Sometimes, the sense of hearing is a mixed blessing. Think of the pleasure you feel while listening to your favorite music. Consider the comforts of a heart-to-heart talk with a parent or close pal. On the other hand, imagine the horrible noise of an ambulance screaming along the highway, or the terror of a strange sound when you’re almost falling asleep. Pleasure, comfort, pain, and terror—you experience them all through your ears.
The human ear can hear a wide range of sounds, from the bone-jarring assault of a jackhammer to the whisper of wind in the leaves of a tree. But there are sounds that you can’t hear, like the high-pitched whine of a dog whistle. And you never hear most of the sounds your own body makes: the creaking of your joints, the churning of your stomach, the fluttering of your eyelids. Your body has a mechanism that screens out its own sounds so you can tune in to what your brain is really interested in.
