Spermatic. There’s a word you don’t come across much anymore. Not only does it sound fusty and arcane, as if it had been extracted from the nether regions of a moldy physiology handbook, but it seems fatally tainted with political incorrectness. Only the rash or the drunken would dare launch the word into a conversation at a cocktail party.

It wasn’t always a pariah. In an essay published in The Atlantic Monthly in 1858, the poet and philosopher Ralph Waldo Emerson chose the adjective to describe the experience of reading: “I find certain books vital and spermatic, not leaving the reader what he was.” For Emerson, the best books — the “true ones” — “take rank in our life with parents and lovers and passionate experiences, so medicinal, so stringent, so revolutionary, so authoritative.” Books are not only alive; they give life, or at least give it a new twist.

Emerson drew a distinction between his idea of reading and one expressed a few centuries earlier by the French essayist Michel de Montaigne, who termed books “a languid pleasure.” What was medicine for Emerson was intoxicant to Montaigne. If my own experience is any guide, both men had it right. Like Montaigne, I’ve spent many happy hours under the spell of books, enchanted by the beauty or wit of the prose, the plot’s intrigue, the elegance of the argument. But there have also been times when, like Emerson, I’ve felt a book’s metamorphic force, when reading becomes a means not just of diversion or enlightenment but of regeneration. One closes such a book a different person from the one who opened it. In his poem “Two Tramps in Mud Time,” Robert Frost, one of Emerson’s many heirs, wrote of the rare moments in life when “love and need are one, / And the work is play for mortal stakes.” That seems to me a good description of reading at its most vital and spermatic.

My life has been punctuated by books. The Lord of the Rings and The Martian Chronicles added mystery to my boyhood, opening frontiers to wander in and marvel at far beyond my suburban surroundings. The tumult of my teenage years was fueled by rock records, but it was put into perspective by books as various as Kerouac’s On the Road and Hemingway’s In Our Time, Philip Roth’s Portnoy’s Complaint and Joseph Heller’s Something Happened. During my twenties, a succession of thin volumes of verse—Frost’s A Witness Tree, Philip Larkin’s Whitsun Weddings, Seamus Heaney’s North—were the wedges I used to pry open new ways of seeing and feeling. The list goes on, decade by decade: Hardy’s Return of the Native, Joyce’s Ulysses, Cormac McCarthy’s Blood Meridian, Tom Wolfe’s The Electric Kool-Aid Acid Test, Denis Johnson’s Jesus’ Son, and, recently, the wondrous voyage that is Patrick O’Brian’s Aubrey-Maturin series. Who would I be without those books? Someone else.

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Psychologists and neurobiologists have begun studying what goes on in our minds as we read literature, and what they’re discovering lends scientific weight to Emerson’s observation. One of the trailblazers in this field is Keith Oatley, a cognitive psychologist at the University of Toronto and the author of several novels, including the acclaimed The Case of Emily V. “For a long time,” Oatley told the Canadian magazine Quill & Quire, “we’ve been talking about the benefits of reading with respect to vocabulary, literacy, and these such things. We’re now beginning to see that there’s a much broader impact.” A work of literature, particularly narrative literature, takes hold of the brain in curious and powerful ways. In his 2011 book Such Stuff as Dreams: The Psychology of Fiction, Oatley explained that “we don’t just respond to fiction (as might be implied by the idea of reader response), or receive it (as might be implied by reception studies), or appreciate it (as in art appreciation), or seek its correct interpretation (as seems sometimes to be suggested by the New Critics). We create our own version of the piece of fiction, our own dream, our own enactment.” Making sense of what transpires in a book’s imagined reality appears to depend on “making a version of the action ourselves, inwardly.”

One intriguing study, conducted a few years ago by research psychologists at Washington University in St. Louis, illuminates Oatley’s point. The scholars used brain scans to examine the cellular activity that occurs inside people’s heads as they read stories. They found that “readers mentally simulate each new situation encountered in a narrative.” The groups of nerve cells, or neurons, activated in readers’  brains “closely mirror those involved when [they] perform, imagine, or observe similar real-world activities.” When, for example, a character in a story puts a pencil down on a desk, the neurons that control muscle movements fire in a reader’s brain. When a character goes through a door to enter a room, electrical charges begin to flow through the areas in a reader’s brain that are involved in spatial representation and navigation.

More than mere replication is going on. The reader’s brain is not just a mirror. The actions and sensations portrayed in a story, the researchers wrote, are woven together with “with personal knowledge from [each reader’s] past experiences.” Every reader of a book creates, in Oatley’s terms, his own dream of the work — and he inhabits that dream as if it were an actual place.

When we open a book, it seems that we really do enter, so far as our brains are concerned, a new world — one conjured not just out of the author’s words but out of our own memories and desires — and it is our cognitive immersion in that world that gives reading its emotional force. Psychologists draw a distinction between two kinds of emotions that can be inspired by a work of art. There are the “aesthetic emotions” that we feel when we view art from a distance, as a spectator: a sense of beauty or of wonder, for instance, or a feeling of awe at the artist’s craft or the work’s unity. These are the emotions that Montaigne likely had in mind when he spoke of reading’s languid pleasure. And then there are the “narrative emotions” we experience when, through the sympathetic actions of our nervous system, we become part of a story, when the distance between the attendee and the attended evaporates. These are the emotions Emerson may have had in mind when he described the spermatic, life-giving force of a “true book.”

Readers routinely speak of how books have changed them. A 1999 survey of people who read for pleasure found that nearly two-thirds believe they have been transformed in lasting ways by reading. This is no fancy. Experiencing strong emotions has been shown to cause alterations in brain functions, and that appears to hold true for the feelings stirred by stories. “The emotions evoked by literary fiction,” Oatley reported in a 2010 paper written with psychologist Raymond Mar of York University in Toronto, “have an influence on our cognitive processing after the reading experience has ended.” Although the full extent of that influence has yet to be measured in a laboratory, and may never be, it seems likely that the unusual length of time that we spend immersed in the world of a book would result in particularly strong emotional responses and, in turn, cognitive changes. These effects would be further amplified, argued Oatley and Mar, by the remarkably “deep simulation of experience that accompanies our engagement with literary narratives.”

A 2009 experiment conducted by Oatley and three colleagues suggests that the emotions stirred by literature can even alter, in subtle but real ways, people’s personalities. The researchers recruited 166 university students and gave them a standard personality test measuring such traits as extraversion, conscientiousness, and agreeableness. One group of the subjects read the Chekhov short story “The Lady with the Toy Dog,” while a control group read a synopsis of the story’s events, stripped of its literary qualities. Both groups then took the personality test again. The results revealed that the people “who read the short story experienced significantly greater change in personality than the control group,” and the effect appeared to be tied to the strong emotional response that the story provoked. What was really interesting, Oatley says, is that the readers “all changed in somewhat different ways.” A book is rewritten in the mind of every reader, and the book rewrites each reader’s mind in a unique way, too.

What is it about literary reading that gives it such sway over how we think and feel and maybe even who we are? Norman Holland, a scholar at the McKnight Brain Institute at the University of Florida, has been studying literature’s psychological effects for many years, and he offers a provocative answer to that question. Although our emotional and intellectual responses to events in literature mirror, at a neuronal level, the responses we would feel if we actually experienced those events, the mind we read with, Holland argues in his book Literature and the Brain, is a very different mind from the one we use to navigate the real world. In our day-to-day routines, we are always trying to manipulate or otherwise act on our surroundings, whether it’s by turning a car’s steering wheel or frying an egg or tapping a button on a smartphone. But when we open a book, our expectations and attitudes change. Because we understand that “we cannot or will not change the work of art by our actions,” we are relieved of our desire to exert an influence over objects and people and hence can “disengage our [cognitive] systems for initiating actions.” That frees us to become absorbed in the imaginary world of the literary work. We read the author’s words with “poetic faith,” to borrow a phrase that the psychologically astute Samuel Coleridge used two centuries ago.

“We gain a special trance-like state of mind in which we become unaware of our bodies and our environment,” explains Holland. “We are ‘transported.’” It is only when we leave behind the incessant busyness of our lives in society that we open ourselves to literature’s regenerative power. That doesn’t mean that reading is anti-social. The central subject of literature is society, and when we lose ourselves in a book we often receive an education in the subtleties and vagaries of human relations. Several studies have shown that reading tends to make us at least a little more empathetic, a little more alert to the inner lives of others. A series of experiments by researchers at the New School for Social Research, reported in Science in 2013, showed that reading literary fiction can strengthen a person’s “theory of mind,” which is what psychologists call the ability to understand what other people are thinking and feeling. “Fiction is not just a simulator of a social experience,” one of the researchers, David Comer Kidd, told The Guardian newspaper; “it is a social experience.” The reader withdraws in order to connect more deeply.

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The discoveries about literature’s psychological and cognitive effects won’t come as much of a surprise to readers. The research will serve mainly to confirm their intuitions. But the science is important nonetheless. It arrives at a crucial moment in the history of reading, and perhaps of literature. Not only has a new medium for reading — the computer screen — become popular as an alternative to the printed page; the value of reading as an end in itself is coming in for questioning. A strangely distorted view of reading has gained currency in some quarters. A group of social-networking enthusiasts has taken to referring to the book, in its traditional form, as a “passive” medium, lacking the “interactivity” of websites, apps, and video games. Because a page of paper can’t accommodate links, Like buttons, search boxes, comment forms, and all the other spurs to online activity we’ve become accustomed to, the reasoning goes, the readers of books must be mere consumers of content, inert caricatures of Montaigne’s languid reader. Jeff Jarvis, a media consultant who teaches journalism at the City University of New York, gave voice to this way of thinking in a post on his blog. Claiming that printed pages “create, at best, a one-way relationship with a reader,” he concluded that, in the internet era, “the book is an outdated means of communicating information.” He declared that “print is where words go to die.”

Anyone who would reduce a book to a “means of communicating information,” as if it were a canister for shuttling facts and figures among bureaucrats, is probably not the best guide to the possibilities of literary experience. But when foolish ideas get into progress’s slipstream, they can travel far. Some makers of e-reading devices and related software applications are embracing the notion that literature could do with a digital upgrade, that the experience of reading would improve if it were less solitary and more “social.” Books “often live a vibrant life offline,” grants a Google executive, but they will be able to “live an even more exciting life online.” Such views reflect more than just technological enthusiasm. Something deeper is going on. Society is growing ever more skeptical of the value of solitude. The status quo treats with suspicion  even the briefest of withdrawals into inactivity and apparent purposelessness. We see it in the redefinition of receptive states of mind as passive states of mind. We see it in an education system that seems uncomfortable with any “outcome” unsuited to formal measurement. We see it in the self-contempt of the humanities. We see it in the glorification of the collaborative team and the devaluation of the self-reliant individual. We see it in the general desire to make all experience interactive and transactional.

In a 2003 lecture, Andrew Louth, a theology professor at the University of Durham in England, drew a distinction between “the free arts” and “the servile arts.” The servile arts, he said, are those “to which a man is bound if he has in mind a limited task.” They are the arts of production and consumption, of getting stuff done, to which most of us devote most of our waking hours. The free arts, among which Louth included reading as well as meditation, contemplation, and prayer, are those characterized, in one way or another, by “the search for knowledge for its own sake.” They are aimed at no useful or measurable end, and by engaging in them we slip, if only briefly, the bonds of the practical. We open ourselves to aesthetic and spiritual possibilities. We embrace and inhabit an ideal that was once central to the idea of culture itself: “that there is more to human life than a productive, well-run society.” This ideal, Louth said, is now “under serious threat, and with it our notion of civilization.”

The computer exists to aid in transactions. It is never not processing. As society becomes more narrowly focused on the servile arts, the computer naturally becomes more central to its operation. The relationship becomes symbiotic, and the free arts, which are antithetical to the transactional, are pushed to the margin. Then again, it might be argued that the margin has always been the best place to relax with a book. As Norman Holland suggests, the deepest kinds of reading entail a dampening of our urge to act. They require a withdrawal from quotidian busyness and so are marginal to society almost by definition. Montaigne’s and Emerson’s views may actually be more in concert than in conflict. It may be that readers have to enter a state of languid pleasure, a dream, before they can experience the full spermatic vitality of a book. Far from being a sign of passivity, the reader’s outward repose signals the most profound kind of inner activity, the kind that goes unregistered by society’s sensors.

An earlier version of this essay appeared in the book Stop What You’re Doing and Read This!