Human Echolocation

When a person is blind, simple navigation can be quite a challenge. Human beings generally navigate visually, using vision to determine the location and distance of objects. Besides the standard tools of navigation the blind use, such as a cane or a seeing-eye dog, some blind people have been able to master a technique called echolocation. This involves making a sound, like the snapping of fingers or the clicking of a tongue, and interpreting the echoes those sounds make off of nearby objects. It's the same principle as active sonar or the navigation techniques employed by certain animals such as dolphins or bats. Submarines use sonar to navigate and detect other objects (such as other submarines) while submerged, when visual navigation is impossible.

While the phenomenon known as human echolocation has been known since the 1950s, it was defined and developed by a man named Daniel Kish. Blind from birth himself, Kish is the Executive Director of the World Access for the Blind where he teaches human echolocation techniques as well as other mobility techniques for the blind.

Human echolocation, after much practice, can help a blind person determine the height, width, location, and even density of environmental features, Using human echolocation, a blind person can "see" his or her environment 360 degrees, though the portion toward the front is "seen" with much more clarity.

Kish cautions that human echolocation can go only so far. He recommends the use of a cane or walking stick to navigate over uneven terrain, as human echolocation is unable to detect drop offs.

Training techniques for human echolocation vary according to the abilities of the student. Generally closer, larger, and simpler objects are easier to perceive than those that are farther, smaller, and more complex. Training in human echolocation in a static situation is easier than training in the technique while on the move.

The most famous practitioner of human echolocation, besides Kish, is a teenaged boy named Ben Underwood. Underwood has been featured on CBS and ABC News, as well as the Ellen DeGeneres Show and People Magazine. Underwood has been blind since early childhood, having his eyes removed due to a cancer. Nevertheless, using human echolocation techniques, he can navigate and even play games such as foosball with the same confidence as a sighted person. The remarkable thing is that Underwood was not taught in the echolocation technique, but like Daniel Kish seems to have developed it on his own.

Technology under development may well vastly improve the ability of blind people to use human echolocation to navigate. Devices that can send out sound and then help blind people interpret the echo will greatly enhance human echolocation. A device called SoundFlash is under development by the World Access for the Blind and should be available in the near future.