By Rose Horgan
Despite echolocation being discovered first in bats in 1940, there are reports of blind people using sounds to navigate as far back as the 1700s. Echolocation is the ability to use reflected sound to collect information about the environment. Humans can use echolocation passively by listening to echoes of ambient noise, or actively by making taps or clicks, then listening to how the sound reflects off surroundings.
Whilst humans are not designed for echolocation like animals such as dolphins who can make 200 clicks per second, this skill allows people with vision loss to live independently.
A team of researchers led by Dr Lore Thaler, of Durham University, investigated whether age and blindness affect a person’s ability to learn echolocation. Sighted and blind participants aged between 21 and 79 were trained over ten weeks. The training focused on using tongue clicks to navigate indoors and outdoors, as well as to determine the size and orientation of objects.
Surprisingly, when the degree to which participants improved over the training programme was quantified, there was no evidence to suggest that age is a limiting factor. This gives positive news that any age is a great age to learn echolocation.
This is also in contrary to research showing that neuroplasticity decreases with age. Neuroplasticity is the capability of the brain to form new connections, and therefore learn new skills, so it was expected that older participants would improve less. It is likely that this trend was not seen because the sample was made up of thirty-three people, only three of whom were over the age of 60. Although it is possible that our grandparents are more capable than meets the eye!
Tongue clicks have an advantage over lower frequency sounds such as foot taps because higher frequency sounds reflect better, giving more information about surroundings. In addition, they produce a clearer sound. Indeed click-based echolocation was even successful in the experiment in environments like a classroom with moderate background noise.
Daniel Kish, a blind man who trains others in click-based echolocation, proves its effectiveness by navigating around parked cars and trees on his bike. Whilst Kish was initially uncomfortable being called Batman, he remarked that “[Batman’s] super-abilities do not come from magic, or the fourth dimension, or another planet. . . . He’s a human that has refined himself to be the best he can.”
Cycling with click-based echolocation highlights a major advantage to this skill: it can be used at a greater speed than walking with a cane alone or other forms of echolocation.
This is perhaps why Dr Thaler’s research has such positive results from a survey conducted three months after training with the blind participants. All reported better mobility, with 83% feeling that their independence and welfare also improved. Fantastically, by the end of training, both sighted and blind participants matched the ability of echolocation experts to determine orientation of objects and to navigate an unfamiliar maze. This is extremely exciting for vision loss rehabilitation programmes in the UK, since click-based echolocation is currently not a part of mobility training and rehabilitation for vision loss at all.
You can experience echolocation without training by making shushing sounds towards a wall and listening for a change in sound as you move closer or further away. In fact, echolocation may be a worthwhile skill for sighted people too as it can help you to navigate dark or smoky environments.
Currently firefighters use thermal imaging cameras to see in smoke, but perhaps echolocation training would equip them to make faster rescues. Experienced echolocators can easily distinguish doors and people in a room, whereas only high sensitivity thermal imaging cameras will make objects easily seen.
Illustration: Verity Laycock