How We Learn

What if almost everything you’ve been told about learning—about concentration, discipline, and sticking to a single study routine—was wrong? In How We Learn, science journalist Benedict Carey turns the traditional image of the earnest, hyper-focused student on its head. He argues that true learning doesn’t come from brute effort or memorization but from working with your brain’s natural rhythms—its quirks, distractions, and periodic forgetfulness. Learning, Carey insists, is not a straight climb up a mountain of knowledge. It’s more like a wandering journey through a forest where getting lost, taking detours, and even breaking the rules can accelerate understanding.

Why Traditional Study Myths Fail

Carey begins with his own transformation—from the classic grind who believed hard work and total focus were the only pathways to mastery, to a more relaxed, curious student who learned better once he loosened his grip. He uses this story to highlight how common habits—long study marathons at the same desk, late-night cramming, endless repetition—actually limit comprehension. These habits ignore how the brain really operates: a dynamic, pattern-seeking organ that learns best when its environment, timing, and focus are varied. Many of us try to force the brain into a kind of mechanical discipline, Carey writes, when in fact learning is more organic, more eccentric, and more playful than we realize.

The Brain as a Story-Making Machine

Part of the reason these myths persist is that we misunderstand memory. Carey, drawing on neuroscientists such as Michael Gazzaniga and Brenda Milner, shows that memory isn’t a filing cabinet but a living network constantly rewriting itself. The brain, he says, is a “story maker”—endlessly constructing narratives to make sense of what we experience. Forgetting, revising, and reconstructing are integral to how it strengthens skills and knowledge. That’s why distractions or breaks often help rather than hurt: they allow the subconscious to connect fragments and reinforce meaning, something pure repetition can’t do.

A Map of Modern Learning Science

Carey organizes the book like a scientific expedition through modern cognitive psychology. He begins with basic brain biology—the partnership between the hippocampus, neocortex, and neural “storytelling” systems that create, lose, and reforge memories. Then he explores how scientific discoveries about memory timing, context, and testing can be reused as practical study tools. Each of the four main parts of the book—Basic Theory, Retention, Problem Solving, and Tapping the Subconscious—introduces a technique that flies in the face of common wisdom but boosts long-term learning. For example, varying where you study (context), spacing out sessions, testing yourself before you’re ready, quitting right before success, and even sleeping strategically all improve performance. Later chapters expand to creativity, incubation, and how rest and play refine insight.

The Big Takeaway: Learning as a Way of Life

Carey’s core argument is both scientific and humanistic: learning is not about raw intellect or effort but about managing attention and forgetfulness wisely. When we integrate learning into daily life—when we absorb information amid the noise, schedules, and randomness of our days—we begin to use the brain as it evolved to work. This makes learning feel less like drudgery and more like living. He compares this to the hunter’s instincts of our ancestors: the brain is a forager, designed to explore widely, take cues from the environment, and make sense of the world through trial, error, and surprise. The more we mimic that natural curiosity, the deeper our knowledge goes.

In the pages ahead, you’ll learn why forgetting is a friend, not a failure; why distractions and variation enrich memory; how testing yourself improves understanding; why stopping before you’re finished can boost creativity; and how sleep cements ideas. Carey’s message is liberating: we don’t need to fight our mental rhythms to learn—we need to work with them. That shift turns learning from a disciplined grind into an adaptable, lifelong habit, shaped by curiosity, rest, and even a little chaos.

To understand how learning really happens, Carey starts with the brain’s inner drama. Forget the heroic image of a perfectly efficient computer. The human brain, he writes, is closer to a film crew shooting a documentary — a noisy team of specialists constantly editing and retelling your life story. Neurons fire in networks of meaning, linking sights, sounds, feelings, and places into complex recordings that are rewritten every time you remember them.

How Memory Works: From H.M. to the Story Maker

Carey describes the famous case of Henry Molaison (known as H.M.), whose surgery for epilepsy destroyed his hippocampus. Molaison could never form new memories, though he could still learn physical skills—like tracing a star in a mirror. This discovery revealed two memory systems: one conscious, one subconscious. Memory doesn’t live in a single spot but across regions like the hippocampus (where experiences start) and the neocortex (where long-term meaning resides). When these systems work together, they form the foundation for what Carey calls the “story maker”—the part of your brain that weaves sensory data into coherent narratives.

The Interpreter and the Illusion of Coherence

Building on Michael Gazzaniga’s split-brain research, Carey explains that one hemisphere of your brain, usually the left, acts as an “interpreter,” constantly making up explanations to link scattered pieces of information. This process gives you the illusion of unity and certainty, even though your mind is improvising the story. Understanding that illusion helps explain why memory changes over time and why rethinking material—rather than memorizing it—strengthens understanding. The act of remembering, Carey emphasizes, changes the memory each time, layering new context and meaning onto the old.

The Brain You Can Work With

If the brain is an “eccentric learning engine,” its quirks—distraction, dreams, and the impulse to rewrite—are not glitches. They’re survival features. Our ancestors learned by wandering, noticing patterns, and updating their internal maps. Today, when you allow your brain to revisit information in different places or mental states, you’re leveraging the same evolutionary system. That’s why Carey calls for studying in varied contexts: each change provides a new angle for the brain’s story maker to connect details, enriching recall and creativity. Rather than suppress its irregular rhythm, you should engage it—because the brain’s disorderly tendencies are also the source of insight.

Most people see forgetting as a mental flaw. Carey flips that belief upside down. He shows, through psychological experiments, that forgetting isn’t failure—it’s how memory strengthens. The UCLA researchers Robert and Elizabeth Bjork call this the New Theory of Disuse. Every memory has two kinds of strength: storage strength (how well it’s learned) and retrieval strength (how accessible it is right now). Forgetting simply weakens retrieval, not storage. When we recall something after partially forgetting it, both strengths increase more than they did before.

Desirable Difficulty

This counterintuitive idea explains why struggling to remember—like puzzling over a word or reworking a problem—deepens understanding. Carey calls this desirable difficulty: the harder the retrieval, the bigger the gain. When you force your brain to climb back to an idea instead of being spoon-fed it, you rebuild and reinforce the neural path. Learning therefore depends on timed forgetting cycles—studying just as material begins to fade. This pattern mirrors how muscles strengthen through stress and recovery.

Ebbinghaus, Ballard, and the Curve of Memory

Carey revives two pioneers of memory science: Hermann Ebbinghaus, who charted the famous “forgetting curve” in the 1880s using nonsense syllables, and Philip Ballard, who found that children sometimes recalled poems better days later—without study. This phenomenon of “reminiscence” shows that the mind keeps working offstage. Much of what seems like fading is actually reorganization. As Carey notes, the mind is performing silent triage, deciding which memories to strengthen and which to filter out as clutter.

Practical Takeaway

So how do you use the power of forgetting? By spacing your study, revisiting material just before it vanishes from mind. Cramming burns retrieval strength hot and fast; spacing lets it fade enough to reignite powerfully. That’s why reviewing old material after a gap leads to longer retention—sometimes double. Once you see forgetting as a friend, you learn to design your schedule around it. As Carey puts it, “Without a little forgetting, you get no benefit from further study.”

The idea of a single, silent study space—a “perfect desk”—has become a cornerstone of education culture. Carey dismantles it. Borrowing from psychologist Steven Smith’s experiments and a legendary Scottish scuba-diving study, he shows that changing context actually improves recall. Memory links information to environmental cues: sounds, colors, moods, smells. When those cues vary, your brain builds multiple paths back to the material. Learn the same idea in different settings, and it becomes more portable.

The Power of Context Change

In Godden and Baddeley’s underwater experiment, divers remembered lists best when tested in the same environment where they’d studied—underwater or on land. But rather than sticking to one environment, Carey shows the smarter move is to use many. Psychologists later found that switching study spaces (like alternating between a quiet room and a noisy café) improved recall by about 40%. New surroundings generate new associations—each set of cues becomes another key that can unlock memory later, even during stress tests.

Mental States and Internal Context

Carey also explores “state-dependent learning”—the surprising discovery that we recall information best when our internal chemistry or mood matches the state we were in while learning. One experiment at the National Institute of Mental Health used marijuana: students who studied while high recalled better when tested high again than sober. Mood, caffeine level, even mild intoxication—all shape cue networks. You don’t need drugs, of course; changes in time of day or energy level create similar internal variety without the side effects.

Variation as a Strategy, Not a Distraction

Even small shifts—a new playlist, a different seating position—refresh attention and expand memory cues. “We’re better off varying what we can,” Carey writes, echoing researcher Daniel Willingham. To see this principle in action, he recounts Steven Smith’s experiment where students studying word lists in rooms with different décor and music recalled far more words than those who stayed put. The lesson? Don’t idolize focus. Stability comforts the mind but doesn’t challenge it to connect ideas flexibly. Change environments, and you teach the brain to retrieve knowledge anywhere, not just at your desk.

If forgetting tunes memory, then spacing is how we conduct that symphony. The spacing effect—the discovery that breaking up study time increases retention—has been proven since the 1880s, yet ignored by most schools. Carey reintroduces it through the story of Harry Bahrick’s family experiment: four relatives studying foreign vocabulary for years under different review intervals. The group that reviewed words once every two months remembered 50% more after five years than those who practiced weekly. The key wasn’t more time—it was distributed time.

Why Spacing Works

Spacing forces retrieval under slight pressure. Each interval allows partial forgetting, so every review session is a mini test. Psychologically, it re-engages “desirable difficulty.” Biologically, it strengthens neural networks through repeated reconsolidation. Carey likens it to watering plants: frequent, light doses keep roots deep; a single flood runs off. He also profiles Piotr Wozniak, the Polish scientist who created SuperMemo, a software that calculates optimal intervals for review. Its algorithm is simple: review material right before you’re about to forget it. That’s the digital version of what your memory naturally craves.

Applying the Timing Equation

With psychologist Harold Pashler, Melody Wiseheart discovered that the ideal gap depends on when you’ll need the knowledge. If your exam is in a week, study today and review in one or two days. If it’s in six months, review after about three weeks. The further away the exam, the longer the spacing interval should be, proportionally shorter to total prep time. Carey calls spacing “a free miracle”—a technique that doubles retention without extra effort. It transforms ordinary study hours into multipliers of long-term memory.

More Learning, Less Grinding

Spacing demonstrates Carey’s larger point: better learning doesn’t require more willpower, just better rhythm. As William James wrote, “Cramming seeks to stamp things in by intense application … but the same thing recurring on different days, in different contexts, gets wrought into mental structure.” Thinking of study as rhythmic practice—more like exercise or music—turns your calendar into a brain-training schedule. Mastery, Carey reminds us, depends less on intensity than on timing.

Few students see tests as allies. Carey shows they should. Testing isn’t just assessment—it’s active learning. Each quiz forces retrieval, deepening both storage and recall. The effect was discovered over a century ago by Arthur Gates and Herbert Spitzer, who noticed that reciting from memory reinforced learning more than rereading. Spitzer’s massive 1939 study with 3,600 Iowa students proved that pop quizzes soon after studying locked information in far better than delayed ones. Testing, in short, is studying; it launches the brain’s own feedback loop.

The Power of Retrieval Practice

Modern versions of this insight come from Henry Roediger and Jeffrey Karpicke’s research at Washington University. They showed that students who spent half their time testing themselves on readings remembered up to 50% more a week later than those who only restudied. Self-exams work because they reveal gaps—the antidote to the “fluency illusion,” that deceptive ease we feel when material looks familiar. When you teach or explain what you’ve learned, you also trigger the testing effect. Carey’s takeaway is clear: don’t just read—recite, quiz, and pretend to teach.

Pretesting and Productive Failure

Even failed tests train perception. The Bjorks found that answering impossible questions before learning material—the “pretest,” even when answered wrong—increases later comprehension. Guessing primes the brain to notice correct patterns when they appear. In one UCLA study, students who guessed answers on future lecture topics scored 10% higher on finals than those who hadn’t. Failures widen mental search parameters. As Carey notes, “Pretend you’re an expert and give a commentary.” Faking mastery is how real mastery begins.

Reclaiming the Exam

Testing has long been stigmatized as stressful ranking. Carey reframes it as self-exploration: a mirror, not a judgment. Every quiz gives feedback your brain uses to recalibrate its narrative; every recall attempt strengthens knowledge. The right mindset turns exams from obstacles into milestones of understanding. Practice tests before you’re ready, he suggests, because learning happens not when you know the answer but when you realize you don’t.

Have you ever solved a tough problem while showering or realized an idea hours after giving up? Carey explores this phenomenon—scientists call it incubation. The unconscious mind keeps working after your conscious one stalls. When you set a problem aside, your brain reorganizes data and relaxes mental ‘fixations’ that trap you in dead ends. In one classic 1931 experiment, psychologist Norman Maier asked people to tie two hanging ropes together. Most failed until he casually brushed one rope to set it swinging; soon, nearly everyone “saw” the solution—to use the rope as a pendulum. They believed it was their own idea. Incubation had worked behind the scenes.

Breaking Fixedness Through Distraction

Carey connects Maier’s work to Karl Duncker’s Candle Problem, where the trick was to unfix the idea that a box is only a container, not also a platform. These experiments show that being stuck isn’t useless—it’s evidence the brain is recombining old material. Taking a walk, checking messages, or switching tasks allows selective forgetting, letting irrelevant assumptions fade. Studies by Steven Smith and Steven Blankenship found that even a five-minute break of unrelated reading doubled problem-solving for stuck participants. Minds unfocused are often minds freeing themselves.

The Upside of Modern Distraction

In a world buzzing with digital diversions, Carey offers a refreshing verdict: minor distractions can help. When you’re motivated but blocked—on a math problem, a code bug, or a creative project—jumping to a playful, absorbing side activity primes incubation. This aligns with findings by Ut Na Sio and Thomas Ormerod, whose meta-analysis confirmed that incubation periods, even just 20 minutes, consistently enhance creative problem-solving. Controlled wandering replenishes insight. The trick is to disengage deliberately, not to give up.

Quitting gets a bad rap. But Carey shows that stopping before you’re ready—especially on complex, creative projects—can supercharge ideas. He calls this extended incubation percolation. Drawing on Bluma Zeigarnik’s 1927 research, he explains that uncompleted tasks haunt our minds more than finished ones, keeping subconscious attention active. This Zeigarnik effect is why cliffhangers hook audiences—and why leaving work midstream can fuel discovery overnight. The mind keeps “checking back in,” looking for closure, even while you’re doing something else.

Interrupted Work Sparks Vigilance

Carey pairs Zeigarnik’s finding with Henk Aarts’s Dutch experiment in which thirsty participants remembered drink-related objects twice as often as others. Unmet needs tune perception. Similarly, when you interrupt writing a paper, painting, or solving an equation, your goal remains “unfulfilled,” priming the environment for clues. The world becomes your research assistant. As novelist Eudora Welty put it, “Once you’re into a story, everything seems to apply.” Percolation isn’t magic—it’s motivation extended by interruption.

How to Practice Productive Procrastination

Carey introduces the idea of deliberate self-interruption: start a long project early, then step away when you hit a good but incomplete stopping point. During downtime, your mind forages for ideas while your attention rests. Ronda Dively’s writing students who worked gradually on one essay all semester produced more confident, original arguments than peers juggling multiple quick ones. They had been percolating. This technique reframes procrastination as participation by the subconscious. To “quit before you’re ahead” is to ensure your inner processor keeps running.

Practicing one skill over and over feels satisfying—but it’s an illusion of mastery. Carey calls this blocked practice and contrasts it with interleaving, or mixing related tasks. Studies show interleaving strengthens comprehension and flexibility, even when progress feels slower. In a 1978 experiment, Robert Kerr and Bernard Booth found that children who practiced throwing beanbags at two different distances outperformed those who practiced only at one, even when tested at the unpracticed distance. Variety built adaptability.

From the Gym to the Classroom

Richard Schmidt and Robert Bjork later unified this idea across motor and verbal learning. Whether badminton skills or algebra, alternating between techniques strengthens discrimination—the ability to tell tasks apart and match problems with the right solutions. Doug Rohrer’s math students who mixed geometry and algebra in homework (instead of isolating topics) scored nearly twice as high on cumulative tests. Interleaving makes you choose strategies consciously, sharpening pattern recognition and long-term mastery.

Why Mixing Feels Hard—and Works Anyway

Mixed practice feels confusing because it removes the safety net of repetition. Yet that confusion produces “reset moments,” forcing your brain to re-engage with meaning rather than routine action. Nate Kornell and Bjork’s art-study experiment, where students learned painters’ styles, showed that those who saw mixed paintings recognized unseen works 15% more accurately. Mixing boosted “category awareness”—an intuitive sense of what makes each style distinct. Carey concludes that interleaving mirrors real life: no test, performance, or problem ever comes in neat blocks. Training for variability prepares your brain for the unexpected.

Some of the fastest learning, Carey reveals, happens beneath awareness—what psychologist Eleanor Gibson called perceptual learning. You don’t consciously memorize subtle distinctions; you internalize them through exposure and feedback. Gibson’s experiments showed that both children and adults improved at telling similar doodles apart without ever realizing how. The same unconscious skill lets a baseball player anticipate a curveball or a radiologist spot an anomaly. Experts, Carey says, literally see differently.

Harnessing the Subconscious with PLMs

UCLA researcher Philip Kellman built on Gibson’s ideas with Perceptual Learning Modules—computer programs that rapidly train intuition. In one, beginners learned to read airplane instrument panels as accurately as veteran pilots after an hour of trial-and-feedback practice. Similar modules teach surgeons to recognize anatomical patterns, dermatologists to identify skin diseases, and students to match chemical bonds to graphs. Quick, repetitive discrimination builds perceptual intuition before conscious reasoning catches up. It’s like tuning an internal radar.

Why “Feel” Matters

Traditional education worships explicit knowledge—rules, formulas, instruction. Perceptual learning exposes its hidden complement: implicit know-how. By training the senses to detect meaningful features quickly, you gain fluency that later feeds analysis. This aligns with research on “chunking” in chess and music—the way experts group patterns automatically. Carey even demonstrates it by building his own art-history quiz module to recognize Impressionism or Cubism. Knowledge grows in two directions at once: upward in logic and downward in perception.

Learning doesn’t end when you close your eyes. Carey calls sleep your brain’s “night shift” — a period when memories consolidate, patterns form, and insights emerge. Drawing on pioneers Eugene Aserinsky and Nathaniel Kleitman, who discovered REM sleep in the 1950s, Carey shows that the sleeping brain is astonishingly active, cycling through stages that each handle a different kind of learning. REM (rapid eye movement) aids creativity and emotional regulation; deep slow-wave stages store hard facts; light sleep (Stage 2) strengthens muscle memory and physical skills. “Sleep,” he writes, “is learning with your eyes closed.”

Different Sleeps, Different Lessons

Studies by Carlyle Smith and Matthew Walker reveal that REM integrates ideas across experiences—a creative boost for problem-solving in math, art, and writing—while Stage 2 sleep helps motor coordination. That’s why practicing piano or basketball before bed can yield progress by morning. Meanwhile, early-night deep sleep secures storage of vocabulary, formulas, and historical facts. Timing matters: staying up late favors creative subjects; going to bed on time and rising early enhances factual recall.

Naps and the Evolutionary Role of Rest

Sara Mednick’s research shows an hour-long nap containing both REM and deep phases can replicate much of a full night’s learning boost. Evolutionarily, sleep likely evolved as cognitive maintenance: conserving energy and fine-tuning our memory maps from a day of foraging. Carey likens the process to a quiet janitorial crew—stripping emotional noise, storing the essentials, and running pattern-recognition cleanup. In this view, resting helps ideas gel; fatigue isn’t always failure to work hard but a cue your brain wants to process what it’s absorbed.