By Paul Bloom

How do Americans spend their leisure time? The answer might surprise you. The most common voluntary activity is not eating, drinking alcohol, or taking drugs. It is not socializing with friends, participating in sports, or relaxing with the family. While people sometimes describe sex as their most pleasurable act, time-management studies find that the average American adult devotes just four minutes per day to sex.

Our main leisure activity is, by a long shot, participating in experiences that we know are not real. When we are free to do whatever we want, we retreat to the imagination—to worlds created by others, as with books, movies, video games, and television (over four hours a day for the average American), or to worlds we ourselves create, as when daydreaming and fantasizing. While citizens of other countries might watch less television, studies in England and the rest of Europe find a similar obsession with the unreal.

This is a strange way for an animal to spend its days. Surely we would be better off pursuing more adaptive activities—eating and drinking and fornicating, establishing relationships, building shelter, and teaching our children. Instead, 2-year-olds pretend to be lions, graduate students stay up all night playing video games, young parents hide from their offspring to read novels, and many men spend more time viewing Internet pornography than interacting with real women. One psychologist gets the puzzle exactly right when she states on her Web site: "I am interested in when and why individuals might choose to watch the television show Friends rather than spending time with actual friends."

One solution to this puzzle is that the pleasures of the imagination exist because they hijack mental systems that have evolved for real-world pleasure. We enjoy imaginative experiences because at some level we don't distinguish them from real ones. This is a powerful idea, one that I think is basically—though not entirely—right. (Certain phenomena, including horror movies and masochistic daydreams, require a different type of explanation.)

The capacity for imaginative pleasure is universal, and it emerges early in development. All normal children, everywhere, enjoy playing and pretending. There are cultural differences in the type and frequency of play. A child in New York might pretend to be an airplane; a hunter-gatherer child will not. In the 1950s, American children played Cowboys and Indians; not so much anymore. In some cultures, play is encouraged; in others, children have to sneak off to do it. But it is always there. Failure to play and pretend is a sign of a neurological problem, one of the early symptoms of autism.

Developmental psychologists have long been interested in children's appreciation of the distinction between pretense and reality. We know that children who have reached their fourth birthday tend to have a relatively sophisticated understanding, because when we ask them straight out about what is real and what is pretend, they tend to get it right. What about younger children? Two-year-olds pretend to be animals and airplanes, and they can understand when other people do the same thing. A child sees her father roaring and prowling like a lion, and might run away, but she doesn't act as though she thinks her father is actually a lion. If she believed that, she would be terrified. The pleasure children get from such activities would be impossible to explain if they didn't have a reasonably sophisticated understanding that the pretend is not real.

It is an open question how early this understanding emerges, and there is some intriguing experimental work exploring this. My own hunch is that even babies have some limited grasp of pretense, and you can see this from casual interaction. A useful way to spend time with a 1-year-old is to put your face up close and wait for the baby to grab at your glasses or nose or hair. Once there is contact, pull your head back and roar in mock rage. The first time you get a bit of surprise, maybe concern, a dash of fear, but then you put your head back and wait for the baby to try again. She will, and then you give the pretend-startled response. Many babies come to find this hilarious. (If the baby is an eye-poker, you can wrestle over keys instead.) For this to work, though, the baby has to know that you are not even a little bit angry; the baby must know that you are pretending.

Why do we get pleasure from the imagination? Isn't it odd that toddlers enjoy pretense, and that children and adults are moved by stories, that we have feelings about characters and events that we know do not exist? As the title of a classic philosophy article put it, how can we be moved by the fate of Anna Karenina?

The emotions triggered by fiction are very real. When Charles Dickens wrote about the death of Little Nell in the 1840s, people wept—and I'm sure that the death of characters in J.K. Rowling's Harry Potter series led to similar tears. (After her final book was published, Rowling appeared in interviews and told about the letters she got, not all of them from children, begging her to spare the lives of beloved characters such as Hagrid, Hermione, Ron, and, of course, Harry Potter himself.) A friend of mine told me that he can't remember hating anyone the way he hated one of the characters in the movie Trainspotting, and there are many people who can't bear to experience certain fictions because the emotions are too intense. I have my own difficulty with movies in which the suffering of the characters is too real, and many find it difficult to watch comedies that rely too heavily on embarrassment; the vicarious reaction to this is too unpleasant.

These emotional responses are typically muted compared with the real thing. Watching a movie in which someone is eaten by a shark is less intense than watching someone really being eaten by a shark. But at every level—physiological, neurological, psychological—the emotions are real, not pretend.

Does this suggest that people believe, at some level, that the events are real? Do we sometimes think that fictional characters actually exist and fictional events actually occur? Of course, people get fooled, as when parents tell their children about Santa Claus, the Tooth Fairy, and the Easter Bunny, or when an adult mistakes a story for a documentary, or vice versa. But the idea here is more interesting than that—it is that even once we consciously know something is fictional, there is a part of us that believes it's real.

There is something to this: It can be devilishly hard to pull apart fiction from reality. There are several studies showing that reading a fact in a story—and knowing that it is fiction—increases the likelihood that you believe the fact to be true. And this makes sense, because stories are mostly true. If you were to read a novel that takes place in London toward the end of the 1980s, you would learn a lot about how people in that time and place talked to one another, what they ate, how they swore, and so on, because any decent storyteller has to include these truths as a backdrop for the story. The average person's knowledge of law firms, emergency rooms, police departments, prisons, submarines, and mob hits is not rooted in real experience or nonfictional reports. It is based on stories. Someone who watched cop shows on television would absorb many truths about contemporary police work ("You have the right to remain silent . . ."), and a viewer of a realistic movie such as Zodiac would learn more. Indeed, many people seek out certain types of fiction (historical novels, for example) because they want a painless way of learning about reality.

We go too far sometimes. Fantasy can be confounded with reality. For example, the publication of The Da Vinci Code led to a booming tourism industry in Scotland, by people accepting the novel's claims about the location of the Holy Grail. Then there is the special problem of confusing actors with the characters they play. Leonard Nimoy, an actor born in Boston to Yiddish-speaking Russian immigrants, was frequently confused with his best-known role, Mr. Spock, from the planet Vulcan. This was sufficiently frustrating that he published a book called I Am Not Spock (and then, 20 years later, published I Am Spock). Or consider the actor Robert Young, star of one of the first medical programs, Marcus Welby, M.D., who reported getting thousands of letters asking for medical advice. He later exploited this confusion by appearing in his doctor persona (wearing a white lab coat) on television commercials for aspirin and decaffeinated coffee. There is, then, an occasional blurring between fact and reality.

In the end, though, those brought to tears by Anna Karenina are perfectly aware that she is a character in a novel; those people who wailed when J.K. Rowling killed off Dobby the House Elf knew full well that he doesn't exist. And even young children appreciate the distinction between reality and fiction; when you ask them, "Is such-and-so real or make-believe?," they get it right.

Why, then, are we so moved by stories?

David Hume tells the story of a man who is hung out of a high tower in a cage of iron. He knows himself to be perfectly secure, but, still, he "cannot forebear trembling." Montaigne gives a similar example, saying that if you put a sage on the edge of a precipice, "he must shudder like a child." My colleague, the philosopher Tamar Gendler, describes the Grand Canyon Skywalk, a glass walkway that extends 70 feet from the canyon's rim. It is supposedly a thrilling experience. So thrilling

that some people drive several miles over a dirt road to get there and then discover that they are too afraid to step onto the walkway. In all of these cases, people know they are perfectly safe, but they are nonetheless frightened.

In an important pair of papers, Gend-ler introduces a novel term to describe the mental state that underlies these reactions: She calls it "alief." Beliefs are attitudes that we hold in response to how things are. Aliefs are more primitive. They are responses to how things seem. In the above example, people have beliefs that tell them they are safe, but they have aliefs that tell them they are in danger. Or consider the findings of Paul Rozin, a professor of psychology at the University of Pennsylvania, that people often refuse to drink soup from a brand-new bedpan, eat fudge shaped like feces, or put an empty gun to their head and pull the trigger. Gendler notes that the belief here is: The bedpan is clean, the fudge is fudge, the gun is empty. But the alief is stupid, screaming, "Filthy object! Dangerous object! Stay away!"

The point of alief is to capture the fact that our minds are partially indifferent to the contrast between events that we believe to be real versus those that seem to be real, or that are imagined to be real. This extends naturally to the pleasures of the imagination. Those who get pleasure voyeuristically watching real people have sex will enjoy watching actors having sex in a movie. Those who like observing clever people interact in the real world will get the same pleasure observing actors pretend to be such people on television. Imagination is Reality Lite—a useful substitute when the real pleasure is inaccessible, too risky, or too much work.

Often we experience ourselves as the agent, the main character, of an imaginary event. To use a term favored by psychologists who work in this area, we get transported. This is how daydreams and fantasies typically work; you imagine winning the prize, not watching yourself winning the prize. Certain video games work this way as well: They establish the illusion of running around shooting aliens, or doing tricks on a skateboard, through visual stimulation that fools a part of you into thinking—or alieving—that you, yourself, are moving through space.

For stories, though, you have access to information that the character lacks. The philosopher Noël Carroll gives the example of the opening scene in Jaws. You can't be merely taking the teenager's perspective as she swims in the dark, because she is cheerful, and you are terrified. You know things that she doesn't. You hear the famous, ominous music; she doesn't. You know that she is in a movie in which sharks eat people; she thinks that she is living a normal life.

This is how empathy works in real life. You would feel the same way seeing someone happily swim while a shark approaches her. In both fiction and reality, then, you simultaneously make sense of the situation from both the character's perspective and from your own.

Samuel Johnson, writing about Shakespeare, said: "The delight of tragedy proceeds from our consciousness of fiction; if we thought murders and treasons real, they would please no more." Johnson was a brilliant writer, but plainly he had never heard of O.J. Simpson. If he had, he'd realize that we get plenty of pleasure from real tragedy. Indeed, Shakespeare's tragedies depict precisely the sorts of events that we most enjoy witnessing in the real world—complex and tense social interactions revolving around sex, love, family, wealth, and status.

I have argued that our emotions are partially insensitive to the contrast between real versus imaginary, but it is not as if we don't care—real events are typically more moving than their fictional counterparts. This is in part because real events can affect us in the real world, and in part because we tend to ruminate about the implications of real-world acts. When the movie is finished or the show is canceled, the characters are over and done with. It would be odd to worry about how Hamlet's friends are coping with his death because these friends don't exist; to think about them would involve creating a novel fiction. But every real event has a past and a future, and this can move us. It is easy enough to think about the families of those people whom O.J. Simpson was accused of murdering.

But there are also certain compelling features of the imagination. Just as artificial sweeteners can be sweeter than sugar, unreal events can be more moving than real ones. There are three reasons for this.

First, fictional people tend to be wittier and more clever than friends and family, and their adventures are usually much more interesting. I have contact with the lives of people around me, but this is a small slice of humanity, and perhaps not the most interesting slice. My real world doesn't include an emotionally wounded cop tracking down a serial killer, a hooker with a heart of gold, or a wisecracking vampire. As best I know, none of my friends has killed his father and married his mother. But I can meet all of those people in imaginary worlds.

Second, life just creeps along, with long spans where nothing much happens. The O.J. Simpson trial lasted months, and much of it was deadly dull. Stories solve this problem—as the critic Clive James once put it, "Fiction is life with the dull bits left out." This is one reason why Friends is more interesting than your friends.

Finally, the technologies of the imagination provide stimulation of a sort that is impossible to get in the real world. A novel can span birth to death and can show you how the person behaves in situations that you could never otherwise observe. In reality you can never truly know what a person is thinking; in a story, the writer can tell you.

So while reality has its special allure, the imaginative techniques of books, plays, movies, and television have their own power. The good thing is that we do not have to choose. We can get the best of both worlds by taking an event that people know is real and using the techniques of the imagination to transform it into an experience that is more interesting and powerful than the normal perception of reality could ever be. The best example of this is an art form that has been invented in my lifetime, one that is addictively powerful, as shown by the success of shows such as The Real World, Survivor, The Amazing Race, and Fear Factor. What could be better than reality television?

Paul Bloom is a professor of psychology at Yale University. He is author of the forthcoming book, How Pleasure Works: The New Science of Why We Like What We Like (W.W. Norton & Company), from which this essay is adapted.