I find this fascinating...

You know that bats use echolocation to navigate at night, in extreme darkness, right? They emit a sound and use the echoes from the sound to locate and avoid objects, or to locate and catch and eat bugs or other prey.

But did you know that humans can develop this ability, too?

A recent article in Psychology Today magazine tells of some blind mountain bikers who use echolocation to navigate the trails. Amazing.

The article describes the basic process of echolocation:

To get a sense of how echolocation works, try this. Hold your hand up about one foot in front of your face with your palm facing your mouth. Put your front teeth together, open your lips, and make a continuous shhhhhh sound. As you make this sound, slowly bring your hand toward your mouth. You will hear the shhhh sound change. What you’re hearing is the sound reflecting from your hand colliding with the sound leaving your mouth. This interference turns out to be one of the most important types of sound dimensions we use to echolocate objects at close distances.

But this demonstration is exaggerated. The interference patterns used for echolocation are usually too subtle to be consciously heard. This highlights one of the most amazing aspects of echolocation: It’s rarely experienced as sound. Try using your shhhh sounds to walk slowly toward a wall with your eyes closed. As you come close to the wall, you’ll experience its presence as more of a feeling than a change in sound. It may feel as if there are air pressure changes on your face, an experience also reported by the blind (echolocation was once called “facial vision”). Echolocation is truly one of your implicit perceptual skills: It allows you to detect aspects of your environment without even knowing which sensory system you’re using. And it could very well be that you’re constantly using the skill to recognize properties of the rooms you occupy.

Fascinating.