As a Yale undergraduate, I lived for four years in the shadow of Harkness Tower, a nine-story gothic spire housing one of the largest carillons in the Western Hemisphere. For two of those years, my rooms were located in the courtyard directly below it. In the spring of my senior year, a friend managed to get his hands on a key to the tower, and a group of us sneaked up it very early one morning. A winding stone staircase led to a cavernous bell tower, and from there we climbed rickety spiral metal steps toward the summit.· The massive bells, some as tall as a man, were hung in rows on every side.· The largest of the 44 bells, a seven-ton monster cast by an English foundry nearly a century ago, was reportedly modeled after Big Ben in London.
You would think my attention would be riveted by the tolling of those bells. But no. I quickly grew accustomed to the twice-daily carillon concerts and rarely paid them any heed, except when visitors commented on them in my presence.
I was reminded of this recently when the Providence and Worcester Railroad resumed daily freight service on tracks that are just around the corner from my street. I live on a cul-de-sac off a sleepy country lane in a small New England town along the Connecticut River. It is normally pretty quiet here. But when a big train rumbles through, you can sometimes feel your house shake from a block away. The railroad crossing around the corner does not have gates, so the train announces its approach with a sonic blast that might plausibly herald the Second Coming. This has been going on for some weeks now, but already I notice the trains are becoming mere background noise, barely registering in my awareness. What’s going on here?
In evolutionary terms, there are obvious advantages to being able to tune out random background noise and to focus on sounds that might improve your chances of survival. As it happens, all mammals come equipped with specialized neurons in their brainstems that can direct attention to unexpected sounds while suppressing routine ones. At a time when humanity’s place atop the food chain was not yet secure, these “novelty detector neurons” could filter out the sound of the wind in the trees while zeroing in on rustling noises that might signal the presence of predators or prey. Today these same neurons alert mothers to a crying child in a distant room over the blaring of a nearby TV or enable listeners to zero in on a single voice in a crowded room -- a phenomenon known as the “cocktail party effect.”
“Selective auditory attention” is the term neuroscientists use to describe our ability to focus on certain sounds while ignoring others. Without it, our attention would quickly become entangled in the many sonic encroachments of modern life. It is one thing to live on a cul-de-sac on the quiet end of town and have to contend with nothing more intrusive than the hum of insects in the summertime (plus an occasional freight train rumbling through). It is quite another to stand on a busy Manhattan street corner, where the noise level can rise to 70 decibels or more – loud enough to damage hearing with prolonged exposure. How do you hear yourself think, much less carry on a conversation?
There are precious few places left in creation where you can truly hear yourself think. According to acoustic ecologist Gordon Hempton, there are only about a dozen wilderness areas in the U.S. where silence still reigns. By silence, he does not mean total quiet but rather no man-made noise that drowns out the sounds of nature. As Hempton expresses it, “Silence isn’t the absence of something, but the presence of everything.”
Hempton recalled how he first decided to become an acoustic ecologist, which didn’t even exist as a field when he embarked on his life’s work. He was driving from his home in Seattle to Madison, Wisconsin, where he was pursing a graduate degree in plant pathology at the University of Wisconsin. He pulled over to sleep in a cornfield and was awakened by a thunderstorm. “While I lay there, and the thunder echoed through the valley, and I could hear the crickets, I just simply took it all in,” he remembered. “And it’s then I realized that I had a whole wrong impression of what it meant to actually listen. I thought that listening meant focusing my attention on what was important even before I had heard it and screening out everything that was unimportant even before I had heard it.”
According to Hempton, focusing one’s attention only on sounds we regard as important is actually a form of “controlled impairment.” For him, acoustic ecology is really nothing more than a quest to become a better listener. And that involves unlearning a lot of the habits we acquire with help from those novelty detector neurons. Hempton recommends spending time with a small child who has not yet been schooled in how to “pay attention,” as adults might define it. “Hoist them onto your shoulders and go for a night walk,” he advises. “They’ll tell you everything you need to know about becoming a better listener.”
Over the past decades, Hempton has circled the globe in search of pristine sonic environments that he can record before their unadulterated natural sounds are lost forever. He acknowledges that finding yourself in such a place can be daunting. To a large extent, man-made noise is our preferred habitat. Silence may indeed appear at first to be the absence of something. In my experience, being in a place where you can hear yourself think is usually a prelude to your thoughts falling away as well. And once your thoughts have disappeared, so do you.
“Silence and the Presence of Everything,” On Being with Krista Tippett, May 10, 2012