Ever heard (no pun intended) of echolocation? It’s the ability of some animals, most famously dolphins and bats, to emit sound waves to determine the location and size of objects around them, which helps them “see.” Scientists have long known that some blind humans shared this skill and were able to also emit clicking sounds to “see” with their ears. But a recent study published in Psychological Science confirmed just how powerful human echolocation is — ironically, by showing how those who use it fall prey to the same “size-weight illusion” as people who can see.
Gavin Buckingham, a psychological scientist at Edinburgh’s Heriot-Watt University, conducted an experiment with the cooperation of six blind people, three of whom could use echolocation and three who could not, and four sighted people. They were presented with three boxes of different sizes but of similar weight. While blind non-echolocators correctly found that the three boxes weighed the same, sighted people and echolocators thought that the bigger boxes weighed more than the smaller ones, a phenomenon known as the Charpentier illusion.
Echolocators “also got it wrong,” a delighted Gavin Buckingham told Le Monde. “Though they were not as bad as the sighted people, because their perception is more precise and blind people can generally better appreciate the weight of objects. But the difference between those can echolocate and those who can’t is still an important one. Echolocation is indeed an alternative vision that is built and capable of influencing other senses,” he explained.
See how echolocation works with Daniel Kish, president of the non-profit organization World Access for the Blind whose nickname is “the real life batman.”