Curious

When was the last time you felt truly curious—so absorbed by a question or idea that you lost track of time? Ian Leslie’s Curious: The Desire to Know and Why Your Future Depends on It begins with this kind of moment and asks why it matters. Leslie argues that curiosity is humanity’s fourth drive—a biological and cultural impulse as essential as hunger, sex, or safety. Yet, unlike those drives, it is fragile, socially shaped, and easily lost. The book is an exploration of what curiosity is, where it comes from, why it wanes, and how you can rekindle it.

Leslie contends that curiosity is not a simple trait but a complex, multifaceted force. It fuels discovery and progress, but it requires nurturing through knowledge, questioning, and a willingness to engage with difficulty. In the modern era—when information is abundant yet true curiosity is in decline—Leslie insists that understanding and cultivating curiosity is not a luxury but a necessity for both personal fulfillment and societal innovation.

The Fourth Drive

Humans share drives for survival with other species, but curiosity sets us apart. Using examples such as Kanzi the bonobo, who could learn symbols and communicate but never asked questions, Leslie illustrates that curiosity—particularly the urge to understand why—is uniquely human. It’s what pushes us to look beyond our immediate environment, to explore ideas, relationships, and possibilities that have no immediate practical benefit. This endless thirst for understanding built civilizations and continues to fuel invention.

However, Leslie warns that curiosity’s promise comes with risk. It’s inherently subversive—pulling us away from comfort and into unfamiliar territory. Historically, curiosity was seen as sinful or dangerous; Augustine condemned it as pride, while the Church feared its destabilizing power. Only during the Renaissance and Enlightenment did curiosity become respectable again, transforming from a moral hazard into a moral virtue. Today, Leslie argues, we are at another turning point: curiosity risks being smothered not by censorship, but by comfort and convenience.

Two Faces of Curiosity

Leslie distinguishes between two main types of curiosity first articulated by psychologist Daniel Berlyne: diversive curiosity and epistemic curiosity. Diversive curiosity is driven by novelty—it makes you check notifications, skim headlines, or click on endless links just for the thrill of the new. Epistemic curiosity, by contrast, is a deeper, more enduring desire to understand. It’s the curiosity that keeps Leonardo da Vinci up at night designing flying machines or pushes a scientist to investigate a stubborn anomaly. The first is about escaping boredom; the second is about embracing wonder. Both are essential, but as Leslie notes, our digital habits often amplify the shallow form at the expense of the deep one.

Why Curiosity Matters Now

Leslie situates curiosity at the center of three major discussions—education, technology, and mental well-being. Schools, he argues, often stifle curiosity by emphasizing standardized knowledge transfer rather than nurturing the urge to ask questions. Meanwhile, the Internet, though it provides access to all knowledge, can paradoxically dull our inquisitiveness by providing instant answers without exploration. And at a personal level, curiosity combats apathy and depression by expanding the boundaries of one’s attention and empathy. As one of Leslie’s central examples, British television producer John Lloyd—who created QI after a midlife crisis—illustrates how rediscovering curiosity can restore meaning when achievement and success no longer suffice.

Structure of the Book

Leslie divides the book into three parts that together form a journey from understanding curiosity’s origins to cultivating it in daily life. In Part One: How Curiosity Works, he examines the science and psychology of curiosity—how it begins in infants, how it is shaped by questions, and why it fades. Part Two: The Curiosity Divide explores societal forces that encourage or suppress curiosity, from class and culture to digital habits. Finally, Part Three: Staying Curious offers practical strategies through seven habits for keeping curiosity alive—from “staying foolish” to “questioning your teaspoons.”

A Humanizing Vision

Leslie’s thesis extends beyond individual development: curiosity builds empathy and culture. He draws a distinction between epistemic curiosity—about the world—and empathic curiosity—about other people’s emotions and experiences. Great literature and art thrive on the latter; novels from Robinson Crusoe to Uncle Tom’s Cabin cultivate empathy through imaginative curiosity. In both forms, curiosity connects us to something beyond ourselves, countering the narrowness and division of modern life.

“There is nothing more important or more strange than curiosity.” —John Lloyd, as quoted in the book

Curiosity, Leslie concludes, is the human instinct that makes progress, empathy, and joy possible. But it is also imperiled—by distraction, complacency, and systems that value answers more than questions. His mission is both philosophical and practical: to explain how curiosity operates and to help you build a life, a career, and a culture sustained by genuine wonder. If you care about learning, creativity, or simply being more alive to the world, this book invites you to rediscover your own desire to know.

Curiosity begins early—long before we can put our questions into words. Leslie starts with the world of babies at London’s Babylab, where psychologists observe infants exploring toys, sounds, and faces. Researchers Teodora Gliga and Katarina Begus discovered that an infant’s curiosity depends not only on her intelligence but also on how adults respond. When parents react warmly and answer a baby’s gestures or babbles, curiosity flourishes. When adults ignore or dismiss them, curiosity fades. From the very beginning, Leslie reminds us, curiosity is a collaboration.

From Pointing to Questioning

Pointing, Gliga found, is an early form of inquiry. When a child points to an object, she’s not just asking for it—she’s asking about it. If the parent names or explains the object, the baby learns that questions lead to knowledge. If the adult merely hands it over, she learns that questions only get things. This dynamic lays the foundation for either a lifelong thirst for learning or an incurious dependence on surface rewards. Leslie draws a straight line from those early interactions to the kind of adults we become: ones who wonder or ones who scroll.

The Rise—and Decline—of Questions

By age three, most children have entered what psychologists call “the question phase.” They ask thousands of questions—most famously “why?”—driving parents to exhaustion. Psychologist Michelle Chouinard found that preschoolers ask roughly 100 questions an hour, two-thirds of which are genuine requests for knowledge. They’re not just repeating words; they’re performing small thought experiments on reality. Yet by the time we reach adulthood, Leslie laments, we’ve fallen tragically silent. The world trains us to stop asking why.

Drawing from philosopher Paul Harris, Leslie explains that question asking requires three cognitive feats: recognizing your ignorance, imagining alternatives, and trusting others as sources of truth. These skills must be taught and reinforced. Without them, curiosity turns brittle; we stop admitting what we don’t know or fear asking questions that might reveal ignorance. That is why classrooms and workplaces that prize right answers over inquiry often breed passive, incurious minds.

Childhood curiosity thrives when adults model it, reward it, and participate in it. It dies when they dismiss questions as interruptions rather than opportunities.

Curiosity as Social Energy

Curiosity is not just intellectual; it’s social. Infants learn fastest when they sense interest from others because curiosity is contagious. The social shaping of curiosity continues throughout life. In one of Leslie’s examples, psychologist Dan Rothstein worked with struggling parents in Massachusetts who didn’t know how to ask questions of school officials. Once he taught them the skill of crafting open-ended queries, their sense of empowerment—and their children’s engagement—grew dramatically. Questioning, Leslie says, is not a talent; it’s a trainable human superpower.

From Diversive to Epistemic Curiosity

Leslie connects developmental science to cognitive theory. He highlights George Loewenstein’s information gap theory, which defines curiosity as the desire to close the gap between what we know and what we want to know. It is strongest when the gap feels close enough to be reachable but not so vast that we despair. Psychologist Daniel Berlyne’s earlier research supports this: we’re most engrossed when a subject is just beyond our current understanding. Curiosity, then, is a dynamic balance between confidence and uncertainty.

Fear: The Enemy of Curiosity

Where curiosity falters, fear often hovers nearby. Leslie describes how anxiety—whether in a child’s home, a rigid school, or an oppressive culture—can suffocate the urge to explore. Psychologist Todd Kashdan put it simply: “Anxiety and curiosity are opposing systems.” The safest environments for curiosity are not careless ones, but secure ones: when you trust that failure won’t lead to ridicule or punishment, curiosity has room to play. This is why a loving parent or open-minded teacher may be the most powerful curiosity catalyst a child ever meets.

By the end of this section, Leslie reframes curiosity as less of a trait and more of a temperature. It warms in supportive, stimulating contexts and cools in fearful or apathetic ones. Understanding how curiosity works means learning not just how to spark it, but how to keep its flame alive in a world that constantly threatens to blow it out.

In one of the most sweeping chapters, Leslie tells the story of how humanity’s attitude toward curiosity has shifted across history—from sinful indulgence to noble virtue. He traces how thinkers like Augustine condemned curiosity as intellectual pride, while later figures like Francis Bacon and the Enlightenment philosophers reclaimed it as the engine of progress. Understanding this transformation helps you see why curiosity remains conflicted today: part vice, part virtue, caught between the thrill of discovery and the fear of disorder.

From Sin to Science

For centuries, curiosity was dangerous. Augustine warned Christians against seeking knowledge for its own sake; it distracted from contemplation of God. This suspicion, Leslie explains, persisted throughout the Middle Ages. It wasn’t until the Renaissance—through figures like Leonardo da Vinci and Galileo—that curiosity was rehabilitated as a divine celebration of creation, not a rebellion against it. When Francis Bacon declared that investigating nature was “an innocent and kindly sport,” curiosity became a sign of humanity’s greatness, not its fall.

The Enlightenment’s Explosion of Questions

Printing and the Protestant Reformation hurled curiosity into the public sphere. Books, pamphlets, and newspapers transformed questioning from an elite privilege to a civic habit. Leslie cites historian Roy Porter’s estimate that between 1660 and 1800, over 200 million books and pamphlets circulated in England alone. Coffeehouses became hubs of debate and serendipity. Curiosity leapt from cloisters to crowds, propelling the scientific and industrial revolutions. Benjamin Franklin, the prototypical “thinkerer,” turned wonder into invention, proving that curiosity could power economies as well as intellects.

From Empathic Curiosity to Digital Apathy

Leslie expands curiosity’s meaning beyond science, celebrating the rise of empathic curiosity—the moral imagination cultivated through literature and art. Novels like Pamela or Uncle Tom’s Cabin encouraged readers to inhabit the minds of others, deepening social understanding and fueling democratic ideals. Yet this empathic impulse, he cautions, is waning in a culture that prizes instant reaction over sustained engagement. Where the Enlightenment’s curiosity expanded minds, our current flood of information risks narrowing them.

The Age of Answers

By contrasting the Enlightenment’s curiosity with our own, Leslie marks the arrival of what he calls the “Age of Answers.” The Internet offers near-infinite knowledge, but its architecture prizes speed over depth. Vannevar Bush’s 1945 dream of a “memex”—an early vision of hyperlinked information—anticipated Google and Wikipedia. Yet where Bush imagined a tool for exploration, we have created one for instant gratification. The result is what researcher Ethan Zuckerman calls the “serendipity deficit”: we consume more information than ever but stumble upon fewer surprises. In short, we have all the answers, but fewer questions.

Leslie’s historical arc reveals a sobering pattern: whenever curiosity is democratized, new forces arise to tame it. The Church once banned heresies; algorithms now filter our feeds. The lesson is timeless—each generation must reclaim curiosity from the systems that would domesticate it.

When information is abundant, curiosity becomes the new form of inequality. This is Leslie’s argument in The Curiosity Divide, a chapter that connects research in education, technology, and psychology to show how societies are splitting between the curious and the incurious. The divide isn’t about access to devices or Wi-Fi, but about how people use them: some explore, others escape.

Curiosity as Predictor of Success

Leslie highlights studies by psychologist Sophie von Stumm showing that intellectual curiosity predicts achievement as strongly as intelligence and conscientiousness. Together, these three traits form the “hungry mind index”—a better indicator of long-term success than IQ alone. In essence, curiosity transforms ability into accomplishment. Those who keep asking why push past plateaus; those who stop, stagnate.

Technology’s Hidden Divide

Contrary to digital utopianism, more access doesn’t guarantee more learning. Drawing on studies by Pew and the Kaiser Family Foundation, Leslie shows that poorer households spend more time online but use it less productively. Wealthier families treat the Internet as an encyclopedia; poorer ones treat it as a television. The same tool that could close opportunity gaps often widens them, creating what he calls a “time-wasting gap.”

This isn’t a moral failing—it’s a structural one. Time, energy, and learned curiosity are privileges unevenly distributed. In classrooms, too, fast broadband correlates with lower grades because uninspired students use screens for entertainment instead of exploration. As Leslie puts it bluntly, “When the Internet meets incuriosity, it becomes a mirror, not a window.”

Education and Motivation

Leslie critiques modern schooling for mistaking information availability for curiosity cultivation. He praises sociologist Annette Lareau, who found that middle-class parents practice “concerted cultivation,” actively encouraging their children to ask questions and negotiate with authority. Working-class families, constrained by resources, emphasize obedience and respect instead. The result? Middle-class kids grow up fluent in inquiry, ready to talk their way through systems that intimidate others. The rest learn silence.

Curiosity thrives where asking questions is a right, not a risk.

A Shrinking Space for Wonder

Cognitive polarization, Leslie warns, parallels economic inequality. As the curious grow more capable of navigating vast information landscapes, the incurious fall further behind. Universities, too, face this drift—students’ interest declines across four years of college as classrooms prioritize credentials over discovery. MOOCs (massive open online courses) promise intellectual democracy, yet fewer than 10% of enrollees finish. Without intrinsic motivation, curiosity can’t survive the solitude of the screen. The Internet gives everyone the same library, but not the same love of reading.

Ultimately, Leslie’s “divide” isn’t technological at all—it’s emotional, cultural, and cognitive. Curiosity has become both a privilege and a power. The digital age demands what psychologist Paul Silvia calls “effortful cognitive activity”—pleasure in thinking. Those who cultivate it will flourish in an information economy. Those who don’t will drown in what David Foster Wallace called the “tsunami of available fact.”

Leslie’s boldest claim is also his most counterintuitive: curiosity doesn’t die from too much knowledge—it dies from too little. Schools and reformers often romanticize children’s natural curiosity, arguing that formal education kills it by stuffing heads with facts. Leslie turns that argument upside down. Knowledge, he says, doesn’t smother curiosity; it sustains it. Without stored facts, curiosity has nothing to work on and nowhere to go.

Knowing Fuels Learning

Citing cognitive psychologist Daniel Willingham, Leslie explains that long-term memory is the true foundation of intelligence. Facts aren’t inert; they allow your mind to make connections, recognize patterns, and generate insight. Think of knowledge as soil—curiosity is the seed that grows in it. Without facts, your curiosity withers in abstraction. This principle explains why students who know more about a subject typically learn faster and deeper; prior knowledge expands their “zone of curiosity.”

The Myth of Skill-First Education

Leslie takes aim at “curiosity-driven” and skill-based education models inspired by Rousseau and revived by contemporary advocates like Ken Robinson. Their claim that schools should prioritize creativity over factual learning sounds noble but ignores science. Creativity isn’t free-floating; it’s combinational. To imagine a “golden mountain,” you first need to know both gold and mountains. Shakespeare’s brilliance, Leslie reminds us, came from mastering grammar drills and reading Cicero—not from coloring outside the lines. You can’t think critically without something to think about.

The Matthew Effect of Knowledge

Knowledge builds on knowledge. Drawing from sociologist E. D. Hirsch, Leslie describes education’s “Matthew Effect”: those who know more learn more, while those with small knowledge bases fall further behind. A child rich in vocabulary finds reading easier, which leads to more reading and still greater knowledge. A child who struggles, reads less, and the gap widens. Curiosity follows the same spiral—its rewards compound.

Stories That Prove the Point

Leslie tells of James Black, a gifted chess prodigy from a poor Brooklyn neighborhood. Through grit and curiosity, he became a national chess champion, yet failed an elite school entrance exam due to weak background knowledge. His curiosity couldn’t compensate for gaps in literacy and geography—facts he had never been taught. By contrast, middle-class children, surrounded by books and talk, unconsciously collect cultural capital that fuels further curiosity. The moral is simple: curiosity is fed, not born.

For Leslie, “knowing” isn’t the enemy of curiosity but its precondition. When you fill your mind with facts, you fill it with hooks for future wonder. Knowledge is not the final stage of learning but the platform from which curiosity can forever launch again.

Leslie closes with a practical manifesto—a set of principles for staying curious throughout life. They are not tricks but attitudes, drawn from real people who live by them: Stay Foolish, Build the Database, Forage Like a Foxhog, Ask the Big Why, Be a Thinkerer, Question Your Teaspoons, and Turn Puzzles into Mysteries.

1. Stay Foolish

Steve Jobs, echoing California countercultural guru Stewart Brand, urged graduates to “Stay Hungry, Stay Foolish.” Leslie interprets this as staying open to surprise—and resisting the arrogance of success. Like seventeenth-century China, which stopped exploring after centuries of dominance, organizations and individuals grow incurious once they think they know enough. Curiosity thrives on humility, the conviction that there’s always more to learn.

2. Build the Database

Advertising pioneer James Webb Young wrote that creative ideas come from connecting new knowledge to stored knowledge. By constantly “gathering raw material,” you fill your unconscious with material ready to recombine in novel ways. Curiosity isn’t only about following feelings; it’s about feeding your mind until inspiration strikes.

3. Forage Like a Foxhog

Borrowing from Isaiah Berlin’s essay The Hedgehog and the Fox, Leslie recommends combining depth and breadth. A “foxhog” knows one thing deeply but many things broadly, making creative leaps across disciplines. Think of Darwin, who read economics to refine his theory of evolution, or Charlie Munger, the investor who uses “multiple models” to understand the world.

4. Ask the Big Why

Negotiator Jonathan Powell, who helped broker peace in Northern Ireland, learned that curiosity—not cleverness—resolves conflict. Asking why transforms stalemates into understanding by revealing the motives beneath positions. The same applies in everyday life: curiosity about others’ perspectives breeds empathy and solves problems logic alone cannot.

5. Be a Thinkerer

Benjamin Franklin exemplified “thinkering”—mixing ideas with hands-on experimentation. He learned through tinkering with lightning, oil, and democracy alike. In the knowledge economy, Leslie argues, reconnecting thought and craft—ideas and implementation—is essential. Don’t just think. Do, test, and observe.

6. Question Your Teaspoons

Writer Henry James said the key to creativity is being “one of the people upon whom nothing is lost.” The Boring Conference in London celebrates that philosophy. Its talks on eggs, cash registers, and hand dryers show that even the mundane can yield mystery if scrutinized with care. Curiosity transforms boredom into fascination.

7. Turn Puzzles into Mysteries

Finally, don’t settle for the satisfaction of solved puzzles when lifelong mysteries beckon. Cryptographer William Friedman found joy not only in breaking codes but in contemplating the endless possibilities of language itself. The curious don’t seek closure; they seek expansion.

Across these principles, Leslie’s message is simple: curiosity is not a mood; it’s a method. It requires discipline, playfulness, and empathy. The reward, as T. H. White wrote in The Once and Future King, is inexhaustible: “The best thing for being sad is to learn something.”

If you adopt these habits, Leslie suggests, you’ll not only understand the world better—you’ll fall in love with it again. In an age that offers every answer, it takes courage to keep asking.