Jennifer Howard is a writer and editor living in Washington, D.C.

Rereading a favorite book is a pleasure and skill, one of many that neuroscientist Maryanne Wolf fears we might be losing in this era of screen immersion. In “Reader, Come Home,” she recounts an experiment she did on herself: She tried to reread Hermann Hesse’s “Magister Ludi,” a novel she calls “one of the most influential books of my earlier years.”


(Harper)

Her first attempt did not go well. “My grafted, spasmodic, online style, while appropriate for much of my day’s ordinary reading, had been transferred indiscriminately to all of my reading, rending my former immersion in more difficult texts less and less satisfying,” she writes. Wolf soon tried again, forcing herself to start with 20-minute intervals, and managed to recover her “former reading self.”

But the vexed question behind the experiment — “What would now become of the reader I had been?” — winds throughout “Reader, Come Home.”

Wolf wants to understand what’s happening to our reading brains at this historic juncture between the old ways and the new. A lifelong book lover who turned her fascination with reading into a career as a cognitive neuroscientist, she continues to explore how humans learned to do such an astonishing thing as read in the first place.

Unlike sight and vision, as Wolf explained in her 2007 book, “Proust and the Squid,” the ability to read did not naturally evolve in humans. In her new book, she explores neuroplasticity — the amazing adaptability of our brains — and sketches out the “neurological circus” set in motion when a reader encounters words. She compares the many elements that reading sets in motion — vision, language, cognition — to the interactions among the performers in a three-ring circus. Wolf pushes the analogy harder than she needs to, but it does convey a sense of the neurological acrobatics the reading brain performs.

While neuroplasticity allowed humans to develop our “deep-reading circuit,” she explains, it also makes us vulnerable to constant streams of digital input. Clutching cellphones, scrolling through Instagram feeds, browsing websites all day, “we inhabit a world of distraction,” she writes.

One of many useful studies she cites found that the average person “consumes about 34 gigabytes across varied devices each day” — some 100,000 words’ worth of information. “Neither deep reading nor deep thinking can be enhanced by the aptly named ‘chopblock’ of time we are all experiencing, or by 34 gigabytes of anything per day,” Wolf argues. That’s true enough. I did a quick Google search — one of many digital detours I made as I wrote this review — and learned that “Middlemarch” contains about 316,000 words. Even in grad school I would have gotten very little out of the novel if I’d sped-read a third of it in 24 hours.

Wolf sees good reason to be alarmed, but “Reader, Come Home” veers away from despair over the life digital. This isn’t Nicholas G. Carr’s “The Shallows.” Wolf thinks (hopes) that a “biliterate brain” will evolve in young humans, who could learn to develop “distinctly different modes of reading from the outset.” She wants kids to become “expert code switchers,” able to move among media and from light reading to deep analysis and back again the way bilingual people switch between languages. We can hope.

Practical interventions will be necessary. Wolf recommends that early-childhood education continue to focus on print materials, with digital devices and lessons added over time. That includes how to code — essential for learning “that sequence matters,” whether it’s in a piece of writing or a piece of software — and how to handle time and distractions. (Sign me up.) Wolf calls for teachers to be better trained to use technology effectively in classrooms. Handing out iPads does not teach children how to read well on those devices or manage time on them. That requires active guidance from adults in the classroom and at home. She also wants more (and is involved in) research on how best to support learners, including people with dyslexia, who are not served by traditional approaches to literacy. It’s one of the brightest prospects sparked by the digital leap.

Digital technology can perpetuate inequalities as well as solve them. Not every kid grows up with books in the house; not every kid has access to a computer or the Internet either. And that’s only the first hurdle, as Wolf knows. “Merely having access does not ensure a child’s ability to use digital devices in positive ways,” she writes.

Even as it keeps one eye on the future, “Reader, Come Home” embodies some old-fashioned reading pleasures, with quotes from Italo Calvino, John Dunne, Toni Morrison, Marcel Proust, Elie Wiesel and other illustrious word-workers. It unfolds as a series of letters addressed to “Dear Reader” from “Your Author,” a call to remember that books come alive as exchanges between writers and readers.

That structure can make “Reader, Come Home” feel — in a corny but charming way — like a throwback to an era already gone, if it ever existed. Wolf offers a persuasive catalog of the cognitive and social good created by deep reading, but does not really acknowledge that the ability to read well has never been universal.

Still, she makes a sound case that if we don’t protect and cultivate what Dunne called the “quiet eye,” we could not only lose the pleasures of reading but also hasten the erosion of core democratic values, already under siege in American public and private life. She worries that we now lack the “cognitive patience” necessary to identify fake news and to entertain points of view very different from our own. That makes the ailing body politic more vulnerable to demagogues, white supremacists, Russian hackers and other poisonous influences. (Disclosure: Wolf quotes from a relevant essay I wrote, “Internet of Stings,” published in the Times Literary Supplement in 2016.)

In “Reader, Come Home,” Wolf spells out what needs protecting: the knowledge, analytical thinking, capacity for sustained attention and empathy for others inspired by immersion in books. She’s right that digital media doesn’t automatically doom deep reading and can even enhance it. She’s also correct that we have a lot to lose — all of us — if we don’t pay attention to what we’re doing with technology and what it’s doing to us.

READER,
COME HOME
The Reading Brain in a Digital World

By Maryanne Wolf

Harper. 260 pp. $24.99