On Looking: Eleven Walks With Expert Eyes (19 page)

Back on Broadway, our own south-walking platoon weaved smoothly through the north-walking platoon, some forty persons strong, with nary a bang, a bump, or a jostle, defying the
HCM
odds.

“We don’t bump people,” Kent shouted over the crowd to me. He was reporting our experience at that moment—we were indeed unbumped—but he was also reporting what urban sociologists have discovered by eavesdropping on walker behavior. They were impressed: urban pedestrian behavior is quick and fluid—all the more impressive for being largely unconscious. Together we are doing a cooperative dance, a kind of pedestrian jig, without even knowing we are dancing.

When we walk in a heavily trafficked city, we adapt to being but a wee fish in a big pond by subtly adjusting our behavior in parallel with those around us. Fish happen to be a good model for our behavior: research on fish “traffic” management has led to the formulation of the few simple rules they follow to avoid congestion while moving together with hundreds or thousands of other fish. The same rules explain the remarkable synchrony of behavior in flocks of birds, as John Hadidian and I saw, as well as swarms of locusts and army ants, and mass migrations of wildebeest, whales, and turtles. Schools and herds execute impressively sharp turns; flocks gracefully swoop, soar, roll; and all groups pulse effortlessly around obstacles. Millions of army ants move together across the forest floor foraging for food, but their paths are never marked by the crowd-stopping congestion you see on a typical interstate highway at ten minutes past five in the evening. These group behaviors are especially impressive when we remember that some of these animals are exceedingly simple neurologically—insects, for instance, have no brain to speak of. While birds are much bigger brained, bigness-of-brain does not actually seem necessary for the behavior. Instead, all of these animals rely on three simple rules. The rules are these:

First,
Avoid bumping into others (while staying comfortably close)
. What counts as “comfortably close”—an animal’s “personal” space—will vary by species; what is similar for all animals is that if you follow only this one rule, it forces you to attend and react to the behavior of those in your vicinity. And that is the essence of what is called swarm intelligence: everyone must make movements that are sensitive to everyone else. The second rule:
Follow whoever is in front of you.
“Whoever” need not know where she is going: she may herself be following another. And so on and so on, until you reach the very head of the pack. Even there, the animal at the leading edge is neither leader nor sovereign. In flocks and schools, the role of leader is constantly changing hands. For only a moment will she determine the group’s direction. The final rule:
Keep up with those next to you
. Everyone must speed or slow with attention to those around them. This seems like an impossible calculation, until you realize how little effort you have to pay to walk next to someone else down the street, never once considering how you will be able to keep at the same pace.

These rules of “avoidance,” “alignment,” and “attraction”—keeping apart while staying together—are sufficient to explain all herd, school, flock, and swarm behavior. Artificial intelligence scientists have created animations of mindless “boids” programmed with just these rules: their behavior matches that of swooping sparrows and swarming ants.

And big-brained-and-busy human pedestrians. Sidewalk walkers follow the same rules. We try to avoid bumping, like other animals, though we do want to stay more or less together. We tend to follow others, and this leads us to form natural walking routes that become well peopled with people. While we do not settle exactly in someone else’s slipstream like fish do, we
hover,
preferring to look over the shoulder of the person in front of us instead of ducking right behind him. On a sidewalk, this tendency
sets up ever-widening-and-narrowing channels of walkers headed in the same direction.

One element Kent and I encountered that the swarm management teams do not is the simple fact of
other
swarms: there are always people coming the other way. Here the urban pedestrian has a special skill.

“It’s interesting how people from the suburbs get on subways,” Kent mused. “They come in as though they’re SUVs,” and they are immediately distinctive from the “native” walkers. They barge ahead, but this is not the way to smooth traffic flow, and crowds of visitors then clog a route or entrance. “
We,
who know the city, can kind of . . .”—and here Kent mimed a small movement out of the way of an oncoming walker.

He was doing the “step and slide.” If sidewalk traffic is dense and collision seems imminent, we pull this two-step pedestrian-dance move. While striding forward, the walker turns ever-so-slightly to the side, leading with his shoulder instead of his nose to turn the step into a side-step. We twist our torsos, pull in our bellies, and generally avoid all but the mildest brushes of other people (and if we do brush against someone else, we keep our hands close to our body and our faces turned away from one another).

This commonplace maneuver was identified after researchers watched untold hours of people walking past one another. Some of the more daring researchers also studied it by doing the walking themselves. They set out onto ever-busy Forty-second Street between Fifth and Sixth Avenues in Midtown Manhattan and walked back and forth, acting naturally but for intentionally
not
step-sliding out of anyone’s path. The people they inevitably knocked into clearly felt that the researchers had committed a small pedestrian violation by not doing their part to avoid the collision. In the seventies, when some of this research was done, the most common result was a mild imprecation or an indignant,
Whatsa matter—ya blind?
Even without knowing exactly what the rules are in order to avoid bumping each other, we sense at once when someone else is not following those rules.

Urban pedestrians make other small adjustments to others near us. When crossing paths with another walker, one party slows his pace just enough—maybe only for a fifth of a second—to enable both to keep the direction of their route unaltered. If someone behind us approaches quickly, we slide slightly to the left or right to give them space to pass. As Kent and I saw on the street, sometimes these accommodation behaviors are less subtle. Walking aside each other and approaching us on a part of a narrowed sidewalk was a couple holding hands. Expecting some full-body contact with them, I braced myself and continued forward. Unprompted, the male of the couple swung his partner in front of him, dancelike, to pass us single-file. Another man walking alone behind them stepped lightly into a tree pit to avoid us, leaving an imprint of his shoe in the dirt.

Even those who stop right in the middle of a sidewalk are accommodated. Whyte’s cameras noticed that people in the city (not just tourists) tended to stop to chat smack in the center of the flow of pedestrian traffic. People in the kind of conversation that obliges one to slow to a full stop—greeting a long-unseen friend, doing the final rounds of good-byes, or responding to someone’s surprising or serious comment by stopping outright—wound up squarely in others’ way. Oddly, the “others”—the walkers inconvenienced—navigated smoothly around them, shoals of fish opening and closing around a jutting reef. Perhaps the cameras were too distant to catch any imprecation muttered under their breath. More likely, the urban pedestrian, moving toward his destination, simply steers around stoppers as he would nonhuman obstacles: no one chastises the lamppost for being in his way.

One reason all of our step-sliding, pedestrian-jigging works
is that we are regularly
looking
—ahead and at each other. We do not just look to see who is there; we constantly, steadily look to calculate how we need to move relative to those around us. We regularly turn our heads back and forth, to the left and right, surreptitiously peeking at who is behind us or to our sides. When our heads face forward, we survey the scene ahead of us. Our eyes make small saccades. Within a long oval projecting forward from our feet to about four sidewalk squares ahead, we quickly note the direction and pace of anyone headed our way. We also glance at others’ faces, which tell us if they are likewise looking forward into their own long ovals (and whether they are reacting to something surprising or alarming that might be behind us). There is
information
in the angle of others’ eyes and the turn of their head. Most of the time, people are looking where they are going: gazing straight ahead. But they begin actually
inclining
toward their destination when it is in sight. Should someone seem to peer over to the doorway of the building down the block, more likely than not, he will walk there directly. Or just follow his head: we all make anticipatory head movements when we are going to turn a corner. Our heads lead our bodies by eight degrees and as much as seven steps, as though all in a hurry to get around the bend. Watch a walker’s head and you can predict his path down to a single step. We learn this without anyone teaching us, and without knowing we know it.

The importance of this “looking” in the success of the dance comes into play with the relatively new species of pedestrian on the street: phone talkers. Their conversational habits change the dynamic of the flowing shoal. No longer is each fish aware, in a deep, old-brain way, of where everyone is around him. The phone talkers are no longer even using their fish brains: they have turned all their attention to engaging with the person on the phone. They block out their sense of someone walking too close; they fail to look into their walking ovals and step-slide out of the way. They no longer follow the rules that make walking on a crowded sidewalk go smoothly: they do not align themselves (they swerve); they do not avoid (they bump); and they do not slip behind and between others (they blunder). They stop minding the social convention to stay to the right, and weave across lanes of traffic. Texters are as bad or worse: they fail to even move their heads before turning, since they are slumped over to monitor their texting thumbs. I fantasize that the phone talker’s route, if reconstructed and synchronized with their conversation, would reveal the organization of the chat: straightforward questions-and-answers matching straight, forward walking; sidetracking and topic-changing marked by weaving and divergent walking.

 • • • 

Notably, not
all
of our crowd behavior mirrors the animal swarms. Mormon crickets and desert locusts seem to cooperate marvelously, march-stepping in the same direction in caravans miles long. But they are not just cooperative; they are also cannibalistic. Cooperative, streaming swarm movement can also be generated, it turns out, if you are trying to eat the animal in front of you while avoiding being eaten by the animal behind you. Thus the double-takes seen when a foot race comes through a neighborhood not expecting it: whether the racers are running
together
or
away
from one another is not obvious from the simple fact of their speedy running.

Some desert locusts also have a gregarious side, which is useful in swarming. And there is a neuropsychological mechanism that may explain what prompts the lowly locust to seek company. Their gregarious behavior correlates with a huge increase in the amount of serotonin in the central nervous system. In humans, serotonin is involved in many behaviors, including moving in a group. Some of the most common contemporary antidepressants modulate the action of serotonin by increasing the amount of it lying around in our brains. One could speculate that a rise in serotonin also allows us to be sensitive to—and, for some of us, to feel rewarded by—moving smoothly in a swarm of our own species.

 • • • 

Emerging from our platoon on the next corner, I looked over at Kent. His head was just turning to look across at the other, westerly side of the street. I took that as a request. With a small adjustment of my path we crossed the street together without exchanging a word.

I should note: we crossed the street—but not at its corner. Every good New Yorker makes herself known in foreign cities by doing what we just spontaneously did: we jaywalked, crossing the street in its middle. As we were crossing, I looked up into the cab of a truck turning onto the street, aimed right at us. In response, the driver chose not to hit us and slowed to a stop.

A couple of classic street-scene events had just occurred: one historical, one psychological. Historically, we continued the proud urban tradition of walking wheresoever we pleased.
Jaywalking
was first used a century ago to describe the behavior of a pedestrian unaccustomed and naive (a
jay
being a silly person) about how to walk safely in a city. It was among many terms of mild
opprobrium used about bad walkers. A
New York Times
article from 1924 includes “the veerers who come up sharply in the wind and give no signal,” “the runners who dash to a goal and then dash back again,” “the retroactive, moving crabwise,” “left ends and butters,” “the plodder,” and “those who flee and turn swiftly” among those who deserved equal blame for the chaos of the streets and sidewalks at the time. “Jay driver,” though suggested by many jaywalkers who saw the speedy driving of the new auto menace on the streets as the real hazard, never caught on.