WE love a good story. Narrative is stitched intrinsically into the fabric of human psychology. But why? Is it all just fun and games, or does storytelling serve a biological function?

These questions animate "The Storytelling Animal," a jaunty, insightful new book by Jonathan Gottschall, who draws from disparate corners of history and science to celebrate our compulsion to storify everything around us.

There are several surprises about stories. The first is that we spend a great deal of time in fictional worlds, whether in daydreams, novels, confabulations or life narratives. When all is tallied up, the decades we spend in the realm of fantasy outstrip the time we spend in the real world. As Gottschall puts it, "Neverland is our evolutionary niche, our special habitat."

A second surprise: The dominant themes of story aren't what we might assume them to be. Consider the plotlines found in children's playtime, daydreams and novels. The narratives can't be explained away as escapism to a more blissful reality. If that were their purpose, they would contain more pleasure. Instead, they're horrorscapes. They bubble with conflict and struggle. The plots are missing all the real-life boring bits, and what remains is an unrealistically dense collection of trouble. Trouble, Gottschall argues, is the universal grammar of stories.

The same applies to our nighttime hallucinations. If you've ever wanted your dreams to come true, let's hope you don't mean your literal nocturnal dreams. These overflow with discord and violence. When researchers pick apart hours of dream content, it turns out dreamland is all about fight or flight.

What do these observations reveal about the function of story? First, they give credence to the supposition that story's job is to simulate potential situations. Neuroscience has long recognized that emulation of the future is one of the main businesses intelligent brains invest in. By learning the rules of the world and simulating outcomes in the service of decision-making, brains can play out events without the risk and expense of attempting them physically. As the philosopher Karl Popper wrote, simulation of the future allows "our hypotheses to die in our stead." Clever animals don't want to engage in the expensive and potentially fatal game of physically testing every action to discover its consequences. That's what story is good for. The production and scrutiny of counterfactuals (colloquially known as "what ifs") is an optimal way to test and refine one's behavior.

But storytelling may run even deeper than that. Remember, in "Star Wars," when Luke Skywalker precisely aims his proton torpedoes into the vent shaft of the Death Star? Of course you do. It's memorable because it's the climax of a grand story about good triumphing over evil. (You'd be less likely to recall a moment in which a protagonist files her nails while discussing her day.) More important, Luke's scene provides a good analogy: It's not easy to infect the brain of another person with an idea; it can be accomplished only by hitting the small exposed hole in the system. For the brain, that hole is story-shaped. As anyone who teaches realizes, most information bounces off with little impression and no recollection. Good professors and statesmen know the indispensable potency of story.

This is not a new observation, but nowadays we have a better understanding of why it's true. Changing the brain requires the correct neurotransmitters, and those are especially in attendance when a person is curious, is predicting what will happen next and is emotionally engaged. Hence successful religious texts are not written as nonfiction arguments or bulleted lists of claims. They are stories. Stories about burning bushes, whales, sons, lovers, betrayals and rivalries.

Story not only sticks, it mesmerizes. This is why WWE wrestling thrives on fake but exciting plotlines, why there are so many hours poured into prefight boxing hype, and why there are stirring backstories included in all the profiles of Olympic athletes. But not all stories are created equal. Gottschall points out that for a story to work, it has to possess a particular morality. To capture and influence, it can't be plagued with moral repugnance - involving, say, a sexual love story between a mother and her son, or a good guy who becomes crippled and a bad guy who profits handsomely. If the narrative doesn't contain the suitable kind of virtue, brains don't absorb it. The story torpedo misses the exposed brain vent. (There are exceptions, Gottschall allows, but they only prove the rule.)

This leads to the suggestion that story's role is "intensely moralistic." Stories serve the biological function of encouraging pro-social behavior. Across cultures, stories instruct a version of the following: If we are honest and play by the social rules, we reap the rewards of the protagonist; if we break the rules, we earn the punishment accorded to the bad guy. The theory is that the urge to produce and consume moralistic stories is hard-wired into us, and this helps bind society together. As such, stories are as important as genes. They're not time wasters; they're evolutionary innovations.

Suppressing selfishness

Gottschall highlights this social-binding property in the stories nations tell about themselves. Full of inaccuracies, these are "mostly fiction, not history," he writes. They accomplish the same evolutionary function as religion: defining groups, coordinating behavior and suppressing selfishness in favor of cooperation. Our national myths "tell us that not only are we the good guys," Gottschall writes, "but we are the smartest, boldest, best guys that ever were."

Unlike WH Auden, who worried that "poetry makes nothing happen," Gottschall, who teaches English at Washington and Jefferson College in Pennsylvania, feels certain that fiction can change the world. Consider the influence of Wagner's operas on Hitler's self-vision, or the effect of "Uncle Tom's Cabin" on American culture. "Research shows that story is constantly nibbling and kneading us," Gottschall writes. "If the research is correct, fiction is one of the primary sculpting forces of individuals and societies."

Recent fare like "The Shallows" and "The Dumbest Generation" lament our descent into the end of literature. But not so fast, Gottschall says: Storytelling is neither dead nor dying. As for the attention-demanding novel? "Rumors of its demise are exaggerated to the point of absurdity," he writes. "In the United States alone, a new novel is published every hour. Some ... extend their cultural reach by being turned into films." Beyond books, the strong skeleton of story can be discerned clearly in media including video games and scripted "reality" television. This is why libraries aren't likely to go away, Gottschall suggests. They may change in character; they may even transform into habitats for massive multiplayer online role-playing games. But they won't disappear.

The medium of story is changing, but not its essence. Our inborn thirst for narrative means that story - its power, purpose and relevance - will endure as long as the human animal does.