by Sian Beilock
Here is the basic design of the Milgram experiments: People were offered $4.50 to be part of an experiment on “human memory”—$4.00 for the experiment and 50 cents for carfare ($4.00 was a pretty good wage for an hour’s worth of work in the 1960s, especially if you were a starving college student, and 50 cents more than covered round-trip bus fare). When the volunteers arrived at Milgram’s lab, they met the experimenter, a stern man who introduced himself as Mr. Williams and was dressed in a gray lab coat. Mr. Williams introduced the participant to another person who appeared to be volunteering for the same study but was actually an actor hired to play the part. Then Mr. Williams announced that one of the volunteers was going to play the role of the teacher and the other was going to be the learner. To determine who was going to assume which role, both drew a slip of paper from a bowl. The slips were rigged: they all said “teacher.” The second volunteer pretended that he had drawn the learner role.
“Teacher” and “learner” were put in different rooms connected by an intercom system, and the teacher was given a list of word pairs the learner was to memorize. The teacher was instructed to read the list over the intercom, then, starting at the beginning, to reread the first word in the pair. The learner was to respond by picking the word that satisfied the pair. Every time the learner got a word wrong, the teacher was to give the learner an electric shock, increasing the voltage with each wrong answer. So that the teacher knew what the shock felt like, the experimenter shocked the teacher before the experiment began. The teacher really believed that he was administering a shock to the learner. Indeed a tape recorder yoked to the shock machine played prerecorded cries of agony when the teacher administered a shock for a wrong answer.
Milgram polled some Yale students (who didn’t take part in his experiment) and psychiatrists beforehand to find out how many people they thought would actually follow the experimenter’s instructions to shock a stranger. Both students and psychiatrists thought very few people (maybe 1 percent) would do so, but Milgram found that 65 percent of the volunteers, twenty-six out of forty, continued shocking until they had given the maximum 450-volt shock three times. A standard U.S. socket maxes out at 120 volts, so 450 volts hurts a lot.
Both men and women shocked the learner at the same rate, and compliance was also strikingly similar whether Milgram conducted his experiment with Yale students or a broader sample of the general population. One factor that did affect how likely someone was to give a stranger a shock, however, was the physical distance between the two people. The teacher was less likely to shock the learner if the learner was physically closer, in the same room rather than a separate room. Being physically close seemed to relay a sort of mental closeness that minimized the suffering the teachers were willing to inflict.15
Why does physical distance alter our willingness to impose harm on someone? We understand others, and relate to others, in part by how close we are to them physically. Physical distance information is actually built into the design of the human brain. The computation of information about how close we are to a looming threat shifts from the frontal cortex to more rudimentary, pain-related regions toward the middle of the brain as we get nearer to a possible danger.16 When we are in close physical proximity to someone or something, our brain’s more primitive emotional regions perk up, which could help us better understand what others are feeling. A close physical distance paves the way for a strong emotional connection, while greater distance capitalizes on the association we have between distance and disconnection.
The effects of physical distance on feelings of psychological closeness offer an important lesson for our interactions in the virtual world. These days, in-person meetings are regularly traded for video conferencing, whether to pitch to clients, strategize among board members, or even interview for a job. Although virtual interactions have some advantages, limiting the cost and time of travel, they may have downsides. Our mind cannot be separated from our body, and, though we may wish otherwise, research shows that physical distance encourages the perception of being psychologically distant. In short, if you want to see eye to eye with someone, there may be value in being in the same room with him. If we use information about physical distance to render judgments about psychological distance, it may be harder to get on the same page with others in a negotiation, to trust them, and to come to a mutually beneficial outcome in the end. If you are a job candidate and have the choice of an in-person interview or one over a virtual connection, you will likely benefit from choosing the former. Our physical environment activates feelings of closeness or remoteness without our even knowing it.
Our body shapes our attachment to others. Just as loneliness is partly built on physical coldness and social pain on our physical pain system, moral transgressions can also stem from the physical nature of disgust. There is something to the saying “He who has clean hands and a pure heart may ascend the hill of the Lord.” There are parallels between physical and moral contaminants.17
Cleansing the Body
What do Lady Macbeth, religions throughout history, and parents who wash their kids’ mouths out with soap have in common? They all believe in a link between physical and moral cleanliness. Both the Christian ritual of baptism and the Jewish ritual of the mikva involve metaphorical and physical baths. “Arise and be baptized, and wash away your sins,” the Bible says. The link between physical and moral cleanliness is reflected in Islamic traditions too. Many washing rituals are believed to help root out psychological demons. In Shakespeare’s tragedy Lady Macbeth attempts to cleanse her conscience of her culpability in the murder of King Duncan by washing her hands repeatedly.
People often think about morality in terms of cleanliness. That’s why, when we recall an immoral past behavior like cheating on a test or lying to someone, we often have an urge to physically clean ourselves. The physical act of cleaning helps us feel psychologically cleaner. It also tends to be specific. When volunteers in a role-playing game were asked to communicate a mean lie via voicemail or email, they were more likely afterward to prefer products that would help clean the body part they used to do the dirty deed. People who had left the nasty voicemail preferred the mouthwash over the hand sanitizer; those who had sent the nasty email showed the opposite preference.
When we soil our hands, we wash them; when we drink sour milk, we wash out our mouths. This specificity of cleaning is quite functional; it gets rid of the adverse substance, reducing the risk of contamination or disease. The fact that this exactness spills over into our psychological state is a prime example of how the regulation of moral behavior may be built on procedures of physical cleansing and disease reduction. It’s good evidence for a reuse of the same neural circuits that helped us stay disease-free. We have evolved to tack on new functions to existing behaviors already in place. In this way, our ability to reason about abstract ideas, from love to morality, is driven by our concrete experiences acting in the world.
Cleansing acts actually make us feel better about ourselves and help restore moral cleanliness. That shower that people take after they have cheated on a spouse may do a lot more good than simply getting rid of the physical evidence; it also helps rid them of a guilty conscience. People routinely deal with guilt and other negative feelings after committing bad deeds by physical cleansing. Sometimes it is as simple as washing one’s hands of the situation.18
In the biblical story of the trial of Jesus, he was arrested and brought to the governor of the province, Pontius Pilate, who was reluctant to sentence him to death. Pilate publicly washed his hands, telling the crowd that he would not take the blame for Jesus’ death and was washing his hands of Jesus’ blood.
The body embodies abstractions physically. An ethical violation is a soiling of your character. To feel better, clean your body. If you already feel physically clean, but you have witnessed someone else doing something immoral, you may make harsher moral judgments on issues ranging from abortion to drug use. Dov Cohen, a psychologist at the University of Illinois
, has been studying this correlation between the physical and the moral for the past several years.19 One question Cohen asks is how universal the link is between physical and moral disgust. He has capitalized on some interesting differences between cultures as a way to answer that question. There are some real differences in how religions think about moral transgressions. For Muslims and Protestants, just having bad thoughts is considered impure. But for Hindus and Jews, it’s the actions that matter; you can think all the negative or immoral thoughts you want as long as you don’t act on them.
By comparing how people with different religious backgrounds rated how morally wrong certain thoughts and behaviors were, Cohen was able to document the power of cleanliness. He discovered that, when people rubbed their hands together as if they were washing them, they made more severe moral judgments of others than when they weren’t mimicking washing movements. The exercise was presented to volunteers as a way to warm up their hands for a video game they were going to play; they were not conscious of making washing movements. Most striking, Cohen discovered that the hand-washing movements produced greater condemnation for immoral beliefs among Muslims and to a lesser degree Protestants, but for Hindus and Jews, only the disgusting behaviors were judged morally wrong. Even though the link between physical and psychological cleanliness seems to be universal, what counts as impure varies across cultures.
When we do something bad, washing ourselves makes us feel better. But when we bring our own feelings of disgust to bear in making moral judgments about others, being clean makes us harsher about other people’s “dirty” behaviors—and for some religions, other people’s dirty beliefs too.
The fusing of mental and physical cleanliness isn’t limited to moral transgressions or bad deeds done. As echoed in a line in one of Oscar Hammerstein’s most famous songs, “Gonna wash that man right outta my hair,” we believe that we can wash away our sins (or at least our bad feelings about a situation or relationship). Yet we also believe it’s possible to wash away the good, specifically good luck, as if washing our hands is akin to “wiping the slate clean.” It’s not uncommon for an athlete to go an entire season without washing an armband or a pair of socks when they are on a winning streak because they fear physical cleansing will get rid of their psychological advantage.
It may not be particularly surprising that how much people are willing to bet when they gamble is linked to whether they have previously been on a winning or a losing streak. But it’s also the case that people’s wagers depend on whether they have just washed their hands. When gamblers don’t wash, they bet more money on the next round if they were on a winning streak than if they were on a losing streak. Among those who did wash, having a winning or losing streak had no impact on how much they gambled. People are driven by the idea—at least on an unconscious level—that washing can remove the influence of their past gambling streak (whether good or bad). So when people wash, the gambling outcomes of the past no longer seem to matter.20 When you understand that the brain views physical and mental cleansing as largely interchangeable, all sorts of rituals, behaviors, and decisions that once seemed to have no rhyme or reason make a lot more sense.
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Not only can cleaning our body enhance psychological well-being, moving our body does too. In the next chapter we explore the relation between exercise and sharp thinking. Most books on exercise tout the importance of exercise for physical health. These books, as a whole, though, focus less on the story of how exercise can be used to be sharper mentally.21 Exercise is a tool to increase mental fitness.
CHAPTER 9
Movement
HOW EXERCISE ENHANCES BODY AND MIND
The Running Mind
I wear a Fitbit on my left wrist day and night, while washing dishes and even in the shower. In fact the only time I take it off is when I get an email message warning me the battery is low. And then I remove it reluctantly, preferably before I go to sleep and am not likely to be walking around. Fitbit is a fitness tracker I wear as a wristband that tracks my steps and the minutes throughout the day when I am active. My friend Melissa turned me on to it after she got one as a way to make sure she was keeping active during her pregnancy. We could compete against each other, she said. The one who takes the most steps a day wins. Never one to turn away from a little competition, I jumped at the chance, not only to try to show up my friend but because I was in the middle of teaching a class on neuroscience and education at the University of Chicago and we had just finished reading several new research papers on the power of exercise in changing the brain. If tracking my activity with the Fitbit motivated me to take more steps throughout the day, then why not try it? It seemed like a good idea to practice what I was teaching.
I am a runner and make sure to get in several runs a week, but before I had the Fitbit I never realized how much of a couch potato I was when I wasn’t lacing up my sneakers. The device made me mindful that the little things I did could add up to a significant amount of mileage a day. Just parking my car at the far end of the parking lot when I made a trip to the grocery store or taking the stairs rather than the elevator to my office on the third floor of the psychology building made the difference between getting in eight thousand steps a day and exceeding my goal of ten thousand.
The Fitbit is also a fun conversation starter. Because wearing the gadget signals that you are buying into the power of movement, it’s easy to strike up a conversation with strangers at restaurants and on the train who are wearing a similar device. Of course, most of the conversations I find myself engaged in with fellow Fitbitters have to do with how important exercise is for maintaining a healthy body. It’s rare that folks think about exercise in terms of benefiting the mind. Yet fitness contributes to both physical and mental health. Brains look and function differently according to whether they are housed in inactive or active bodies.
Exercise simulates the creation of new brain cells, a process known as neurogenesis.1 Some of the first research documenting the link between physical activity and the brain was done using mice. Mice raised in “enriched environments,” in which they had toys, exercise wheels, and lots of opportunities for social interaction, grew more new brain cells than their litter mates housed in standard laboratory cages. Scientists weren’t actually sure which part of the mice’s surroundings caused the new cell growth, so, in the late 1990s, researchers at the Salk Institute at the University of California, San Diego, conducted studies to find out. They systematically examined the different parts of the mice’s environment in order to unveil what exactly was responsible for the neurogenesis.2
The experiment that conclusively demonstrated the striking power of exercise on brain function followed a simple protocol. The scientists began by giving all of their young mice a chemical that could track the brain cells when they divided and new cells were produced. They then offered some mice access to “exercise equipment”—a running wheel that they could use as often as they liked. Another group of mice didn’t have the opportunity to exercise and led a fairly inactive lifestyle. After several weeks, the scientists sacrificed the rodents so they could see if and how the brains of the two groups differed. They found striking differences: those mice that had been on the move had more new brain cells, roughly twice as many, compared to their sedentary counterparts.
To make sure it was the vigorous exercise that had changed the mice’s brains, the Salk researchers enrolled another group of mice in their study. The mice in this new group learned how to navigate a maze. They had a lot of mental exertion but not as much physical activity as their wheel-running counterparts. Surprisingly, the opportunity to expend cognitive effort didn’t lead to nearly as much proliferation of new brain cells as running did. The lesson here? Even though we are often tired after a long day of work and it feels as though we have run a marathon, it’s not the same as actually hitting the track—at least to our brains. Vigorous exercise is important for growing new brain cells.
The mobile mice showed the most new
cell growth in a seahorse-shaped area deep inside the head, the hippocampus. This is one of the major brain centers that helps mice and men turn what we learn into long-lasting memories.
Fit Children
The brain has an impressive plasticity, particularly in childhood, and physical activity can improve kids’ mental functioning. Charles Hillman, a professor at the University of Illinois, has devoted much of his research career to documenting the power of exercise in altering kids’ brainpower. His work clearly shows that the time spent on physical activity does not come at the expense of academic achievement; rather fitness enhances what kids can do in the classroom.
In a recent study, Hillman and his colleague Art Kramer and their research team pulled together data on the physical fitness of a group of nine-and ten-year-olds. They scanned the children’s brains as the kids completed a series of cognitive challenges designed to test their thinking, reasoning, and memory skills and found that the fittest kids performed best on many of the memory tests. Even more telling, children’s physical fitness level roughly corresponded to the size of their hippocampus. Just like the wheel-running mice, the fittest kids had the most developed hippocampus.3
To further validate the link between a fit body and a fit mind, Hillman and Kramer also tested whether they could actually find direct benefits from a session of exercise on young kids’ brain functioning.4 The researchers asked a group of children to visit their laboratory on two separate occasions. During one visit, the children took part in a short bout of exercise: twenty minutes of walking at a fairly vigorous pace on a treadmill. On the second visit, the kids rested, sitting quietly in a chair, for twenty minutes. On each visit, after the kids had either rested or exercised (and the heart rates of the kids who had exercised had returned to normal), they were given a series of cognitive challenges. In one challenge, they were told to focus on one critical piece of information presented on a computer screen and ignore anything else that popped up. This mental activity is not unlike a situation a child might face when doing homework and the cell phone pings with a text message from a friend. To successfully complete the schoolwork, the child must focus on the academic material and ignore the tempting distraction. It’s also similar to concentrating on an exam and not letting your mind wander to thoughts of what you are going to do with your friends after school. The mental challenges in the experiment, in other words, mimicked the focus that kids need to maintain in order to succeed in school.