On Looking: Eleven Walks With Expert Eyes (16 page)

Raccoons are not only widespread but also long lived for urban
animals. Hadidian followed the first animal he radio-collared for thirteen years. For the time it takes a child born in the city to learn to sit up, to stand, to walk; to say simple words, complex words, to talk, to talk back; to text, to do algebra, to play a tune on the piano—during all that time, he may have been quietly accompanied by a raccoon living a parallel life (with less algebra) outside, within a block of his home.

As I looked around me, seeing no raccoons but all the places they might be—in twelve hours’ time—I spied a charming brass lion’s head at eye level along a granite wall. One cannot help but notice that it is never a handsome raccoon’s head emboldened in brass as a knocker. But raccoons have these leonine ways, and are at least as charismatic (and less predatory on humans, to say the least). If the city were overtaken with lions, instead of raccoons, I wonder if we would feel the same way about them.

 • • • 

We had been walking for blocks, and apart from evidence of squirrels past and raccoon accommodations, the only animals I had seen were ones dressed in puffy black parkas and snow boots. I asked Hadidian if we would have to come out at night in order to see the real wildlife of the city.

“Well, we’ve heard some house sparrows, saw one starling, saw a big flock of pigeons. . . .”

What? This was news to me. “You should tell me about this!”

I smiled, abashed. Even when looking for animals, I had missed them. All three birds are ubiquitous. Our starlings are famous—not for their great iridescent coloration, or even the peek of bright blue on the beaks of the males, but for their being an ecological disaster. “They were brought over [to the U.S.] by a fellow named Eugene Schieffelin who wanted to bring to North America every bird that was mentioned in Shakespeare,” Hadidian
added. Starlings make their appearance in
Henry IV.
“Nay, / I’ll have a starling shall be taught to speak / Nothing but ‘Mortimer’,” says Hotspur—evidence that Shakespeare knew of the starlings’ ability to mimic speech. Clever birds—so clever, unfortunately, that they wreaked havoc on their new environment. Before they proliferated, according to Hadidian, “most of the birds of the eastern U.S.—maybe thirty-four hundred species” traveled through countryside that became Manhattan.

How had I missed these birds? It had to do with how I was
looking
. Part of what restricts us seeing things is that we have an expectation about what we will see, and we are actually perceptually restricted by that expectation. In a sense, expectation is the lost cousin of attention: both serve to reduce what we need to process of the world “out there.” Attention is the more charismatic member, packaged and sold more effectively, but expectation is also a crucial part of what we see. Together they allow us to be functional, reducing the sensory chaos of the world into unbothersome and understandable units.
²
Though we think of expectation as a cognitive experience, the process actually operates on a single-cell level, and even within the sensory organ. Consider it from, say, the eye’s vantage. A stimulus hitting the cells of our retina could be one of many things. The eye is agnostic about what it is: a toy car held on the palm of your hand looks the same to the eye as a real car seen from a distance out the window of a building. But we never confuse the two. It is context (am I holding this car or looking out the window?) that allows us to resolve the ambiguous pattern into “matchbox” or “bona fide.” That’s expectation’s doing.

Attention and expectation also work together to oblige our missing things right in front of our noses. There is a term for this:
inattentional blindness.
It is the missing of the literal elephant in the room, despite the overturned armchairs, dinner-plate footprints, and piles of dung. Psychologists have cleverly demonstrated our propensity to miss a rather obvious element of a visual scene when attending to another by asking subjects to watch a specially designed short video. In this video, two teams, dressed in white or black shirts, toss around a basketball. The task is to count the number of tosses made by one of the teams. That is the expectation: the viewers expect
there’ll be basketball-tossing
! They gear up to see it. Afterward, the subjects are asked for their final tally.
³
Of course, this is not the actual question of interest to the researchers. That question is this: Did you, attentive subject, notice anything else? Anything unusual? Anything else . . . at all?

Nearly half of all subjects did not. In this case, the elephant in the room is an actual gorilla—well, a person in a gorilla costume—who waltzes right between the players, pounds his chest, and saunters off-screen. Paying attention to the basketball players, we miss a rather salient (and furry) figure among them.

Expectation also allows us to miss bits of the ordinary world, not just the gorillas in our midst. Indeed, it nearly prevents us from seeing lots of things happening around us. In an economic move, rather than try to process everything we see, our eyes stop spending time taking in information from those parts of the environment that hold steady. Staring at your computer screen, or the book in your hand, your eyes quickly stop processing all of the details of the monitor or the corners of the pages in depth. If something changes, sure, the eye darts to it and neurons fire away. If nothing changes, those neurons can go quiet. In this way, expectation suppresses activity in the sensory system. This is usually
not only unproblematic but helpful: by limiting our perception to what is likely, we see what we need to more quickly and reliably. A carriage horse wears blinders to restrict his visual world physically, since carriage drivers long ago learned of the inefficacy of simply asking the horse nicely to
Please focus on what’s straight ahead, never minding that cute filly to the side
. People who perform highly unusual and difficult memory feats—memorizing thousands of digits of pi, for instance—may wear goggles or headphones to block distracting sensory information from interfering with the parade of numbers in their heads.

Blinders and goggles are ways of physically restricting what you can, and expect, to see in the world; the brain has its own internal mechanism. By thinking about what you are looking for, or anticipating what you might be looking at, your brain grows biased to see it: biologically, the neuronal processes are primed to spot objects that fit your expectation. The object does not need to be simple: think about a face, and you enhance activity in special brain cells that process faces—leading to seeing the face faster and more clearly than you otherwise would have. This, combined with the “search images” that helped Charley Eiseman find the insect tracks invisible to me, enables us to transform the world: expectation magically sorts the world into things-we-are-looking-for and things-we-are-not.

This phenomenon of expectation was discovered through a simple test called the “cued-target detection task.” It is a very boring version of a war-games video game. The player is asked to press a button when he notices a target pop up: some simple thing like a flashing light or a triangle on the screen. On different rounds, there will be different cues to where the target might be: sometimes an honest cue, which appears right where the target will be; sometimes a misleading cue, which appears clear across the screen from the target.

Unsurprisingly, the honest cue helped people respond about twenty-five milliseconds faster to the target than the misleading cue.
⁴
But in either case—whether the cue is misleading or not—people simply saw the target faster with a cue, because they knew to expect it. The effect is mediated by various neurotransmitters, which start rallying neurons to fire earlier than would otherwise happen.

And we do not
expect
to see animals in the city. So we for the most part do not. If we notice things faster simply by expecting them, then looking at the world as if it holds “cues” for us just might work. I endeavored to test this theory at once, with urban wildlife in mind. My gaze fell on a well-graffitied wall to my left. It encased a schoolyard, full of young, shin-guarded soccer players, prancing around on Astroturf. The wall seemed hardly worthy of careful examination, but with my heightened keenness for signs of animals, I felt there was
something
there. A small, uneven piece of wire mesh was jammed between and over the bricks. It covered, barely, a small gap where the bricks converged. Hadidian followed my gaze and offered his assessment.

“I think that is intended to prevent someone’s access.”

A pause, and then, as though answering his own question, he continued: “Yeah, it’s probably a rodent barrier. Not a great one. Kind of stuffed in there.”

It was not a rat, but a past rat! Very likely, the presence of a surfeit of rats prompted this makeshift protection. The handiwork was, indeed, not impressive. We paused to examine it. The mesh was spiderwebbed across the wall—another piece was right below it, another was a yard to the right. Though there was no sign of the animals it aimed to prevent access to, if anything, these
protuberances from the wall seemed likely to
draw
a rat’s attention to the site.
Hmm,
the passing rat might wonder.
Where to enter this fine-looking den site of a wall?
. . .
Aha! At the great mesh gates!

I remembered seeing Hadidian sigh, two blocks before, as we passed a trash can on the sidewalk. Not an unusual trash can—in fact, a rather tidy one, as resident trash cans go here—its lid was just ajar over the yawning can. An “insecure” trash can, he had called it. Almost guaranteed to be visited by the local raccoons that night.

Sure enough, on further examination we saw recently chewed bits of paper peeking out through the mesh on the wall. This was certainly the work of rats, whose ever-growing teeth leave them yearning to gnaw, chew, and pulp whatever they can get their mouths around.

It appeared that we had stumbled across one of the ways to find wildlife—or the traces of wildlife—in the city: look for the traps, barriers, or other munitions set up to deter them or ward them off. As Hadidian and I continued down the street, our attention was drawn upward by a rustling sound. On a flagpole, someone had tied strips of plastic, which whirled spastically in the breeze. Nearby windowsills and protruding ledges were lined with unfriendly spikes to deter animals’ loitering—“loafing,” as it is called by animal experts. While intended to discourage loafers, the plastic strips seem to attract them: as we watched, three pigeons,
Columbia livia,
landed nearby and made themselves comfortable. Pigeons can often be found at just those places that feature pigeon-scaring tactics. A plastic owl peered out placidly from a fire escape. While conceptually this seems like it would dissuade loafing pigeons—they are potentially prey to the predator owl—pigeons easily learn that an immobile, silent, odorless owl is not to be feared. And, indeed, the owl may be a sign of the location of a nice, stable ledge, with access to the crumb leavings of a nearby
resident human. As Hadidian put it, the owl effigies “provide pigeons with something nice to sit on.”

Similarly, the positioning of rodent boxes—large, enclosed traps baited with poison and, with their rat-sized openings, intended to lure rats—is itself a bit of urban ethology. The superintendents or residents who put them out presumably place them where they have seen rats in the past, so the location of these boxes forms an unlikely map of the paths of the city rat. On one block, I noticed that the view behind an apartment building extended all the way to the next street south: somewhat rare in New York, a city without alleys. I pointed this out to Hadidian, who said, simply, “Corridor. That’s a great animal corridor.” That is, it was a potential access route for animals, who would like to travel but prefer to avoid the traffic of the sidewalks and streets. At basement level we saw a string of rodent boxes lined up along the back walls of the buildings open to this ersatz alleyway. This was a rat superhighway.

The boxes spoke not just to the rats’ route, but also to their idiosyncrasies. All the boxes were lined up against the building walls because rats are
thigmotaxic
: a splendid word to describe an animal who likes to walk along walls, touching something as it goes. Thigmotaxic, or thigmo
philic
—touch-loving—animals scurry along at the edges of the spaces we make. They feel most comfortable keeping in contact with something as they travel. You might spot the smudges of their body oil left as they hug the walls while moving. Mice are thigmotaxic; so are cockroaches. It is the same phenomenon, worn slightly differently, that causes caterpillars to move in massive processions, one touching (or clambering over) the caterpillar to his fore, who himself touches the caterpillar in front of him, and so on and so on.

This fact, in turn, tells us something about the biology of the animal. Thigmotaxic animals are probably ones who use the presence
of a wall to orient themselves or navigate. Their sensory systems are often acute, but proximity to a wall limits the territory they must scan for possible dangers. And it makes use of one of their abilities: for rats, it is their ability to pick up low-frequency sounds—essentially, vibrations—with their vibrissae, or whiskers. These modest, twitching face hairs are actually the rat’s best means of discovering what is out there, how far it is, how fast it is moving, and how high it is. More sensitive than human fingertips, whiskers can gauge, say, the size of an opening a rat is ducking into. If their whiskers are damaged, the animals are truly disabled. Researchers have experimentally cut lab rats’ whiskers and found these animals to be not just slower to learn how to navigate through mazes but also likely to drown outright if placed in water.

We humans try
not
to touch things on the street, in public, but whiskers want to touch—to get information about the world through contact. So if you are looking for a whiskered animal, you need to envision the places that allow for lots of touching. Squeezed-into spaces. Too-small holes. Leafy areas. Chewed-out corridors. Pipes, gutters. Curbs.