Y: Don, have you ever heard of echolocation?
D: Sure I have Yaël. Echolocation is the ability of bats and dolphins to learn about their surroundings by emitting sounds, and analyzing the returning echoes. It's like a kind of natural sonar. Bats use it to hunt and capture flying insects in total darkness. Dolphins use it to sense their surroundings in the murky depths of the sea.
Y: But, did you know that some people have the ability to echolocate, too?
D: You've got to be kidding!
Y: It's true. Scientists have shown that many blind people develop enhanced hearing abilities. Some have learned to use the returning echoes of tongue clicks or finger snaps to give them a crude knowledge of the directions, distances, shapes, and sizes of objects in their surroundings.
In their daily lives they can use this ability in activities such as exploring cities and hiking. Some of them can even play basketball or avoid obstacles while riding a bike.
D: People usually use sight to do those things.
Y: Yes, that's true, and neuroscientists have shown that this is a case of sensory substitution. When blind people echolocate, some of the same brain areas that sighted people use when they assess objects visually become active. They even experience some of the same perceptual illusions as for vision.
D: I can't even imagine what that would be like.
Y: It really isn't as strange as you think. In all of us, the senses work together to help us learn about the world. Researchers have shown that sighted people can be taught to echolocate too. In bats and dolphins, these abilities have simply become much more highly developed.