The Science of Fear: How the Culture of Fear Manipulates Your Brain

by Daniel Gardner

“This is preeminently the time to speak the truth, the whole truth, frankly and boldly. Nor need we shrink from honestly facing conditions in our country today. This great nation will endure as it has endured, will revive and will prosper. So, first of all, let me assert my firm belief that the only thing we have to fear is fear itself—nameless, unreasoning, unjustified terror which paralyzes needed efforts to convert retreat into advance.” Of

It’s an insight older than the United States itself. Roosevelt’s line was lifted from Henry David Thoreau, and Thoreau in turn got it from Michel de Montaigne, who wrote “the thing I fear most is fear” more than three and a half centuries ago.

Fear can be a constructive emotion. When we worry about a risk, we pay more attention to it and take action where warranted. Fear keeps us alive and thriving. It’s no exaggeration to say that our species owes its very existence to fear. But “unreasoning fear” is another matter. It was unreasoning fear that could have destroyed the United States in the Great Depression. It was unreasoning fear that killed 1,595 people by convincing them to abandon planes for cars after the September 11 attacks. And it is the growing presence of unreasoning fear in all the countries of the Western world that is causing us to make increasingly foolish decisions in dealing with the risks we face every day.

Risk and fear are hot topics among sociologists, who have come to a broad consensus that those of us living in modern countries worry more than previous generations. Some say we live in a culture of fear. Terrorists, Internet stalkers, crystal meth, avian flu, genetically modified organisms, contaminated food: New threats seem to sprout like poisonous mushrooms. Climate change, carcinogens, leaky breast implants, the “obesity epidemic,” pesticides, West Nile virus, SARS, avian flu, and flesh-eating disease. The list goes on and on. Open the newspaper, watch the evening news. On any given day, there’s a good chance that someone—a journalist, activist, consultant, corporate e...

The millennium bug was a bust, but that hasn’t stopped theories of annihilation from piling up so quickly it’s become almost commonplace to hear claims that humanity will be lucky to survive the next century. Ulrich Beck isn’t quite that pessimistic. As the German sociologist and professor at the London School of Economics told The Guardian newspaper, he merely thinks it “improbable” that humanity will survive “beyond the 21st century without a lapse back into barbarism.” Beck’s opinion counts more than most because he was among the first to realize that modern countries were becoming nations of worriers. Back in 1986, he coined the term “risk society” to describe countries in which there is heightened concern about risk—particularly risks caused by modern technology—and where people are frightened like never before.

Why should we worry more than previous generations? Ulrich Beck thinks the answer is clear: We are more afraid than ever because we are more at risk than ever. Technology is outstripping our ability to control it. The environment is collapsing. Social pressures are growing. The threat of cataclysm looms and people—like deer catching the scent of approaching wolves—sense the danger. Many others agree with Beck. Peering into the future and imagining all the ways things could go horribly wrong has become something of a parlor game for intellectuals.

A little more attention to history would also reveal that there have always been people crying “Doom!”—almost none of whom turned out to have any more ability to see into the future than the three blind mice of nursery-rhyme fame.

Humans in the developed world have undergone “a form of evolution that is unique not only to humankind, but unique among the 7,000 or so generations of humans who ever inhabited the earth,” Robert Fogel, a Nobel laureate at the University of Chicago, told The New York Times. The good fortune of those alive today, and the promise of more to come, is summed up in the title of one of Fogel’s books: The Escape from Hunger and Premature Death, 1700–2100.

At the century’s end, there were 120, and almost two-thirds of the people in the world could cast a meaningful ballot. As for the bloodshed and chaos that many people claim to see rising all around us, it just isn’t so. “War between countries is much less likely than ever and civil war is less likely than at any time since 1960,” Monty Marshall of George Mason University told The New York Times in 2005. A major study released later that year by the Human Security Centre at the University of British Columbia confirmed and expanded on that happy conclusion.

In the two decades following 1980, the proportion of people in the developing world who were malnourished fell from 28 percent to 17 percent. That’s still unconscionably high, but it’s a lot better than it was. Then there’s the United Nations Human Development Index (HDI). It’s probably the best measure of the state of humanity because it combines key data on income, health, and literacy. At the bottom of the HDI list of 177 countries is the African country of Niger—and yet Niger’s 2003 HDI score is 17 percent higher than it was in 1975. The same trend can be seen in almost all very poor countries. Mali is 31 percent better off. Chad is up 22 percent. Doom-mongers like to point to the soaring populations of the poor world as a potential source of future catastrophe, but what the doomsters never mention is that those populations aren’t soaring because women are having far more babies than in the past. It’s that their babies are far less likely to die than in the past—which everybody but the grumpiest Malthusian would consider to be very good news. Put all these numbers together and what do they add up to? In a sentence: We are the healthiest, wealthiest, and longest-lived people in history. And we are increasingly afraid. This is one of the great paradoxes of our time.

it’s important to understand why we so often get risk wrong. Why do we fear a proliferating number of relatively minor risks? Why do we so often shrug off greater threats? Why have we become a “culture of fear”?

Part of the answer lies in self-interest. Fear sells. Fear makes money. The countless companies and consultants in the business of protecting the fearful from whatever they may fear know it only too well. The more fear, the better the sales. So we have home-alarm companies frightening old ladies and young mothers by running ads featuring frightened old ladies and young mothers. Software companies scaring parents with hype about online pedophiles. Security consultants spinning scenarios of terror and death that can be avoided by spending more tax dollars on security consultants. Fear is a fantastic marketing tool, which is why we can’t turn on the television or open a newspaper without seeing it at work.

For social conservatives, that cluster of leaves is a symbol of the anarchic liberalism they despise, and they will consider any evidence that marijuana causes harm to be vindication—while downplaying or simply ignoring evidence to the contrary. Psychologists call this confirmation bias. We all do it. Once a belief is in place, we screen what we see and hear in a biased way that ensures our beliefs are “proven” correct. Psychologists have also discovered that people are vulnerable to something called group polarization—which means that when people who share beliefs get together in groups, they become more convinced that their beliefs are right and they become more extreme in their views. Put confirmation bias, group polarization, and culture together, and we start to understand why people can come to completely different views about which risks are frightening and which aren’t worth a second thought.

The real starting point for understanding why we worry and why we don’t is the individual human brain. Four decades ago, scientists knew little about how humans perceived risks, how we judged which risks to fear and which to ignore, and how we decided what to do about them. But in the 1960s, pioneers like Paul Slovic, today a professor at the University of Oregon, set to work. They made startling discoveries, and over the ensuing decades, a new body of science grew. The implications of this new science were enormous for a whole range of different fields. In 2002, one of the major figures in this research, Daniel Kahneman, won the Nobel Prize in economics, even though Kahneman is a psychologist who never took so much as a single class in economics. What the psychologists discovered is that a very old idea is right. Every human brain has not one but two systems of thought. They called them System One and System Two. The ancient Greeks—who arrived at this conception of humanity a little earlier than scientists—personified the two systems in the form of the gods Dionysus and Apollo. We know them better as Feeling and Reason. System Two is Reason. It works slowly. It examines evidence. It calculates and considers. When Reason makes a decision, it’s easy to put into words and explain. System One—Feeling—is entirely different. Unlike Reason, it works without our conscious awareness and is as fast as lightning. Feeling is the source of the snap judgments that we experience as a hu...

What System One did is apply a simple rule of thumb: If examples of something can be recalled easily, that thing must be common. Psychologists call this the “availability heuristic.” Obviously, System One is both brilliant and flawed. It is brilliant because the simple rules of thumb System One uses allow it to assess a situation and render a judgment in an instant—which is exactly what you need when you see a shadow move at the back of an alley and you don’t have the latest crime statistics handy. But System One is also flawed because the same rules of thumb can generate irrational conclusions.

The problem is that System One wasn’t created for the world we live in. For almost the entire history of our species and those that came before, our ancestors lived in small nomadic bands that survived by hunting animals and gathering plants. It was in that long and long-ago era that evolution shaped and molded System One. Having been forged by that environment, System One works quite well in it. But today, very few human beings spend their days stalking antelope and avoiding lions. We live in a world transformed by technology—a world in which risks are measured in microns and parts-per-million and we are bombarded with images and information from all over the planet.

The transformation of the human brain into its modern form occurred entirely during the “Old Stone Age”—the Paleolithic era that lasted from roughly two million years ago until the introduction of agriculture some 12,000 years ago. Not that the advent of agriculture suddenly transformed how most people lived. It took thousands of years for the new way of life to spread, and it was only 4,600 years ago that the first city—not much more than a town by modern standards—was founded. If the history of our species were written in proportion to the amount of time we lived at each stage of development, two hundred pages would be devoted to the lives of nomadic hunter-gatherers. One page would cover agrarian societies. The world of the last two centuries—the modern world—would get one short paragraph at the end. Our brains were simply not shaped by life in the world as we know it now, or even the agrarian world that preceded it. They are the creation of the Old Stone Age. And since our brains really make us what we are, the conclusion to be drawn from this is unavoidable and a little unsettling. We are cavemen. Or cavepersons, if you prefer. Whatever the nomenclature, we sophisticated moderns living in a world of glass, steel, and fiber optics are no different, in a fundamental sense, than the prehistoric humans for whom campfires were the latest in high tech and bison hides were haute couture.

One bit of very old wiring is sometimes called the Law of Similarity. In the late nineteenth century, anthropologists noticed that traditional cultures assumed that causes resembled their effects. The Zande people of Africa, for example, believed that ringworm was caused by fowl excrement because fowl excrement looks like ringworm. In European folk medicine, foxes were felt to have great stamina and so their lungs were used to treat asthma, while Chinese folk medicine treated eyesight ailments with ground-up bat eyes because it was (quite wrongly) believed that bats had superior eyesight. The fact that this same assumption—like causes like—could be found in culture after culture, all over the world, is a very strong indication that it has biological origins. The Law of Similarity comes in an even more basic form: Appearance equals reality. If it looks like a lion, it is a lion. Or, to put it in the modern vernacular, if it walks like a duck and quacks like a duck, it’s a duck. That may seem more like common sense than ancient wiring, but it is quite ancient. And it’s not always so sensible.

And when they asked students to choose an empty container, fill it with sugar, and label it SODIUM CYANIDE, POISON, the students shrank from consuming the sugar. “In these studies,” wrote psychologists Paul Rozin and Carol Nemeroff, “subjects realized that their negative feelings were unfounded, but they felt and acknowledged them anyway.”

This seems absurd only from the perspective of a modern human. For Paleolithic man, the appearance-equals-reality rule was useful and reliable. He could be quite confident that if he saw something that looked like his children, it was his children. Only when the environment changed as a result of the invention of photography would humans see images that looked like their children but were not their children—and that happened only 180 years ago.

System One, or Gut, is unconscious thought, and its defining quality is speed. Gut doesn’t need an encyclopedia to figure out what to do when something moves in the long grass. It makes a snap judgment and sounds the alarm instantly. There’s a twinge in your stomach. Your heart beats a little faster. Your eyes zero in. “The heart has its reasons,” Blaise Pascal wrote more than three centuries ago, “which reason knows nothing of.”

“Heuristics and biases” is the rather opaque name for one of the most exciting efforts to tease out the secrets of thinking. In this case, “bias” isn’t meant to be an insult. It’s a tendency, nothing more. If you read a shopping list on which one of the items is written in green ink while all the rest are blue, you will tend to remember the one green item. That’s the Von Restorff effect—a bias in favor of remembering the unusual. It’s only one of a long list of biases uncovered by psychologists. Some—like the Von Restorff effect—are pretty obvious. Others are more surprising, as we will see.

In fact, psychologists have demonstrated that even the toughest skeptics will find it difficult, or even impossible, to keep bogus statistics from worming into their brains and influencing their judgments.

In some studies, researchers have even told people that the number they heard is irrelevant and specifically asked them not to let it influence their judgment. Still, it did. What’s happening here is that Gut is using something psychologists call the anchoring and adjustment heuristic, or what I’ll call the Anchoring Rule. When we are uncertain about the correct answer and we make a guess, Gut grabs hold of the nearest number—which is the most recent number it heard. Head then adjusts but “adjustments tend to be insufficient,” write psychologists Nicholas Epley and Thomas Gilovich, “leaving people’s final estimates biased toward the initial anchor value.”

The Anchoring Rule is rich with possibilities for manipulation. Retail sales are an obvious example. A grocery store that wants to sell a large shipment of tomato soup in a hurry can set up a prominent display and top it off with a sign that reads LIMIT 12 PER CUSTOMER, or BUY 18 FOR YOUR CUPBOARD. The message on the sign isn’t important. Only the number is.

The Anchoring Rule can also be used to skew public opinion surveys to suit one’s purposes. Say you’re the head of an environmental group and you want to show that the public supports spending a considerable amount of money cleaning up a lake. You do this by conducting a survey that begins with a question about whether the respondent would be willing to contribute some money—say $200—to clean up the lake. Whether people say yes or no doesn’t matter. You’re asking this question only to get the figure $200 into people’s heads. It’s the next question that counts: You ask the respondent to estimate how much the average person would be willing to pay to clean up the lake. Thanks to the Anchoring Rule, you can be sure the respondent’s Gut will start at $200 and adjust downward, arriving at a figure that will still be higher than it would have been if that figure hadn’t been handed to Gut. In a study that did precisely this, psychologists Daniel Kahneman and Jack Knetsch found that the average guess about how much people would be willing to pay to clean up the lake was $36. But in a second trial, the $200 figure was replaced with $25. When people were then asked how much others would be willing to pay to clean up the lake, the average guess was a mere $14. Thus a high anchoring number produced an average answer almost 150 percent greater than a low number. By now, the value of the Anchoring Rule to someone marketing fear should be obvious.

As always in science, there are many authors and origins of this burgeoning field, but two who stand out are psychologists Daniel Kahneman and Amos Tversky. Four decades ago, Kahneman and Tversky collaborated on research that looked at how people form judgments when they’re uncertain of the facts. That may sound like a modest little backwater of academic work, but it is actually one of the most basic aspects of how people think and act. For academics, it shapes the answers to core questions in fields as diverse as economics, law, health, and public policy. For everyone else, it’s the stuff of daily life: what jobs we take; who we marry; where we live; whether we have children, and how many. It’s also crucial in determining how we perceive and respond to the endless list of threats—from choking on toast to the daily commute to terrorist attacks—that could kill us. When Kahneman and Tversky began their work, the dominant model of how people make decisions was that of Homo economicus. “Economic man” is supremely rational. He examines evidence. He calculates what would best advance his interests as he understands them, and he acts accordingly. The Homo economicus model ruled economics departments and was hugely influential in public policy circles as well, in part because it suggested that influencing human behavior was actually rather simple. To fight crime, for example, politicians need only make punishments tougher. When the potential costs of crime outweigh the potential b...

In 1957, Herbert Simon, a brilliant psychologist/economist/political scientist and future Nobel laureate, coined the term bounded rationality. We are rational, in other words, but only within limits. Kahneman and Tversky set themselves the task of discovering those limits. In 1974, they gathered together several years’ work and wrote a paper with the impressively dull title of “Judgment Under Uncertainty: Heuristics and Biases.” They published it in Science, rather than a specialist journal, because they thought some of the insights might be interesting to non-psychologists. Their little paper caught the attention of philosophers and economists and a furious debate began. It lasted for decades, but Kahneman and Tversky ultimately prevailed.

a dynamic new field called “behavioral economics” is devoted to bringing the insights of psychology to economics.

Kahneman and Tversky didn’t say anything about rationality. They didn’t call Homo economicus a myth. All they did was lay out solid research that revealed some of the heuristics—the rules of thumb—that Gut uses to make judgments, such as guessing how old Gandhi was when he died or whether it’s safe to drive to work. Today, Kahneman thinks that’s one reason that the article was as influential as it was.

Gut is a sucker for a good story.

But for most people, Gut is far more persuasive than mere logic. Kahneman and Tversky realized what this meant for expert predictions. “This effect contributes to the appeal of scenarios and the illusory insight that they often provide,” they wrote. “A political analyst can improve scenarios by adding plausible causes and representative consequences. As Pooh-Bah in The Mikado explains, such additions provide ‘corroborative details intended to give artistic verisimilitude to an otherwise bald and unconvincing narrative.’ ”

One of Gut’s simplest rules of thumb is that the easier it is to recall examples of something, the more common that something must be. This is the “availability heuristic,” which I call the Example Rule. Kahneman and Tversky demonstrated the influence of the Example Rule in a typically elegant way. First, they asked a group of students to list as many words as they could think of that fit the form _ _ _ _ _ n _. The students had 60 seconds to work on the problem. The average number of words they came up with was 2.9. Then another group of students was asked to do the same, with the same time limit, for words that fit the form _ _ _ _ ing. This time, the average number of words was 6.4. Look carefully and it’s obvious there’s something strange here. The first form is just like the second, except the letters “i” and “g” have been dropped. That means any word that fits the second form must fit the first. Therefore, the first form is actually more common. But the second form is much more easily recalled.

The more easily people are able to think of examples of something, the more common they judge that thing to be.

In a revealing study, psychologists Alexander Rothman and Norbert Schwarz asked people to list either three or eight behaviors they personally engage in that could increase their chance of getting heart disease. Strangely, those who thought of three risk-boosting behaviors rated their chance of getting heart disease to be higher than those who thought of eight. Logically, it should be the other way around—the longer the list, the greater the risk. So what gives? The explanation lies in the fact—which Rothman and Schwarz knew from earlier testing—that most people find it easy to think of three factors that increase the risk of heart disease but hard to come up with eight. And it is the ease of recall, not the substance of what is recalled, that guides the intuition.

The Rothman and Schwarz study also demonstrated how complex and subtle the interaction of Head and Gut can be. The researchers divided people into two groups: those who had a family history of heart disease and those who didn’t. For those who did not have a family history, the results were as outlined above. But those who did have a family history of heart disease got precisely the opposite results: Those who struggled to come up with eight risk-boosting behaviors they engage in rated their chance of getting heart disease to be higher than those who thought of three examples. Why the different result? People with no family history of heart disease have no particular cause for worry and nothing to base their judgment on, so they are more casual in their judgment and they go with the estimate that Gut comes up with using the Example Rule. But people with a family history of heart disease have a very compelling reason to think hard about this, and when they do, Head tells them that Gut is wrong—that, logically, if you engage in eight risk-boosting behaviors, your risk is higher than if you engage in three such behaviors.

As a rule of thumb for hunter-gatherers walking the African savanna, the Example Rule makes good sense. That’s because the brain culls low-priority memories: If time passes and a memory isn’t used, it is likely to fade. So if you have to think hard to remember that, yes, there was a time when someone got sick after drinking from that pond, chances are it happened quite a while ago and a similar incident hasn’t happened since—making it reasonable to conclude that the water in the pond is safe to drink. But if you instantly recall an example of someone drinking that water and turning green, then it likely happened recently and you should find somewhere else to get a drink. This is how Gut makes use of experience and memory.

In each case, the amygdala, a lump of brain shaped like an almond, will trigger the release of hormones, including adrenaline and cortisol. Your pupils dilate, your heart races, your muscles tense. This is the famous fight-or-flight response. It is intended to generate a quick reaction to immediate threats but it also contains one element intended to have a lasting effect: The hormones the amygdala triggers temporarily enhance memory function so the awful experience that triggered the response will be vividly encoded and remembered. Such traumatic memories last, and they are potent. Long after calm has returned, even years later in some cases, they are likely to be recalled with terrifying ease. And that fact alone will cause Gut to press the alarm that we experience as an uneasy sense of threat.

There is obvious survival value in remembering personal experiences of risk. But even more valuable for our ancient ancestors—and us, too—is the ability to learn and remember from the experiences of others. After all, there’s only one of you. But when you sit around the campfire after a long day of foraging, there may be twenty or thirty other people. If you can gather their experiences, you will multiply the information on which your judgments are based twenty or thirty times. Sharing experiences means telling stories. It also means visualizing the event the guy next to you at the campfire is telling you about: imagining the dimmest member of the tribe wading into the shallow waters of the river; imagining him poking a floating log with his walking stick; imagining the log suddenly turning into a crocodile; imagining the trail of bubbles that marks the demise of the tribe’s dimmest member. Having envisioned the scene and committed it to memory, Gut can then use it to make judgments just as it uses memories from personal experiences. Risk of crocodile attack at water’s edge?

Gut has learned from someone else’s tragic experience.

An event that comes from a story told by the person who actually experienced it provides valuable, real-world experience. But an imagined scene that was invented by the storyteller is something else entirely. It’s fiction. Gut should treat it accordingly, but it does not.

It’s not merely the act of imagining that raises Gut’s estimate of how likely something is, it’s how easy it is to imagine that thing.

If imagining is easy, Gut’s estimate goes up. But if it is a struggle to imagine, it will feel less likely for that reason alone.

A more basic problem with the Example Rule is that it is biased, thanks to the way our memories work. Recent, emotional, vivid, or novel events are all more likely to be remembered than others. In most cases, that’s fine because it’s precisely those sorts of events that we actually need to remember. But the bias in our memory will be reflected in Gut’s judgments using the Example Rule—which explains the paradox of people buying earthquake insurance when the odds of an earthquake are lowest and dropping it as the risk rises. If an earthquake recently shook my city, that memory will be fresh, vivid, and frightening. Gut will shout: Be afraid! Buy insurance! But if I’ve been living in this place for decades and there has never been an earthquake, Gut will only shrug. Not even scientists issuing warnings will rouse Gut because it doesn’t know anything about science. It knows only what the Example Rule says, and the Example Rule says don’t worry about earthquakes if you have to struggle to remember one happening.

The first city, Ur, was founded only 4,600 years ago and never got bigger than 65,000 people. Today, half of all humans live in cities—more than 80 percent in some developed countries.

We have brains that defy logic by using the Rule of Typical Things to conclude that elaborate predictions of the future are more likely to come true than simple predictions. At a time when we are constantly warned about frightening future developments, this, too, is not helpful. Most important, we have brains that use the Example Rule to conclude that being able to easily recall examples of something happening proves that it is likely to happen again. For ancient hunters stalking wildebeest on the savanna, that wasn’t a bad rule. In an era when tourists can e-mail video of a tsunami to the entire planet in less time than it takes the wreckage to dry, it has the potential to drive us mad. Should we fear exotic viruses? Terrorists? Pedophiles stalking kids on the Internet? Any of the other items on the long and growing list of worries that consume us?

One of the most consistent findings of risk-perception research is that we overestimate the likelihood of being killed by the things that make the evening news and underestimate those that don’t. What makes the evening news? The rare, vivid, and catastrophic killers. Murder, terrorism, fire, and flood. What doesn’t make the news is the routine cause of death that kills one person at a time and doesn’t lend itself to strong emotions and pictures. Diabetes, asthma, heart disease.

we see movies and TV dramas as nothing more than entertainment, so we approach them with lowered critical faculties: Gut watches while Head sleeps. Unfortunately, almost no research has examined how fiction affects risk perception. One recent study, however, found just what psychologists would expect. Anthony Leiserowitz of Decision Research (a private research institute founded by Paul Slovic, Sarah Lichtenstein, and Baruch Fischhoff) conducted cross-country surveys in the United States before and after the release of The Day After Tomorrow, a disaster film depicting a series of sudden, spectacular catastrophes unleashed by global warming. The science in The Day After Tomorrow is dubious, to say the least. Not even the most frightening warnings about the effects of global warming come close to what the movie depicts. But that made no difference to the influence of the film. Across the board, more people who saw the film said they were concerned about global warming, and when they were asked how likely it was that the United States would experience various disasters similar to those depicted in the movie—flooded cities, food shortages, Gulf Stream shutdown, a new Ice Age, etc.—people who had seen the movie consistently rated these events more likely than those who didn’t. The effects remained even after the numbers were adjusted to account for the political leanings of respondents. Of course, Head can always step in, look at the evidence, and overrule. As we have seen, it ...

Philosophers and scholars may debate the nature of justice, but for most of us justice is experienced as outrage at a wrong and satisfaction at the denunciation and punishment of that wrong. It is a primal emotion. The woman who murdered her little boy must be punished. It doesn’t matter that she isn’t a threat to anyone else. This isn’t about safety. She must be punished. Evolutionary psychologists argue that this urge to punish wrongdoing is hardwired because it is an effective way to discourage bad behavior. “People who are emotionally driven to retaliate against those who cross them, even at a cost to themselves, are more credible adversaries and less likely to be exploited,” writes cognitive psychologist Steven Pinker.

Even subtle changes in language can have considerable impact. Paul Slovic and his team gave forensic psychiatrists—men and women trained in math and science—what they were told was another clinician’s assessment of a mental patient confined to an institution. Based on this assessment, the psychiatrists were asked, would you release this patient? Half the assessments estimated that patients similar to Mr. Jones “have a 20 percent chance of committing an act of violence” after release. Of the psychiatrists who read this version, 21 percent said they would refuse to release the patient. The wording of the second version of the assessment was changed very slightly. It is estimated, the assessment said, that “20 out of every 100 patients similar to Mr. Jones” will be violent after release. Of course, “20 percent” and “20 out of every 100” mean the same thing. But 41 percent of the psychiatrists who read this second version said they would keep the patient confined, so an apparently trivial change in wording boosted the refusal rate by almost 100 percent. How is that possible? The explanation lies in the emotional content of the phrase “20 percent.” It’s hollow, abstract, a mere statistic. What’s a “percent”? Can I see a “percent”? Can I touch it? No. But “20 out of every 100 patients” is very concrete and real.