Born Liars

Have you ever wondered why people lie even when it would be easier to tell the truth? In Born Liars, Ian Leslie argues that deceit is not a moral failure but an evolutionary triumph. Far from being a destructive habit we must eliminate, lying is deeply woven into human nature — as essential to our survival, social bonding, and creativity as language itself. Leslie contends that our minds are not built to seek only truth but to navigate the complex social realities of human life, where deception often helps us cooperate, persuade, and protect ourselves.

The book opens provocatively: not even God is exempt from deceit. In Genesis, Leslie points out, God tells Adam and Eve they will die the day they eat the forbidden fruit, but they do not. From the very beginning of human storytelling, lies coexist with morality. Leslie pushes readers to confront a paradox — that honesty is socially necessary, but deceit is psychologically inevitable. Across chapters that combine history, psychology, neuroscience, and philosophy, he shows that lying is not a deviation from our better selves but part of what makes us human.

Deceit as Evolutionary Advantage

Leslie draws on research by primatologists like Richard Byrne and Andrew Whiten, who developed the theory of "Machiavellian Intelligence." They discovered that primates with larger brains tend to be better deceivers. Baboons and chimpanzees use deception strategically — pretending to spot predators to distract rivals or feigning indifference to hide coveted food. Humans, he notes, evolved in intensely social environments where survival depended less on brute strength and more on social cunning. By learning to manipulate appearances, anticipate others’ beliefs, and mask intentions, early humans gained an evolutionary edge. Deception became a form of intelligence, not immorality.

The Cultural Paradox of Honesty

In modern society, we condemn lying while practicing it constantly. Leslie cites studies by psychologists Bella DePaulo and Robert Feldman showing that the average person lies 1–3 times daily, even in casual conversation. We lie to smooth social friction (“I’m fine, thanks”) or to avoid hurting others (“You look great”). From white lies to diplomatic deceit, our interactions depend on carefully managed falsehoods. Leslie leverages philosophy and history to show how thinkers like Kant and Augustine treated lying as a moral contagion, while Nietzsche and Wilde saw it as an art — a creative rebellion against dull reality. We oscillate between these views, demanding total honesty while thriving on illusion.

Science of Detection and Self-Deception

The book traces humanity’s attempts to scientifically decode lies, from the invention of lie detectors by John Larson in Berkeley to modern brain-scanning technologies like fMRI. Leslie tells lively stories — such as how the CIA’s Aldrich Ames passed lie detector tests while spying for the Soviets, revealing that machines can’t measure truth because even honest people show “guilty” physiological signals. More troubling, Leslie shows how interrogation tools and false confessions (like in the Norfolk Four case) blur the line between truth and fabrication. At the same time, neuroscience exposes how our brains fabricate stories to make sense of the world. Split-brain experiments by Michael Gazzaniga demonstrate that the mind’s left hemisphere acts as an “interpreter,” inventing plausible explanations for actions it doesn’t understand. In this way, every person is a confabulator — someone lying to themselves to preserve coherence.

Self-Deception and Society

Leslie moves from lies to deeper forms of self-deception, exploring Shelley Taylor’s concept of “positive illusions” — our tendency to overestimate our competence, morality, and control over life. These illusions, though false, make us resilient, creative, and even happier. When we compare this to depressed individuals who see reality more accurately (“depressive realism”), it becomes clear that some delusion is necessary for mental health. Leslie connects this psychology to leadership and history: overconfidence drives entrepreneurs and military commanders like Pizarro but also causes catastrophic wars when collective deception spirals, as in Saddam Hussein’s Iraq. Lies, he suggests, scale up from individuals to institutions, shaping politics, war, and peace.

The Moral Landscape of Lies

Finally, Leslie reframes morality itself: lying is not merely wrong but contextually human. He revisits the classic “murderer at the door” dilemma from Kant and Augustine through real stories like Corrie ten Boom’s wartime deception to save Jews. The question becomes not whether to lie but when and why. Lies can protect life, sustain love, and create meaning. They can also destroy trust and warp reality when unchecked. Leslie concludes with a practical philosophy of honesty — suggesting that truth is best pursued collectively, through dialogue and doubt, not through rigid absolutes. “Honesty is something we do together,” he writes, echoing the scientific, democratic, and moral systems that rely on shared enquiry to approach truth.

In sum, Born Liars argues that to understand deceit is to understand ourselves. By exploring how we lie to others and to ourselves — in science, love, politics, and art — Leslie shows that deception is not humanity’s flaw but its signature. The challenge isn’t to live without lies but to live, consciously, with them.

Leslie traces lying back to our evolutionary origins. Drawing on Nicholas Humphrey’s paper The Social Function of Intellect, he explains that our intelligence evolved less from mastering nature and more from mastering relationships. Palaeolithic humans needed to read others’ intentions, bluff, and conceal desires — skills that demanded complex cognitive abilities. It wasn’t the battle against predators that shaped our minds, but the battle of wits with other humans. In this view, deceit is the original social technology.

From Apes to Humans: Machiavellian Intelligence

Richard Byrne and Andrew Whiten found that the frequency of deception in primates correlates with brain size. In one example, a baboon pretends to spot a predator to distract rivals from food. Another chimp hides its digging efforts when a stronger male appears. Such tactics reveal awareness of others’ mental states — a precursor to theory of mind. Robin Dunbar expanded this idea, showing that bigger brain cortices correlate with larger social group size; humans evolved to handle about 150 stable relationships. The evolutionary arms race between liar and lie-detector shaped the complexity of our minds.

Language: The Final Leap

When language arrived, deceit exploded. Unlike a gesture, a verbal statement could detach reality from action. “There’s food over there,” could be true or false without immediate verification. Language made lying cheap — and extremely effective. As Leslie notes, it allowed humans to manipulate not only situations but the perceptions of others in absentia. Remarkably, societies codified lying into art (through storytelling and rhetoric) even while condemning it ethically.

“We are simultaneously appalled by our ease with falsity and impressed by our creativity,” Leslie writes, merging evolutionary logic with moral ambivalence.

In an evolutionary sense, truth-telling would be maladaptive if total honesty exposed vulnerability. Lying, therefore, served a social purpose: lubrication, persuasion, survival. To be human is to be both storyteller and strategist.

Children’s lies offer a window into how deceit develops naturally. Leslie cites the psychologist Victoria Talwar, whose research on the “Peeking Game” reveals that by age four, most children lie convincingly when caught peeking at hidden toys. Between ages three and six, lying becomes thoughtful rather than impulsive — it requires theory of mind and executive function. In other words, to lie, you must understand what others believe and manage your body language to sustain the illusion.

The Milestone of Mind-Reading

Leslie explains the Sally-Anne test, which shows children’s growing ability to infer false beliefs. A three-year-old assumes everyone knows what she knows; a five-year-old recognizes that others can believe wrongly — and thus can be deceived. Developmental psychologists like Simon Baron-Cohen link this cognitive revolution to the rise of deceit. Autistic children, who struggle with perspective-taking, seldom lie because they cannot imagine another person’s mind. Lying, then, is evidence of advanced empathy, not moral decay.

Culture and Discipline

Talwar’s cross-cultural studies in West Africa reveal how social environments shape lying. In lenient schools, children lied occasionally and clumsily; in punitive schools, even three-year-olds lied masterfully, denying wrongdoing with calm precision. Harsh punishment doesn’t eliminate deceit — it perfects it. “If you’re going to get punished for small things,” Talwar told Leslie, “you may as well go for broke.” This aligns with François de La Rochefoucauld’s insight: “The weak cannot be sincere.” Lying becomes adaptive self-protection.

Morality and Growth

Leslie compares stories used by Talwar — The Boy Who Cried Wolf (fear-based teaching) versus George Washington and the Cherry Tree (virtue-based teaching). Children exposed to the compassionate story were more honest, not because of fear, but because truth brought pride. The lesson: honesty grows best in environments of trust rather than intimidation. As for lying, it marks the dawn of imagination — the moment a child discovers inner worlds where facts bend to desire.

By reframing childhood deceit as a cognitive milestone, Leslie redefines lying as developmental success. When a child invents a story, hides a mistake, or whispers “I didn’t peek,” she’s not just lying — she’s learning to think.

Leslie devotes a fascinating chapter to humanity’s obsession with building a “truth machine.” From the 1921 invention of the polygraph to modern fMRI scanners, we dream of erasing ambiguity from morality. Yet each generation’s truth technology reveals more about belief than reality. The story begins with John Larson in Berkeley, whose early lie detector supposedly caught a student thief, and grows into a drama about ambition, rivalry, and moral doubt.

The Birth of the Polygraph

Larson and his collaborator Leonarde Keeler built the cardio-pneumo-psychograph: a machine measuring pulse, breath, and blood pressure. Berkeley’s police chief August Vollmer hailed it as the future of humane interrogation. The press celebrated “Science Nabs Sorority Sneak!” after a suspect confessed under the polygraph’s pressure. But Larson later regretted his creation — retesting “guilty” people revealed readings similar to innocent ones. The machine measured anxiety, not lies. His colleague Keeler commercialized it, selling polygraphs to corporations, whereas Larson saw only moral peril.

Ames and the Machine’s Myth

Decades later, CIA spy Aldrich Ames easily passed polygraph tests while betraying U.S. secrets. His mocking letter from prison called the polygraph “a coercive aid to interrogators, halfway between a truncheon and a diploma.” Leslie quotes this to illustrate how faith in technology often substitutes for truth itself. The device’s authority rests on fear, not accuracy.

The Modern Truth Machines

Leslie updates the story with fMRI and EEG “lie detection.” Scientists claim to spot deception through brain waves or oxygenated blood flows — the colorful maps of dishonesty. Yet, as he shows, these methods stumble on memory, perception, and emotion. How can machines distinguish a lie from a false memory or repressed trauma? In one haunting case (the Norfolk Four), coerced confessions brought convictions later disproved by DNA. As psychologist Saul Kassin says, “Juries are bound to convict” once a confession exists — even if false.

Leslie concludes that our fascination with truth machines reveals a deeper lie — the fantasy that truth resides inside individuals rather than between them.

In the end, our instruments may never find truth because truth itself is relational — it lives not in physiology but in dialogue, evidence, and interpretation.

No chapter in Leslie’s book is more personal than his exploration of self-deception. Drawing on psychologists like Shelley Taylor and Leon Festinger, he shows that human happiness depends on well-maintained illusions about competence, control, and goodness. We deceive ourselves not because we are weak but because without deception we would collapse under the weight of reality.

Positive Illusions: The Healthy Lies

Taylor found that people who recover best from trauma — rape victims, cancer survivors — often hold unrealistically optimistic beliefs about their future. They lie to themselves, and those lies heal. These illusions fall into three categories: superiority (“I’m smarter than average”), unrealistic optimism (“My future will be better”), and control (“My actions shape outcomes”). Without them, life feels unbearable. As Leslie notes, those with fewer illusions show more depressive realism — accuracy without joy.

Confidence and Overreach

Leslie connects positive illusions to success. Joanna Starek’s study of competitive swimmers found that those who scored high in self-deception performed better — their “championship thinking” fueled triumph. Similarly, entrepreneurs, artists, and generals thrive on overconfidence. Adam Smith saw this in ambition’s “poor man’s son,” whose self-delusion built civilization. Yet, overconfidence births catastrophe — from AOL-Time Warner’s merger to Iraq’s invasion. Optimism, unchecked, becomes delusion.

War, Politics, and Delusion

Leslie uses historical dramas — Pizarro’s conquest of Peru and Custer’s defeat — as metaphors. Both leaders acted on illusions of control. Only luck distinguishes the visionary from the doomed. In Saddam Hussein’s Iraq, self-deception turned lethal: ministers lied to avoid punishment, until “everyone started lying.” Saddam himself believed his own fabrications about weapons, tricking both his people and the West. Leslie invokes biologist Robert Trivers: we evolved to deceive ourselves first, so we could deceive others more convincingly.

From optimism to authoritarian delusion, Leslie’s message is clear: lies sustain but can consume. The line between illusion and delusion is thin — what saves our sanity can also endanger our species.

Leslie’s discussion of medical deception is among the book’s most illuminating. The placebo — Latin for “I will please” — becomes proof that lies can heal. He recounts the wartime discovery of the placebo effect by Henry Beecher, an army medic at Anzio who administered salt water in place of morphine when supplies ran out — and saw miraculous relief. His realization changed modern medicine.

Healing Through Faith and Fraud

Beecher’s 1955 paper “The Powerful Placebo” argued that belief itself triggers physiological change. When patients think they are treated, endorphins and immune responses activate — even if the treatment is fake. Leslie highlights Fabrizio Benedetti’s modern research showing that placebos stimulate neurological pathways identical to real drugs. “A lie heals,” writes Leslie, “because it has meaning.” The doctor’s confidence, the hospital’s symbols, and the ritual of treatment form emotional scaffolds of recovery.

Mesmer and the Origins of Suggestion

To show that healing by illusion predates science, Leslie tells the story of Franz Mesmer’s “animal magnetism.” His theatrical healing ceremonies in eighteenth-century Paris, debunked by Benjamin Franklin’s commission, demonstrated that imagination itself could cure. Franklin concluded that Mesmer’s powers came not from magnetism but “the influence of imitation and imagination” — the first scientific defense of psychological healing.

Meaning, Symbol, and the Modern Doctor

Leslie argues that medicine’s obsession with biochemistry ignores the mind’s power to create meaning. Cultural rituals — from white coats to branded pills — amplify placebo effects. In other words, healing depends partly on shared belief. Paradoxically, the ethics of deception persist: should doctors tell “helpful lies”? Leslie concludes that honesty in medicine need not mean full disclosure; sometimes truth must serve healing, not knowledge.

By merging psychology, neuroscience, and history, Leslie elevates placebo from trickery to testimony — proof that lies can save lives as much as truths.

Leslie’s exploration of memory reveals the fragility of truth itself. Psychologist Elizabeth Loftus proved that memories are not records but reconstructions — easily warped by suggestion. In her famous experiments, participants recalled being lost in a shopping mall or meeting Bugs Bunny at Disneyland after researchers planted false stories. Leslie links such findings to real miscarriages of justice, especially false confessions.

The Norfolk Four and Confession Psychology

In Virginia, four sailors confessed to a murder they didn’t commit after days of interrogation. DNA later exonerated them, but juries couldn’t ignore their confessions. Kassin’s research shows that once a confession exists, it contaminates all evidence — witnesses reinterpret memories to fit it; experts shift judgments. “A confession is the nuclear weapon of evidence,” Kassin warns. We believe words because they satisfy our need for narrative coherence.

False Memories and Cultural Panics

Leslie recounts Paul Ingram’s tragic case: accused of satanic abuse by his daughters, he came to believe his own guilt after coercive hypnosis. Psychologist Richard Ofshe tested him by inventing a crime — Ingram soon “remembered” it vividly. Like Loftus’s participants, he filled memory’s gaps with story. Leslie shows that truth collapses when belief and suggestion converge; the mind rewrites its own history. Freud foresaw this, writing that childhood memories “are formed at the time we recall them.”

Leslie’s conclusion: our need to explain overrides our need to verify. In confessions, trials, and everyday life, we swap evidence for narrative. Lies comfort because they make chaos make sense.

In his philosophical finale, Leslie confronts the moral dimension of deceit through history — from Augustine’s condemnation to Kant’s icy absolutism. Using the famous murderer at the door thought experiment, he questions whether truth can ever supersede compassion. The story of Corrie ten Boom, who lied to Nazis to protect Jewish refugees, proves that absolute truth may be immoral.

The Church’s Battle Over Equivocation

Leslie traces centuries of theological wrestling with lying, including Catholic casuistry’s doctrine of “mental reservation,” where priests could inwardly add phrases that made false statements true (“He is not here — to you”). Such reasoning saved lives during persecution but later fueled scandals like Irish clergy’s evasions over abuse. Moral absolutes crumble when honesty endangers justice.

From Kant to Confucius

Contrasting Western moral rigidity with Eastern pragmatism, Leslie cites Kang Lee’s study of Chinese vs. Canadian children: Chinese children praised those who lied modestly about good deeds. Rooted in Confucian ethics, lying preserves harmony and collective welfare. Western norms, grounded in individual rights, demand honesty even at social cost. The moral question shifts from truth itself to relational context.

Shared Truth as Collective Honesty

Leslie’s closing argument — “Honesty is something we do together” — reframes truth as a collaborative act, sustained by scrutiny, empathy, and mutual correction. Democracies, he argues, require institutions that check deceit and reward transparency, not perfect truth-tellers. Lies may be inescapable, but systems of evidence and dialogue keep them from tyranny.

By ending with this ethic of collective truth, Leslie transforms a bleak diagnosis into a hopeful prescription: we cannot eliminate lying, but we can share the work of honesty.