8.

LOCATIONS

Oppressive Environments

When Japanese troops departed Hong Kong at the end of World War II, they left behind a crumbling fort that covered an area the size of six football fields. Refugees invaded the structure and lived in hundreds of makeshift dwellings until the government built water pipes and tall concrete apartment blocks in the 1960s. The area, known as Kowloon Walled City, became an emblem for the plague of overpopulation. Many of the city’s apartments were barely larger than an office desk, its alleyways were rarely more than a few feet wide, and most of the city was shrouded in perpetual darkness. Doctors and dentists established illegal practices, and Triad gangs opened brothels, gambling houses, and opium dens. By 1987, the tiny city’s population climbed to more than 33,000 residents, making its population seventy-five times denser than the population of Monaco, the world’s most densely populated country. At the same density, the diminutive U.S. state of Delaware could house Earth’s entire human population.

In the mid-1960s, not long after Kowloon Walled City’s population skyrocketed, two researchers at a hospital in Oxford, England, subjected young patients to a controversial experiment on overcrowding. The researchers combed the hospital wards and found fifteen children between three and eight years old, whom they categorized as autistic, severely brain-damaged, or normal. Each day, the children would assemble for “free play” in a room that was designed to hold small groups. Sometimes the experimenters ensured that no more than six children played at once—a comfortable number given the size of the room. At other times the room held more than a dozen children simultaneously. While the children played for fifteen-minute periods, nurses and researchers looked on and recorded their behavior. As expected, the autistic children rarely interacted with their playmates—but they also spent far more time nervously hugging the room’s periphery when it was overpopulated. When joined by only three or four playmates, they spent an average of three minutes on the room’s outskirts, but that number jumped to eight minutes when the room held more than a dozen children. The normal and brain-damaged children didn’t fare much better in the densely populated room. They played happily for ten minutes in smaller groups, but only for five or six minutes when the room was overcrowded. Meanwhile, they spent little more than thirty seconds fighting and snatching toys when the room was sparsely populated, but up to four minutes bickering when the space was congested. Two of the children even had to be restrained from biting their playmates. After only minutes in an overcrowded room, the gregarious children became hostile, and the anxious children were doubly withdrawn.

The Oxford hospital study was groundbreaking, but it left open a number of important questions. Were the results merely a product of the study’s subjects—a small group of children hampered by temporary or ongoing psychological trauma? Or would the results also apply to a larger group of healthy, high-functioning adults? To answer those questions, a large group of psychologists and architects conducted two experiments among eight thousand college students at three institutions in Massachusetts and Pennsylvania. Some of the students lived in high-density towers, some in medium-density apartment blocks, and others in lower-density dorms. The researchers used two subtle techniques to measure whether the students had formed strong social bonds with their neighbors. They began by scattering a series of stamped and addressed envelopes inside the buildings, creating the sense that the letters had been lost on the way to the mailbox. They made sure that the letters were dropped in prominent places so the students couldn’t miss them. Some of the students saw the letters, assumed they were lost by fellow residents, and kindly posted them—a small gesture suggesting a measure of social kinship. When the researchers returned four hours later, they found that 100 percent of the letters in the low-density housing were posted, 87 percent were posted in the medium-density blocks, and only 63 percent were posted in the high-density towers.

In a different set of apartment blocks that similarly varied in density, the researchers placed boxes asking residents to donate used milk cartons for an art project. Calculating the number of cartons that were used by the residents in the blocks, they found again that high-density dwellers were less helpful. Those in low- and medium-density housing contributed 55 percent of their cartons, whereas the students in high-density housing gave only 37 percent of their cartons. These results suggest that high-density living hampers generosity, and other researchers have shown that overcrowding similarly provokes mental illness, drug addiction, alcoholism, family disorganization, and a generally diminished quality of life.

Extreme overcrowding is also associated with claustrophobia: the fear of closed or very densely populated spaces. In contrast to some other human phobias that people acquire with experience—like triskaidekaphobia (fear of the number 13) and agyrophobia (fear of crossing the street)—claustrophobia appears to be innate. Humans today are just as afraid of small, dark rooms as were their ancestors who stumbled into small, dark caves thousands of years ago. We’re driven to preserve a measure of personal space, which is why people respond strongly to brief unintended physical contact. In one study, marketing expert Paco Underhill surreptitiously filmed shoppers as they browsed the aisles of a large department store. Some of the aisles were especially narrow, and the shoppers who stopped to browse in narrower aisles tended to be jostled by other customers who struggled to squeeze past them. Seconds later, the disturbed customers stopped browsing and often left the store altogether. When Underhill later questioned some of the shoppers, they had no idea they had been persuaded to leave the store because they were jostled—but the results were unambiguous and the prescription clear: customers are more likely to remain in stores if the aisles are wide enough to prevent even light collisions, or butt brushes, as Underhill called them.

Overcrowding also creates noise, and researchers have found that the constant hum of everyday life stifles creativity and learning. In the early 1970s, psychologists visited four 32-story apartment blocks in upper Manhattan. The apartments faced onto Interstate 95, one of the busiest highways on the East Coast. Among the apartments’ residents were seventy-three elementary school children who were subjected to the constant rumble of highway traffic—a sound that reached up to 84 decibels. Some scales define 84 decibels as “very loud,” its volume matching the noise from a truck without a muffler, or a loud factory. Prolonged exposure to a noise of that intensity sometimes produces hearing loss, and the noise was formidable even inside the apartments. The children on the towers’ lower floors experienced a racket ten times more intense than the relatively muffled sound that reached the children who lived on the top floors. Consequently, when the researchers administered a hearing test, children who had been living on a low floor for at least four years struggled to discriminate between words that sound similar but have very different meanings. For example, the word pairs gear and beer, or cope and coke, are difficult to distinguish when whispered or stifled by background noise. The researchers reasoned that children with poorer hearing are also less likely to engage in conversation and more likely to experience intellectual difficulties. And that’s what they found: the children who had lived on the lower floors for many years also struggled to read relative to other children of their age. Most distressing, when the children had lived in the buildings for more than six years, the researchers could predict their reading scores with astonishing accuracy by asking just one question: “On which floor do you live?” Since the effect of the noise grew over time, the researchers were able to rule out the possibility that residents on the higher floors were generally smarter, wealthier, or more dedicated to educating their children. Exposing children to cluttered noise for an extended period of time—even the background noise that comes with urban living—is enough to hamper their intellectual development.

Overcrowding and noise pollution are relatively recent problems that barely existed a few hundred years ago, before the Industrial Revolution heralded the arrival of generators and engines. Suddenly, large cities replaced scattered towns and hamlets, and the machines that built those cities were themselves noisy. As so often happens, the best solutions to these modern problems re-create the world as it was before they existed. For one researcher, that solution became apparent when he noticed that hospital patients just a few rooms apart were recovering at very different rates.

The Natural Environment as Panacea

Paoli, Pennsylvania, is a small town not too far from Philadelphia, with a local suburban hospital. Patients at Paoli Memorial Hospital recover in a row of rooms facing a small courtyard. In the early 1980s, a researcher visited the hospital and gathered information about patients who had undergone gallbladder surgery between 1972 and 1981. Gallbladder surgery is routine and generally uncomplicated, but most patients in the 1970s were kept for a week or two before they returned home. Some took longer to recover than others, and the researcher wondered whether subtle differences between the hospital rooms might explain this discrepancy. Some of the rooms on one side of the hospital faced onto a brick wall, whereas others slightly farther down the corridor faced onto a small stand of deciduous trees. Apart from their differing views, the rooms were identical.

When the researcher looked at their recovery charts, he was struck by how much better the patients fared when their rooms looked out onto the trees rather than the brick wall. On average, those who faced the brick wall needed an extra day to recover before returning home. They were also far more depressed and experienced more pain. On average, their nurses recorded four negative notes per patient—comments like “needs much encouragement” and “upset and crying”—whereas those with a view of the trees warranted negative notes only once during their stay. Meanwhile, very few of the patients who looked out onto the trees required more than a single dose of strong painkillers during the middle part of their stay, whereas those facing the wall required two or even three doses. Apart from their view, the patients had received identical treatment at the hospital and were otherwise very similar. Each patient with a view of the trees was matched with a patient whose room looked out onto the brick wall, so that their age, gender, weight, status as smokers or nonsmokers, and attending doctors and nurses were controlled as tightly as possible. Since those factors were controlled, the only explanation was that patients who looked out at a stand of trees recovered more quickly because they were lucky enough to occupy rooms with a natural view.

These results are surprising because the effects are so large—much larger than the effects of many other targeted treatment interventions. By some measures, patients who gazed out at a natural scene were four times better off than those who faced a wall. Strong results usually inspire skepticism, but plenty of studies have shown similar effects. In one of those studies, two environmental psychologists approached 337 sets of parents who lived with their children in five rural communities in upstate New York. The researcher scored the “naturalness” of each family’s home, awarding points for natural views, indoor plants, and grass-covered yards. Some of the children had experienced little stress growing up, rarely fighting or getting punished at school, but others were bullied and struggled to get along with their parents. When the researchers measured the happiness and well-being of the students in their study, they noticed that those who had experienced hardship were distressed and lacking in self-esteem—except when they lived in more natural environments. The presence of nature seemed to buffer them against the stresses that hampered other children who lived in predominantly man-made environments.

In an even more direct test, another group of researchers asked a hundred sets of parents with children who suffered from attention deficit disorder (ADD) how their children responded to different playtime activities. Children who have ADD are often restless and distracted. But the parents reported that green activities—like fishing and soccer—left their children in a far more relaxed, focused state. It wasn’t that the children who spent time outside were merely happier, more likely to interact with friends, or more active—in fact, those who sat indoors, in a room with natural views, were calmer than children who played outside in man-made environments that were devoid of grass and trees.

What is it that sets natural environments apart from others? Why shouldn’t a quiet streetscape have the same effect as a quiet natural landscape, for example? Architecture has its own beauty, and some people prefer urban environments to natural environments, so why does nature seem to have such powerful restorative effects? The answer is that natural environments have a unique constellation of features that set them apart from man-made locations. Just before the dawn of the twentieth century, William James, one of the early giants of modern psychology, explained that human attention comes in two different forms. The first is directed attention, which enables us to focus on demanding tasks like driving and writing. Reading a book also requires directed attention, and you’ll notice that you start to zone out when you’re tired, or you’ve been reading for hours at a time. The second form is involuntary attention, which comes easily and doesn’t require any mental effort at all. As James explained, “Strange things, moving things, wild animals, bright things, pretty things, words, blows, blood, etc., etc., etc.” all attract our attention involuntarily. Nature restores your mental functioning in the same way that food and water restore your body. The business of everyday life—dodging traffic, slavishly making decisions and judgment calls, interacting with strangers—is depleting, and what man-made environments take away from us, nature gives back. There’s something mystical and, you might say, unscientific about this claim, but its heart actually rests in what psychologists call attention restoration theory, or ART. According to ART, urban environments are draining because they force us to direct our attention to specific tasks (e.g., avoiding the onslaught of traffic) and grab our attention dynamically, compelling us to “look here!” before telling us instead to “look over there!” These demands are draining—and they’re also absent in natural environments. Forests, streams, rivers, lakes, and oceans demand very little from us, though they’re still engaging, ever changing, and attention-grabbing. The difference between natural and urban landscapes is how they command our attention. While man-made landscapes bombard us with stimulation, their natural counterparts give us the chance to think as much or as little as we’d like, and the opportunity to replenish exhausted mental resources.

In the early 2000s, more than a hundred unlucky Dutch students were subjected to an experiment that revealed nature’s capacity for mental restoration. The students entered a lab and sat in front of a screen that began to play scenes from the controversial film Faces of Death. First, a woman decapitated a rooster; then sheep and bulls were slaughtered in an abattoir. Two vegetarians, repulsed by the images, left the room and refused to return, while the remaining students stared at the screen transfixed and horrified. As the video ended and the students caught their breath, the researcher began a second video. Mercifully, the second video was less distressing, depicting the scenes a person might view during a seven-minute stroll. For some of the students, the video passed through a Dutch forest, whereas the other students watched a video that progressed down a street in the Dutch city of Utrecht. After watching the video, the students who imagined walking through the forest scene reported feeling happier, more relaxed, and less angry than those who imagined walking through the cityscape. They were also more alert, which enabled them to perform better on a task that required them to search for specific letters of the alphabet among an array dominated by irrelevant characters. Merely asking students to imagine strolling through a natural scene was enough to dampen the distressing and attention-sapping effects of the Faces of Death video.

Healers in Japan and Germany have long heralded the benefits of natural therapy, recognizing that humankind has spent 99.99 percent of its history living in natural environments. The Japanese version of natural therapy is shinrin-yoku, or forest bathing, which requires that patients walk for extended periods through forested areas while inhaling woodsy scents that complement the sylvan atmosphere. German Kneipp therapy similarly requires that patients perform physical exercises in forest clearings. These alternative therapies aren’t just idle cultural quirks, and researchers have found that patients enjoy a wide range of benefits. Among others, compared with people who walked through urban areas, shinrin-yoku patients had lower blood pressure, lower pulse rates, and lower cortisol levels, a marker of reduced stress. People who are exposed to natural scenes aren’t just happier or more comfortable; the very building blocks of their physiological well-being also respond positively to natural therapy.

Natural environments promote calmness and well-being in part because they expose people to low levels of stress. These stressful experiences are tame in comparison with the trials and tribulations that most of us associate with stress—workplace drama, traffic jams, and wailing children on international plane trips. Humans thrive with some stimulation, but we’re incapable of coping with extreme stressors, which push us from the comfortable realm of eustress (good stress) to the danger zone of distress (bad stress). Interesting locations, including busy natural environments, are so beneficial that physicians have begun to suggest that they might offer a cheap and effective way to lessen the effects of certain cancers.

One team of researchers showed that women who were recently diagnosed with early-stage breast cancer were far more capable of completing challenging mental tasks when they immersed themselves in natural environments for two hours each week for approximately two months. The interventions began when the women were diagnosed, and continued beyond surgery into the recovery period. Like many distressed patients who begin to battle life-threatening illnesses, the women struggled to complete difficult mental tasks shortly after they were diagnosed. Those who spent time in natural environments improved progressively, regaining their capacity to devote attention to demanding mental puzzles. Meanwhile, the patients who were not exposed to the nature-based intervention tended to struggle with similar tasks throughout the test period. Paying better attention is obviously a long way from recovery, but patients with sharper minds often respond better to treatment, stick to their treatment regimens, and behave more proactively during recovery.

Unfortunately, nature occupies an ever-smaller portion of the earth’s surface, and millions of urbanites live miles from forests, lakes, and oceans. Instead, we’re faced with urban clutter in the form of billboards, signs, and other written material, and recent estimates suggest that we process thousands of these written messages each day. Children and teens between the ages of eight and eighteen are especially overloaded, spending almost every minute of leisure time attached to TVs, smartphones, and computers. Research shows that in the absence of natural restoration, the human brain copes with this clutter by going into overdrive, briefly scanning the environment more clearly and deeply than it usually does, until fatigue forces it to return to a stable state of shallower mental processing. As two game-show contestants demonstrated, this capacity to engage additional mental resources is sometimes triggered by subtle cues in the environment.

Disfluency and the Tendency to Think More Deeply

Who Wants to Be a Millionaire is one of the most successful TV game shows in history. It’s also an excellent place to watch people grapple with disfluency—the experience of struggling to make sense of information. The show has more than a hundred international variants, but in each case contestants answer trivia questions that become increasingly difficult as they’re worth larger sums of money. Two of the U.S. show’s most famous contestants are John Carpenter and Ogi Ogas, who both walked away with impressive winnings. On November 19, 1999, Carpenter became the first contestant to win $1 million on the U.S. show. For the million-dollar question the show’s host Regis Philbin asked Carpenter which one of the following presidents appeared on the television show Laugh-In: Lyndon Johnson, Richard Nixon, Jimmy Carter, or Gerald Ford. Carpenter smiled briefly, then asked to phone his parents. In using this “lifeline,” Carpenter implied that he was stumped by the question and sought help by “phoning a friend.” Usually, when contestants phone a friend, they rush to ask the question as quickly as possible within the thirty-second time limit, and hope their chosen friend will be able to help. In this case, Carpenter used a very different tack. When Philbin told him to ask the question, he said:

Hi, Dad . . . I don’t really need your help, I just wanted to let you know that I’m gonna win the million dollars . . . because the U.S. president that appeared on Laugh-In is Richard Nixon. That’s my final answer.

Carpenter was right, and he’d known the answer from the second he saw the question. The smirk that briefly crossed his face was the hallmark of fluent—smooth and effortless—mental processing. A small space in his long-term memory bank housed the link between Richard Nixon and Laugh-In, and the answer appeared to him without demanding much mental effort. For all the ease in Carpenter’s response, Philbin might as well have told him that for a million dollars, he’d need to state his own name aloud or calculate the sum of one and one.

Seven years after Carpenter’s suave exhibition, cognitive neuroscientist Ogi Ogas faced his own million-dollar question. Meredith Vieira, the show’s new host, asked Ogas which one of these ships was not one of the three taken over by colonists during the Boston Tea Party: Eleanor, Dartmouth, Beaver, or William? Ogas agonized, and you could see him frantically searching the long aisles of his memory. Over the course of four agonizing minutes, he narrowed down the options and almost decided to answer “William.” Just before he answered, a more conservative voice chimed in and told him to take the $500,000 he’d already won, rather than risk the prospect of walking away with a comparatively measly $25,000. An aversion to risk had cost him the chance of winning $1 million. Later, Ogas wrote about the experience:

I immediately had an intuition that one of the ships at the Tea Party was Dartmouth. I reflected on Dartmouth, using it as a prime. I repeated the ship’s name aloud and silently to myself. Gradually, the name of another ship formed in my mind, echoing each repetition of Dartmouth: Beaver . . . And then, faintly, like the reflection of the moon on a midnight lake, the name of a third ship dimly waxed upon the murk of my mind: Eleanor . . .

I blinked. Suddenly, I became aware of the wobble of the chair, the murmurs of the audience . . . Intuition? What are you thinking?! You’re risking a house! You can’t possibly know the answer to this arcane question! There’s no such thing as intuition! . . .

”I believe I’ll walk with the money I’ve got. That’s my final answer.”

With the wobble of a chair and the murmurs of the audience—environmental triggers that tempered his confidence—Ogas suddenly realized that $475,000 was too much to risk on a hunch. In the face of environmental disfluency, he paused, reconsidered, and chose to take the more conservative route. The differences between Carpenter’s and Ogas’s experiences show that disfluency often functions as a useful gauge for determining confidence. Carpenter’s response arose fluently, and he was right to be confident, whereas Ogas’s response arose haltingly without the same sense of ease that people generally associate with certainty. In a series of experiments I ran with three other psychologists, I tested whether disfluency might be a useful signal that tells people to commit extra mental resources to a problem. We may be cognitive misers most of the time, thinking as little as possible, but that’s not true all the time. There must be prompts that tell us to think more deeply when the situation demands more effort.

In the world at large, most of the information we process arrives in the form of letters, words, sentences, and paragraphs arranged to form coherent statements. Most of the time those pieces of information are easy to read, because designers have perfected fonts and typefaces that print clearly and legibly. Sometimes, though, for one reason or another, people choose to print written information in fonts that have the same effect as Ogi Ogas’s wobbly chair—they’re difficult to read, so they disrupt the mental reverie that accompanies most of our thinking. While most written words are printed in clear fonts, from to , and to , some are printed in elaborate and condensed alternatives, like and , or and . Advertisers rely on these fonts to distinguish their messages from their competitors’ messages, often written in simple, clear, overused fonts. One classic example is the widely used and eminently readable , which is the font of New York City subway signs and dozens of company logos, including those of Nestlé, American Airlines, Lufthansa, American Apparel, and Jeep. But how do people think differently when the environment features words printed in complex fonts that are far more difficult to read?

My colleagues and I tried to answer that question when we asked students to answer a set of three brainteasers that form a measure of intelligence known as the Cognitive Reflection Test. The questions are devilishly tricky, because they inspire immediate answers that are both wrong and intuitively appealing. Those answers arise fluently, like John Carpenter’s response to the million-dollar question. People with patience eventually notice that the answer is wrong, and with extra mental commitment they’re able to answer with the correct alternative. Here’s one of the questions from the test (the others are printed in this chapter’s notes at the end of the book):

A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?

Most people arrive instinctively at the conclusion that the bat costs $1 and the ball costs 10 cents—which is wrong when you think more carefully. Yes, the two sum to $1.10, but the bat costs only 90 cents more than the ball. The right answer, which anyone with basic arithmetic skills can verify, is that the ball costs 5 cents. Many people answer this question incorrectly precisely because they’re cognitive misers, impatient and ready to move on to the next task that demands mental resources. In the experiment, we wondered whether disfluency might signal to people that the question demanded more mental effort, so half the students answered the questionnaire printed in a fluent font, whereas the other half answered the questionnaire printed in a smaller, gray, italicized text:

A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?

As expected, people answered the three questions correctly more often when they were difficult to read. On average, they correctly answered 2.45 of the three questions correctly, whereas the students who read the questionnaire printed in a clear font averaged only 1.90 correct answers to the three questions. Later, we showed the same effect with complex logic problems, again showing that people answered them correctly more often when they were printed in a disfluent font.

The complex fonts that populate modern environments function like an alarm, signaling that we need to recruit additional mental resources to overcome that sense of difficulty. Just like other alarms, sometimes it proves faulty. Though we need to know when to think more deeply, the same alarm also makes us more conservative, sending a warning that something in the environment is risky or dangerous.

This link between disfluency and riskiness probably explains why cognitive psychologist Danny Oppenheimer and I found that people began submitting increasingly revealing confessions on the website Grouphug.us in August 2008. The website invites people to share anonymous confessions in exchange for hugs from sympathetic readers. Some confessions are very revealing, whereas others are tame and barely warrant anonymity. Before August 2008, the site was formatted quite disfluently, with gray text against a similarly dark black background:

Then in August 2008 the site’s creator had a change of heart. He decided to make the text darker and the background lighter—the standard black text on white background format:

Now the text on the site was far easier to read, and people who considered submitting their own confessions were greeted with a fluent mental experience. When Danny Oppenheimer and I combed the site for confessions, we found that the confessions were more revealing after the site’s creator adopted the new, fluent format. In other studies, we found that people were more willing to disclose revealing personal flaws when prompted by a request that was printed in a clear font, rather than a light gray font on a white background.

The same mental alarms that prevent people from revealing personal information also signal the presence of immorality. Imagine, for example, that you’re told the following tale about a questionable culinary decision:

A family’s dog was killed by a car in front of their house. They had heard that dog meat was delicious, so they cut up the dog’s body and cooked it and ate it for dinner.

The family wasn’t hurting anyone (or anything—the dog was already dead), but most Westerners would consider eating a dead pet dog morally questionable. If I asked you to rate the family’s behavior on a scale that ranged from zero to ten, where zero indicates not morally wrong at all and ten indicates very morally wrong, what rating would you assign? What about a case where a brother and sister kiss passionately on the lips? How wrong is that behavior? Again, assuming the kiss is consensual and it doesn’t harm anyone, it’s difficult to find moral fault with the act except to say that it doesn’t feel right, or offends some higher notion of religious or transcendent propriety. When fellow psychologists Simon Laham, Geoff Goodwin, and I asked people to rate the moral wrongness of these acts, we also introduced a fluency manipulation. For some of the raters, the acts were described in writing against a speckled gray background, whereas for others the text was much easier to read. Here’s another example in similar formats:

Moral transgression printed in disfluent format.

Moral transgression printed in fluent format.

People generally found the violations quite offensive, rating them around 9 out of 10 on the moral wrongness scale—but these ratings dropped to 7.5 when the violations were printed fluently after earlier violations had been printed disfluently. When the later violations were surprisingly easy to read, the raters interpreted that experience to imply that the violations were less morally offensive.

The written words that fill modern urban environments shape how deeply we think, and whether we’re more likely to open up to other people or judge them for behaving immorally. Just as disfluent experiences direct us to think more deeply, other cues in the environment tell us how to behave in novel situations. Like chameleons we blend into the background, unconsciously adopting the behaviors that strike a balance between appropriate and rewarding.

Mental Chameleons

Artificial illumination is a modern miracle, blurring a line that separated night and day for millions of years before mankind found a way to reliably turn darkness into light. Today lighting is taken for granted to such an extent that we barely notice the light fixtures as we enter a room for the first time. It takes some effort and attention to direct your gaze toward the ceiling, to determine whether the lightbulb is incandescent, halogen, or fluorescent, and to decide whether you might be more comfortable if the resulting glow were slightly brighter or dimmer. Though we’re apt to overlook a room’s brightness, U.S. Supreme Court justice Louis Brandeis was onto something when he said, “Sunlight is said to be the best of disinfectants.”

In a recent paper, three psychologists tested the truth of Brandeis’s statement. Students at the University of North Carolina participated in an experiment that gave them the opportunity to earn up to $10. The students had five minutes to complete as many of twenty math problems as they could. For each problem, they searched for three numbers from an array of twelve that summed to ten. The problems were time-consuming and took plenty of mental effort. Following is a sample question to give you a sense of the students’ task—and keep in mind that they had only five minutes to complete twenty similar problems.

Three of these numbers sum to ten. The solution is in this chapter’s notes, at the end of the book.

Each of the students completed the experiment in the same small room, but the room was brightly lit with twelve lightbulbs for some of them, and more dimly lit with only four bulbs for others. The dimly lit room was still bright enough to allow the students to complete the task without difficulty, but it was noticeably darker than most rooms in an average university building. After five minutes had elapsed, the students told the experimenter how many problems they had answered correctly, and collected 50 cents for each completed problem. The students struggled regardless of the room’s illumination, completing about seven problems during the five-minute period—but their claims varied greatly depending on the room’s brightness. Students in the bright room were reasonably honest, reporting that they completed between seven and eight problems. Meanwhile, those in the dimly lit room inflated their scores by roughly 50 percent, claiming an average of more than eleven completed problems! Somehow, the students in the dimly lit room were liberated from the moral constraints of behaving honestly, a result that the authors attributed to the illusion that the darkness preserved their anonymity.

A room’s lighting remains largely unchanged as time passes, but locations change as they come to reflect the people who inhabit them. Some of that social residue inspires good behavior, but some pegs the location as a hotbed of immorality and crime. For example, the heavily debated broken windows theory suggests that would-be offenders are encouraged to commit crimes in neighborhoods with broken windows, which suggest that the area’s residents don’t care enough to maintain their property. The theory’s authors, James Wilson and George Kelling, gave two examples to illustrate the theory:

Consider a building with a few broken windows. If the windows are not repaired, the tendency is for vandals to break a few more windows. Eventually, they may even break into the building, and if it’s unoccupied, perhaps become squatters or light fires inside. Or consider a sidewalk. Some litter accumulates. Soon, more litter accumulates. Eventually, people even start leaving bags of trash from take-out restaurants there or breaking into cars.

Since 1982, when Wilson and Kelling proposed their theory, the second littering example has received plenty of experimental support. In one study, social psychologists placed flyers on 139 cars in a large hospital parking lot. They were curious about whether the cars’ drivers would throw the flyers in the trash, or whether they would instead litter by leaving them in the parking lot. Before some of the cars’ drivers emerged from the parking lot elevator, the researchers scattered discarded flyers, candy wrappers, and coffee cups throughout the parking lot. At other times, they removed every last cigarette butt and piece of trash from the parking lot floor, conveying the idea that littering was both unusual and inappropriate. Nearly half of all drivers littered when the parking lot was already covered in litter—what’s one more piece of trash atop a foundation of garbage?—but only one in ten drivers littered when the parking lot was spotless. The researchers added another twist, asking a stooge to conspicuously drop an unwanted flyer on the ground just as some of the drivers were exiting the elevator. This act drew the drivers’ attention to the existing state of the parking lot, either emphasizing that it was already full of litter, or highlighting how neat it was before the stooge callously cast aside his discarded flyer. When the stooge drew the drivers’ attention to the state of the parking lot, only 6 percent littered in the clean parking lot, whereas a dramatically higher 54 percent littered in the already cluttered parking lot. The drivers adopted the behavior that seemed most appropriate given their understanding of the area’s prevailing norms.

Even subtler cues that you might expect to fade into the background shape how we think about the world. In a series of studies, social psychologist Virginia Kwan and I asked a researcher to approach people in various parts of New York City. All of them were Caucasian Americans, but some were walking through Chinatown, while others were walking through Manhattan’s Financial District and Upper East Side. The researcher asked them to complete a few brief questions, some that asked them to predict how financial stocks would perform in the coming six months, and others that asked them to predict weather conditions following a string of sunny or rainy days. As I mentioned in chapter 6, on culture, American and Chinese people have very different ideas about how the world changes. Americans are often surprised by change, expecting financial stocks that have performed well in the past to continue to do well in the future, and similarly expecting weather conditions to remain relatively consistent. In contrast, many Chinese people subscribe to the Taoist I Ching principles, which suggest that change is inevitable; financial stocks and weather conditions that seem favorable today are likely to take a turn for the worse tomorrow, but a downturn in the stock market and rainy weather today are likely to precede a burst of stock appreciation and sunny weather tomorrow.

As you might expect, then, the Americans in the Financial District and Upper East Side completed the questionnaires like typical Americans: they preferred to invest in stocks that appreciated, and expected weather patterns to continue unabated. But the Americans passing through Chinatown, who were otherwise indistinguishable from those in the more typical American neighborhoods, perceived the world very differently. For that brief moment, they thought more like Chinese people than like Americans. They expected the appreciating stocks to depreciate over the coming six months, and they expected sunny days to be replaced by rain, and rainy days to be replaced by sun. These effects were strongest, as you might expect, among the Americans who were aware of the Chinese belief in change embodied in the I Ching. Merely responding in a location filled with Chinese paraphernalia led those people to adopt Chinese cultural norms.

We found the same patterns of results when a research assistant approached people outside a Chinese supermarket in New Jersey. Some of them were entering the market—not yet exposed to the plethora of Chinese sights and sounds—while others were leaving after finishing their shopping trip, already bombarded by reminders of Chinese culture. Those who were leaving the supermarket adopted a mind-set associated with Chinese cultural beliefs, expecting appreciating stocks to depreciate imminently and investing $300 less of a fictional $1,000 sum in those stocks, whereas those who were yet to enter the market tended to think like typical Americans, investing almost the entire sum in appreciating stocks.

These studies tell us something profound and perhaps a bit disturbing about what makes us who we are: there isn’t a single version of “you.” When you’re surrounded by litter, you’re more likely to be a litterbug; when you’re walking past buildings with broken windows, you’re more likely to disrespect the property that surrounds you. These norms change from minute to minute, as quickly as a New Yorker walks from one part of the city to another. It’s comforting to believe that there’s an essential version of each of us, that good people are good, bad people are bad, and that those tendencies reside within us rather than in the sights, sounds, and symbols that populate the landscapes that surround us from moment to moment. But social psychology calls that belief into question. In fact, even our memories—the building blocks that construct the evolving story of who we are across time—are tagged with the locations where they were formed. Emotionally jarring memories adhere to this tag with particular determination, which explains why people remember where they were when they learned of JFK’s assassination, the death of Princess Diana, and the string of tragedies on September 11, 2001. These memories aren’t always perfectly accurate, but as their name suggests, so-called flashbulb memories are vivid snapshots of a moment and place in time when we learn an emotional and personally relevant piece of news. These tags, which bind events to the places where they occurred, explained a strange anomaly forty years ago, when thousands of Vietnam War veterans returned to the United States with a potentially calamitous drug addiction.

Context Reinstatement

During the Vietnam War, a combination of boredom and anxiety pushed many enlisted soldiers to try heroin and opium. In 1970, at the height of the epidemic, 40 percent of all enlisted men had tried at least one of the two drugs. When the U.S. government discovered that soldiers had been using heroin, they feared that the war’s end would herald a public health crisis. Heroin relapse rates are as high as 90 percent in the short term, so the government had good reason to worry. The men returned from the war with many problems, but to the surprise of many drug experts, very few of them relapsed. Psychologists and doctors continue to debate the issue today, but most agree that the critical difference between most heroin users and the soldiers who used heroin in Vietnam was that the soldiers were forced to leave the location in which they had used the drug. Unlike most recovering addicts, who find themselves in locations that reinstate the drug-using context, few Vietnam vets found themselves in the tropical jungle setting that colored their original exposure to the drug.

Part of the reason why context reinstatement—returning to an emotionally charged location—plagues heroin users is that the location forces them to relive old, related memories. Wise teachers turn this fact on its head by telling students to study for exams in a situation that mirrors the exam context as closely as possible. Their advice draws on a classic psychology experiment that showed that locations form a lens through which we perceive newly acquired information. The researchers asked eighteen scuba divers from a university diving club to memorize lists of words. Sometimes the divers memorized the lists underwater, and sometimes they memorized them onshore. Randomly selected words would be just as easy to remember on land as underwater if they weren’t somehow associated with the location where they were first encountered. But the scholars found that the divers who memorized the words underwater recalled them much more accurately when they were again immersed in the water, whereas the divers who memorized the words on land recalled them with greater accuracy when they were again perched on dry land. The divers who learned the lists underwater perceived them through a watery mental lens, and that location-based tag was activated when they were again immersed in the water, pushing those words to rise more rapidly to the surface of their minds. Similar studies have shown that studying while drunk is beneficial only if you’re also drunk during the exam. In a famous example that later inspired the scuba diving study, seventeenth-century philosopher John Locke told the story of a man who learned to dance in a room containing an old trunk, and couldn’t dance thereafter unless he shared the room with the same trunk.

Locations vary along countless dimensions, each playing a distinct role in shaping our thoughts, feelings, and behaviors. At the one end of the spectrum, Locke’s man was fixated on the narrowest of cues—a particular trunk—but at the other end some environmental cues are considerable in scope. Perhaps the grandest of all cues in the world around us are the weather conditions that define every moment we spend outdoors. Each time you leave the sheltered indoors, you subject yourself to the whims of the seasons. As the New York Mets discovered during one baseball game in 2009, it’s much harder to remain coolheaded when a hot day compounds the heat of competition.