Part 9 (1/2)
Sounds are also contagious, whether they are emitted by a living thing or a simulacrum. The sound of someone breathing heavily in a movie can affect your own breathing rate. A commercial jingle is successful if it lands in your head and stays there, replaying itself unceasingly. You may not want a c.o.ke or a mattress or a pizza right this second, but the suggestion has wormed its way into your subconscious in case you grow thirsty or sleepy or hungry. And the contagion of sounds has a biological component: if a predator growled at our ancestor's ancestors tens of thousands of years ago, his insides likely vibrated to this growl, and he hightailed it away from the scene. Today, if my son, recently an infant, cries, I feel it viscerally. I can locate no anatomical mother-b.u.t.ton he is pus.h.i.+ng, but I react as though there were one. It is as if he cries at a frequency that makes my interiors rumble-and I hightail it toward him.8 I can tolerate the sounds of my son's cries, but the sounds of other people's cries, as well as most sounds shared in a city, have made generations of urban dwellers first cringe, then fume, and then, finally, form Quiet Leagues, Anti-Noise Campaigns, and Noise Abatement Commissions. As early as 500 BC there were complaints about the noises of animals working (elephants trumpeting, horses whinnying) and men playing (gongs, drums, or just making merry). By the seventeenth century in London, the complaints began to find their organized center. These afflicted urbanites were subjected to not just babies but also street criers hawking their baskets, beans, bells, cabbage, eggs, or flowers to anyone within earshot. Chimney sweeps, chair menders, and tinkers hollered notice of their services; dogs yelped, roosters awakened, and street musicians added musical insult to auditory injury. Parliamentary action was taken against the musicians and their ”devious and hurtful” sounds. By the turn of the twentieth century, New York City had joined the din against the din. The din itself had changed: no longer was the urban soundscape full of noisome animal sounds; machines had overtaken them. The polemics against noise cited the incredible cacophony of engines revving, honkers honking, pneumatic drills, pile drivers, and wheezing trucks. This was on top of the people playing piano poorly inside and saxophone poorly outside. All the singing, crying, rattling, whistling, thudding, slamming, ringing, rasping, and alarming was bad for health and for habitation.
By the time Lehrer and I finally left our position on the corner, my ears were well nourished, stuffed full. I had almost stopped listening to the city, and that may be why, when Lehrer was saying, ”. . . like that siren we heard over there,” I was struck. I had heard no siren. How I could have missed one of the noisiest features of the urban soundscape is beyond me. What Lehrer was describing partially explained it, though: the way the city sounds simply is not the sum total of the sounds in it: ”You know, we can't really record that [siren sound] because if you recorded the siren so far away all this other, closer noise happens,” crowding the sonic scene. ”If you record the siren closer, you get a clearly defined sound. But then if you just take that and put it into your soundscape when you're making an environment, it sounds wrong.”
In the real world, the sound is reverberating in a particular way based on the structures it is pa.s.sing; the sound arriving at listening ears is changed depending on what lies between the ears and the siren. The pitch and loudness may seem steady, but they are changeable, and they are different if the listener is a block or three away. The Doppler effect will be different based on not just the speed of the ambulance bearing the siren, but on the direction of your movement relative to that ambulance. Viewed this way, every moment of listening in a city is unique, a sonic landscape painted for the moment and then washed away.
Even temperature changes our perception of sound. It is not our ears that are changed, nor the sounds themselves (for the most part), but that different temperatures control how far and where sounds will travel. Perhaps you have a memory, held in your body as much as in your head, of being outside in the wilderness, in a wide open area, the sun beating down on you-and experiencing an intense silence. Or, relatedly, on a clear night outside, hearing distinctly what is going on in a tent three campsites away. Lehrer's siren carriers farther on the city's coldest days, when fingers are balled up in mittens and footsteps clop loudly on sidewalks.
We can turn to the sound-making habits of animals to explain what is happening here. Natural selection naturally selects the animals who send signals to their potential mates that can be most clearly received: so, in many cases, evolution favors those who intuitively know how to best send a sound signal through a medium-say, air or water. Not all air (or water) is alike: often it forms a kind of layer cake, in which each layer is at a different temperature or a different pressure. For instance, as you dive deeper into the ocean, the pressure steadily increases: the greater depths have a much higher pressure than the shallower waters. On land, each night the earth cools, and in the morning the radiated heat makes the ground cooler than the sky: here, the lowest layers are cooler than the higher layers. We can think of the layers as having certain ”sound speeds”-speeds at which sound can travel.9 It turns out that sound travels more slowly in warmer air (or lower pressure) and faster in cooler air (or higher pressure). If the sound is traveling along a cool layer and there is a warm layer above it, the sound will spread into it and diffuse. On the other hand, if the sound is moving through a warm layer and there is a cool layer nearby, it will continue to travel along that warm layer, which now channels the sound farther before it weakens and fades away.
This is why you will hear the most birds singing at dusk and dawn. After a cold night, when the earth is chilled, the ground layer is cool and the layers above the treetops are warmer: a temperature inversion from the ordinary arrangement of the ground feeling warmer than the air. A bird singing at dawn can send his tuneful song traveling much farther along the treetops than it otherwise would. This is good news for singing birds, who are hoping to reach as many other bird ears, especially of the female variety, as possible. Likewise, few birds sit around on the ground calling to one another in the middle of a sunny day, and temperature is again the cause. In a warm layer of sound, their calls get scattered every which way. The message they are sending to the bird a skip and a jump away may not even reach them, the sound disappearing into the ether.
Similarly, there is a fine whale radio channel in the ocean-in a layer of ocean. The layer sits at about a thousand meters below sea level in the North Atlantic, where the pressure is not yet too great and the temperature is not too cool. This allows for long-distance sending of sound signals, on the order of miles, channeling the sound horizontally to distant whales' waiting ears. Some twenty hertz sounds made by fin whales, who live in deep water often under ice fields, are speculated to travel for hundreds of miles. Though these whales are highly social, they are also often quite well dispersed, and make these low-frequency sounds to keep in contact with one another. Their calls could travel even farther but for interference from other sounds made by other whales, the ice itself, or, increasingly, by human beings-from s.h.i.+p traffic, undersea explosions, and Navy sonar.
If sounds travel differently along temperature channels, the seasons of the year could also be considered to be separate channels changing sound perception. After a big snowstorm, the city is noticeably quiet, the snow s.n.a.t.c.hing the din and burying it under its chilly cloak. Packets of snow occasionally flop noiselessly from lamppost heads to the ground below. Few cars roam the street, except the snowplows grittily sc.r.a.ping the asphalt under their wheels. Boots squeak as they carry the weight of bodies over a sidewalk of snow.
My footsteps, quiet in sneakers, were reflecting the spring. We descended the stairs at a subway entrance-the very subway that had rumbled below us earlier. Before Lehrer and I said our good-byes, we lingered in the anteroom of the subway, struck by the sheer number of noises in the s.p.a.ce: the clunk of the turnstiles, the snippets of quickly pa.s.sing conversation, broadcast announcements accompanied by impressive static. When a train actually arrived, it brought its own reverberant broadband rumble, the squeak of its brakes, a swarm of noisemaking commuters, and the whirr of its accelerator. Those entering the station yielded to those leaving, and then the tide turned again. Turnstiles dinged at a prodigious rate, recording the paying fares.
”No one bothered to make that consonant at all,” I reflected, listening to the different turnstile tones overlapping.
”Minor second,” Lehrer responded in a flash, describing what we were hearing. He whistled it. ”People don't like the minor second.”
There is a solid scientific basis for this aversion. The pitch of a sound is its most audible frequency of vibration, but that particular vibration is just one of many produced at the same time with any sound. A note played on a piano, for instance, may be heard as one note, but it ”includes” many other pitches that help make up the sound we hear. An experienced musician may be aware of these pitches; the rest of us are likely not. The series of pitches hidden within one note are called overtones, and they correspond to other notes on the piano. Hit a middle-C and it vibrates at 262 hertz most loudly. But the note at 524 hertz, the C an octave up, rings out as well. This hidden vibration is the first overtone. The fifth, a G, is next, followed by the fourth, the major third, the minor third, and so on. You might not hear these overtones, but you are surely aware of them: an octave sounds pleasing to our ears, as does a fifth or a third. When one gets to the outer borough of the overtone sequence, though, the sounds are more dissonant. The minor second is well in the outer boroughs. Similarly, the tritone, an augmented fourth or diminished fifth, is so dissonant and unnerving that it was thought to be the work of darker powers, and it came to be called diabolus in musica, the ”devil's interval.” In the Middle Ages it was prohibited in music.
I wondered if this minor second was having any long-term psychological effect on the transit workers stuck in the underground booths.
One of the old uses of the word silence netted and pinned forever to the page in the Oxford English Dictionary is the nineteenth-century's ”a want of flavour in distilled spirit.” I thought of this that night as I sat down to listen to the audio recording of my walk with Lehrer. Back in the silence of my office at home . . . wait. There was not silence but relative silence. I knew that a few blocks away, a highway hummed. There were regular sounds of apartment living coming out of the back windows my office overlooks. Clothes languidly swished in a warm-water cycle nearby. And the sounds of the day left a ringing in my ears, representing all the sounds we hadn't heard outside. Our brains make sound out of silence. Noise seems to be the flavor we are designed for.
As I transcribed the recording I made of our conversation on the walk, I was struck by all the noise the recorder, with its high fidelity and indifferent attention, picked up that I had missed at the time. It captured and preserved its own rhythmic banging against my leg as I strode. It noticed my sniffing, an indication of the chill I was collecting as the walk went on. I was surprised to hear on the tape how often the wind rode in to wash out any other sounds. Once, the curls of a laugh rose above it; other times, it erased everything else. I listened for any extraneous sounds of Lehrer: snapping snaps, sighs, a whistle while he inhaled. He was silent. At the end of the tape, we said our good-byes, and the sounds of the city swallowed him up.
Taking a walk entirely for the purpose of listening, I had still missed many sounds. But something else had happened. What I heard had morphed from noxious urban noise into being the characteristic, flavorful clatter of my city. I enjoyed the roar of traffic and the buzz of flies; I looked at pigeons hoping they would coo; I stared down pa.s.sersby, silently egging them on to hum or cough. I counted squeals and squeaks and squawks and measured them against whines and whistles. Each sound felt invited, a pleasure. Welcome, sound.
1 Hertz (Hz) is the standard measure to describe the pitch at which we hear a sound. Sound is simply a wave of pressure moving through s.p.a.ce; the number of hertz indicates the number of those waves per second. The higher the hertz, the higher the sound we hear.
2 And what of giraffes? One might get the idea from children's literature that giraffes are silent. Not only do they whimper and grunt, but giraffes also emit an infrasonic, low-frequency sound when they ”neck stretch,” reaching the neck back over the body, and when tossing their heads up and down.
3 Alas, sometimes one hears less, too: not only does hearing loss occur naturally with age (by this writing I have lost ability to hear the top 6,000 or so hertz of my original hearing range), but it occurs with exposure to any sound at all-even at nonSpinal Tap levels.
4 Named for Alexander Graham Bell (his second l lost to history) for his role in sending sounds across telephonic wires to waiting ears.
5 Among the many reasons to appreciate bats, this one stands out: bats are the primary responsible parties for our not being eaten alive every day by mosquitos.
6 I have read, but not heard, that their pulsing rate quadruples with each degree centigrade the mercury rises.
7 Ultraviolet light is visible to many other animals. Plenty of bees and birds, for example, use the reflection of ultraviolet light to find food (reflected off a bull's-eye around the stamen in the center of a flower) or a good mate (whose feathers may reflect more UV light if the animal is healthy).
8 Indeed, some research using fMRIs found that two areas-the amygdala and the ventral prefrontal cortex-in the brains of parents grow more active at the sound of an infant crying. Not so nonparents, whose brains showed a bigger response to laughter than to crying.
9Sound is always the same kind of stuff: compression waves propagating through a medium, causing particles to hand off the vibration to their neighbors. We hear these waves as pitched higher or lower, or as being more or less intense-but they can also travel faster or slower. Counterintuitively, while sound moves at around 1,100 feet per second in the air, it races along at somewhere on the order of 5,000 feet per second in water. Though water is denser than air, which slows down the pa.s.sing of the waves through the water molecules, it is also stiffer than air, which speeds up the sound. Sound pa.s.ses through solids, which are stiffer still, at fifteen times the rate as through water.
”The only true voyage . . . would be not to visit strange lands.
but to possess other eyes, to see the universe through the eyes of another, of a hundred others, to see the hundred universes that each of them sees, that each of them is.”
(Marcel Proust).
A Dog's-Nose View.
”A beagle pulling on a long leash trotted by and unceremoniously defined the corner of the trash pile by urinating on it.”
This entire project sprang from a walk with a dog; it seemed apt that it end with one. I spent sixteen years walking with (and informally studying) Pumpernickel, a curly haired, sage mixed breed. Through her choices, the subjects of her attention, what she balked at or lunged toward, I began to see her world. By minding her attention, seeing what she saw from two feet off the ground, and observing how much she seemed to smell her way through the world, my own perception was changed. I began to see how horrible a long block with no trees or lampposts was: where could one receive word, through the markings of other dogs, who has been around? Where could one leave word oneself? Despite my never once attempting to communicate with others by peeing on the street, I picked up Pump's aesthetic preference for streets with a lively set of street furniture, trees, and other curbside paraphernalia.
During her life, we developed a wide variety of walks together geared to what I imagined her view of the world to be. There were into-the-wind walks, during which she kept her eyes closed into slits and her nose in the air, nostrils working mightily. We took smell walks: instead of racing to take a walk defined by me for its length or its destination, we loitered at every place she wanted to smell, as she inhaled her view with her nose. As she grew older, we took walks that were largely episodes of sitting, in a field with ample olfactory vistas and plenty of dogs upwind. Most dog walks are done to allow the animal to pee or to get exercise. While those are sound reasons for a walk, what about walks to see the world? To interact with other dogs? What about walks to smell new smells?
Because humans are not smell-centered, we have difficulty imagining how rich in odors the world is. That is a constraint of our eyes: the picture they paint is so vivid that we a.s.sume there is no other way to make sense of the world but as a series of things to see. For most other terrestrial mammals, though, on four legs and with their noses near the ground, the world is perceived through odors. Kenneth Grahame, in The Wind in the Willows, introduces the genial Mole to school us: ”We others,” he writes, ”who have long lost the more subtle of the physical senses, have not even proper terms to express an animal's inter-communications with his surroundings . . . and have only the word 'smell,' for instance, to include the whole range of delicate thrills which murmur in the nose of the animal night and day, summoning, warning, inciting, repelling . . . those caressing appeals, those soft touches wafted through the air.”
Mole must lead us stump-nosed, blunt-seeing humans to imagine what it might be like to ”see” in this way through metaphors: metaphors from sound (murmur), tactile sense (appeals, touches), and evocations of emotion (thrills, inciting, warning). We can come up with a vivid description of how a place we visited looked; but how it smelled? We are left with vague comparisons (”like a summer's day”) that are evocative but not specific; names that tell us nothing about the quality of the scent (the smell of garlic or fresh bread); or superficial quality words (foul, lovely, delicious, spicy). What smells are very good at is beckoning memories forth: a whiff of pipe tobacco reminds me of the smell of the inside of my father's desk when I was a child and he was still a smoker, of the sound of his footfalls and the jangle of the change in his pants pockets, of what it felt like to have him listen to me and smile. The smell, like the memory, is entirely personal. It cannot be shared with the ease that an image, rendered in ink or oils, can be experienced by hundreds or millions of viewers.
By now, it is well known that dogs are ”good” at smelling. As we humans open our eyes and see the world, dogs come out of sleep with both nostrils working. A dog's nose is remarkably well made for this task. The inside of the nose is a labyrinth of tunnels lined with specialized olfactory receptors waiting for an odorant molecule-a smell-to land on them. In the back of the nose is an ”olfactory recess” separated from the main respiratory pathway by a bony plate, allowing smelling to be distinct from breathing, and letting odors loiter for a long time to be considered. Though we tend to think that only some things are smelly-a spring bloom, a trash can, a new car, a bus's exhaust-just about everything has a scent. Anything with molecules that can be ”volatile,” that can evaporate into the air and travel toward a receptor in someone's nose, smells.
The dog nose has hundreds of millions of receptors in that nose; they even have a second kind of nose above the hard palate of their mouth, called a vomeronasal or Jacobson's organ. Molecules such as hormones that do not stir the receptors of the nose to fire may find a rousing welcome here. All animals house hormones, which are involved in bodily and brain activities, and those hormones we emit, called pheromones, are detected by the vomeronasal organ. This is how a dog could detect another dog's stress or s.e.xual readiness in a spray of her urine left on the ground.
Dogs are called macrosomatic, or keen-scented, while humans are called microsomatic, or feeble-scented. It is not for lack of equipment, though: almost 2 percent of our genome, the entire blueprint for making a human being, is dedicated to coding for olfactory receptors. Think of it! One out of every fifty genes is committed to making cells that can detect smells. So smells are important to us. Without smells in our lives, we become desperately unhappy-foods are not enjoyable, the environment is flattened-while some smells bother us excessively.1 But for much of the day, we go about our business un-smellily: we do not smell overmuch. For humans, odors tend to be either enticing or repugnant, alluring or foul, evocative or evaded. To a dog, the world is terrifically smelly-but not in the way we think of smelliness. To the dog, smells are simply information. Their world has a topography wrought of odors; the landscape is brightly colored with aromas.
Biologically, the human nose works in the same way as the dog's. Odors are swept into the far reaches of the nose and land in receptors-a few million of them. But that is hundreds of millions fewer than the dog bears.2 The difference in number of cells translates into a difference in kind. Dogs detect odors at one or two parts per trillion, unimaginably more sensitive than we are. One part mustard, one trillion parts hot dog: dogs can detect the mustard.
To begin to understand what a city block really smells like, there seemed to be one clear course of action: ask a dog. So it happened that one day I set to taking a walk around the block for this book with Finnegan, the earnest, playful black dog in our home now. I began by asking Finnegan about his interest in accompanying me, in showing me the odors of our block. From the way he was plopped languidly on the sofa, head relaxing off its edge, he did not look inclined. But on my second request, he leapt up, consented to having his leash snapped on, and trotted out our door alongside me.
Finn pushed out into the fresh air with enthusiasm. I followed him. Then we . . . stopped. It had occurred to me to ask his preference in our walking route, so instead of pulling him left (parkward) or right (cityward) when we exited the building, I stopped on the steps. Finn, ever cooperative, stopped as well. He perched on the top step, projecting his snout proudly ahead of him. As a steady, light stream of people walked by, they pushed air out of the way as they pa.s.sed, occasioning plenty of sniffing by Finn. If someone so much as turned in his direction, he ducked his head and let his tail wiggle his body with antic.i.p.ation and excitement.
I waited for him to make a move. Between pa.s.sersby, his body was still, only his head reacting to the activity on the street. The day was especially windy, and a sad old flag on a building across the way whipped around its pole. Finn perked his ears at the snap of the cloth, the bang of the flag rope against the pole. A sound Scott Lehrer could use for a shot of a seaside New England cottage hit by an ocean breeze, I thought. Our urban wind carried the sounds of someone hollering down the block, and tumble-weeded a plastic bag, belly full of air, along the tops of the parked cars.
We stood on the steps for several minutes. At last, I realized that should I not start us moving, we would not be having a walk at all, but a rousing ”stand.” Were Finn any other kind of animal, he might have bolted as soon as we got outside. So I chose a direction and began walking. As we set off, I watched Finn's attention. My audio recorder was again useless here, as it had been with my son. Instead, I would have to let Finn tell me what he saw by observing where he went, where he loitered, how his ears bent into focus, and how his tail measured his mood.