. The researchers also followed up with blind participants three months later to see how the echolocation affected them long-term.
"I cannot think of any other work with blind participants that has had such enthusiastic feedback,” says Thaler in a statement. "People who took part in our study reported that the training in click-based echolocation had a positive effect on their mobility, independence and well-being, attesting that the improvements we observed in the lab transcended into positive life benefits outside the lab."
Participants were between 21 and 79 years old, and included 12 people who are blind and 14 people who are not blind. Over their ten weeks of echolocation training, they faced tasks like using clicking to figure out whether the pair of disks in front of them had a larger disk at the top or bottom or to identify how a rectangle plank was oriented. Participants also navigated obstacles virtually in the lab, and outside of the lab, they navigated using clicking and a long cane.
The results showed that all of the participants could learn how to echolocate, regardless of their age or whether they were blind. Some of the study participants even did better at their tasks when compared to the seven expert echolocators, who have more than a decade of experience using echolocation to navigate.
“What made us explore it in the first place was that it is just such a fascinating skill, and that it has such great potential to help people who are blind and to investigate neuroplasticity on a more general level,” writes Thaler to Gizmodo’s Ed Cara in an email. “We also plan to investigate how teaching and learning of this skill would scale up from the lab to professional instruction (i.e. how do people learn and benefit when they are not trained by researchers but by visual impairment professionals).”
The researchers also hope to find out whether echolocation could be taught to people who realize that they are losing their eyesight because of a degenerative illness, per the statement.
Thaler’s previous research on echolocation identified the “cone of perception” created by each click, Nathan Hurst reported for Smithsonian in 2017. Clicks create a 60-degree cone where perception is most detailed, and past research has shown that information gathered from echolocation is processed in the same part of the brain that processes visual information.
“You could fill libraries with what we know about the human visual system,” said Daniel Kish, who participated in the 2017 study and uses click-based echolocation, to Smithsonian in 2017. “But what we know about human echolocation could barely fill a bookshelf.”