Turn Sounds Around
- :Valerie Hutchens
By Valerie Hutchens
When my dog barks, I know whether she’s at the back door or at the front door. I don’t have to be looking at her. I can tell which direction the sound is coming from without seeing her at all.
Many people have had the same experience. How does our brain locate the source of a sound?
A person’s ears are not very far apart, but that short distance makes it all possible. Every sound hits each ear a little differently. A sound on the right goes directly into the right ear, but it must travel around the head to reach the left ear. The left ear receives that sound an instant later than the right, and the sound in the left ear is a bit softer.
Ever since the day we were born, our brains have been learning to use these small differences to locate the sounds we hear.
If you reversed the order of the sounds coming into your ears, would your brain know where the sound was coming from? The “mirror ears” shown above can turn sounds around in just that way. When you hold the ends of the tubes in your ears as shown, they make the sounds from each side go into the opposite ear. (They may work better for high-pitched sounds.) Follow the illustration to make your own “mirror ears,” and listen for yourself.
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