Human Echolocation

Like bats, dolphins and most whales, some humans have the ability to use echolocation. In the late 1940s the scientific community took notice of some blind individuals who were able to navigate around obstacles without touching them. The original theory was that the closeness of an object caused pressure on the skin which these people were using. However after some tests it became apparent that it was actually sound which was the medium for the ability.

Up until the 1950s there were no documented cases of a person actively using this ability, it was simply a passive sense which some blind people picked up innately. However, since then a more active form of echolocation was been developed and tested. The person produces a series of clicks either with their tongue or by tapping their cane which bounce off nearby objects and bounce back to the ears of the user. While the effect is less effective than the scenes in the early 2000s Daredevil, the idea is the same. Experienced practitioners can pick out the size, shape and density of objects. Convex curves such as spheres and cylinders prove the hardest to hear because they disperse the sound waves, but even they can be located.

The best users in the world are seriously good. Some can ride bikes through heavy traffic, hear not only where a table is but also whether it is made of metal or wood or navigate along roads on a skateboard. The great pioneer in these skills is Daniel Kish, who lost his eyes to retinal cancer at the age of 1; in fact most of the famous practitioners have been his students.

In studies of the subject it was found that the parts of the brain which were activated when using the ability were the parts normally associated with visual interpretation. In one experiment the researchers got echolocators to identify a series of objects, but recorded the audio at the same time. When the same audio back the users were still able to correctly match the recording with the object.

The ability is not exclusive to blind people and various sighted people have taught themselves the ability. However the effect is usually much more limited and scans of their brain while they use the ability show little to no activation of the visual cortex. Still, it shows that echolocation is an innate human ability.