We live in a sonic world, immersed in vibrations that stimulate microscopic hair cells deep inside our ears. This unseen energy influences our mood, our learning, even our health. We experience it as comforting music, as information-laden speech, or—all too often—as irritating noise, a by-product of our increasingly mechanized world. Despite all the ways sound affects us, we often let it slip unnoticed into the background of our lives. Hoping to understand it better, I set out to explore the mysteries of sound in the course of one day.
At 6:50 a.m., my alarm clock begins the assault on my ears as the groggy gray matter between them is rudely yanked toward consciousness. My eyes shoot open, and as awareness slowly crystallizes, a single idea crowds out all others: Make the noise stop. My right hand knows just what to do and immediately puts an end to the awful blare.
The formal term for the unpleasant shock that jolts me awake is acoustic startle response. Loud, sudden noises can trigger movements involving the limbs, torso, and eyelids, as well as increases in heart rate and blood pressure. This stress reaction comes in handy when noise indicates danger from, say, a wild animal or a deadly explosion. It is less useful when the enemy is a clock.
