The Truth About Trust

When was the last time you asked yourself, “Can I trust this person?”—your colleague, your partner, or even yourself? It’s a deceptively simple question that hides a lifelong gamble. In The Truth About Trust, psychologist David DeSteno argues that trust isn’t just moral virtue; it’s the biological and psychological engine behind human cooperation, success, and vulnerability. Every time you rely on someone else, you place a bet—not with money, but with faith in their integrity or competence. That wager, DeSteno contends, has shaped human evolution and continues to define the modern world—from romance and parenting to artificial intelligence and politics.

DeSteno’s core claim is that trust is a dynamic equilibrium between vulnerability and advantage. We are “built to trust” but equally built to betray. Through stories, experiments, and interdisciplinary insight, he shows that trust isn’t a fixed trait; it fluctuates depending on emotion, power, biology, and context. He combines evolutionary game theory, neuroscience, and social psychology to explain why trust persists despite risk—and how we can become smarter about using it.

Trust as a Gamble: The Fundamentals

At its foundation, trust is a wager on someone else’s intentions. You can’t verify their future actions, so you risk cooperation hoping long-term benefits outweigh short-term losses. This logic parallels the Prisoner’s Dilemma, the classic mathematical model of human cooperation. In it, two prisoners must decide whether to betray or cooperate with each other. Alone, betrayal seems rational, but together, mutual trust maximizes collective gain. Through this lens, DeSteno explains why trust makes sense despite danger—it’s a survival mechanism for a species whose success depends on teamwork.

The mind’s trust equations, he notes, evolved to weigh delayed rewards against immediate ones. This “ant versus grasshopper” conflict—echoing Aesop’s fable—defines all moral struggle. The ant saves food for winter (long-term gain); the grasshopper indulges now (short-term satisfaction). Our brains continually adjust this balance depending on stress, circumstance, and perceived safety. That’s why we may cheat, lie, or cooperate differently in different situations—not because our moral compass changes, but because our inner calculus does.

The Biology of Trust

DeSteno’s second argument dives deep into physiology. He demonstrates how biology doesn’t just reflect trust—it generates it. Drawing on the work of Stephen Porges and Sue Carter, he shows how the vagus nerve and the hormone oxytocin regulate feelings of safety and social connection. When calm and socially secure, vagal tone rises, promoting cooperation and empathy. Yet stress or betrayal drives us back to reptilian instincts—fight, flight, or freeze.

Oxytocin, often heralded as the “moral molecule,” is far more complex than popular science suggests. It bonds parents with children and lovers with partners—but also fuels tribalism and prejudice. You trust those like you and distrust the unfamiliar. As DeSteno writes, biology isn’t built for sainthood; it’s built for optimization. It favors trust when survival demands cooperation, and deceit when selfish gain promises advantage.

From Love to Machines: The Modern Stakes of Trust

Trust permeates everything—from romantic relationships to digital transactions. DeSteno shows how trust determines whom children believe, whom lovers forgive, and even how we interact with technology. In one experiment, people judged a humanoid robot named Nexi. When Nexi crossed her mechanical arms or touched her face, people sensed “dishonesty.” Without realizing it, their intuitive minds read universal nonverbal signals. The lesson: trust operates even when logic isn’t involved; we “feel” honesty through subtle patterns. These cues, when replicated in artificial intelligence, raise ethical dilemmas—machines might soon learn to manipulate human trust as well as people do.

Why This Book Matters

The real danger, DeSteno warns, isn’t gullibility—it’s misunderstanding trust itself. People seek absolute answers (“Always trust your gut” or “Never trust anyone”), but trust thrives in nuance. Learning when to trust, how to interpret emotional cues, and how to manage your own reliability is what separates successful partnerships from betrayal, resilient societies from collapse. Whether deciding to open up to a colleague, forgive a spouse, or delegate to a team, you’re negotiating unseen psychological forces that evolved over millennia.

In The Truth About Trust, DeSteno invites you to see trust not as blind faith but as strategic empathy—a scientific, emotional, and ethical art. He teaches that by understanding how biology, emotion, and context shape trust, you can avoid exploitation, build stronger bonds, and even confront the hardest test of all: trusting yourself.

You might think trust is purely psychological—a matter of choice or circumstance—but David DeSteno shows it’s written into your body’s wiring. Our brains and hearts literally change when we decide whom to trust. This biological foundation reveals a surprising paradox: we are hardwired both to bond and to betray.

The Three Systems of Survival

Based on Stephen Porges’s Polyvagal Theory, DeSteno describes three neural circuits inherited from evolution. First, the unmyelinated vagus triggers freezing—a reptilian defense against predators. Second, the sympathetic-adrenal system creates our “fight or flight” reaction. Finally, the myelinated vagus, unique to social mammals, calms the body and supports connection. When this latter system dominates, we feel safe, our hearts slow, and we’re primed for cooperation. When suppressed, our instincts revert—mistrust, aggression, avoidance. This hierarchy explains why betrayal feels so visceral; it flips you from mammalian serenity to reptilian defense in seconds.

Oxytocin and the Double-Edged Sword of Love

Oxytocin, the famed “trust hormone,” strengthens emotional bonds but also reinforces group boundaries. It can make parents care and lovers connect, yet also inflame discrimination and envy. In experiments by Carsten De Dreu, participants sprayed with oxytocin became more cooperative with people like themselves—and more biased against outsiders. DeSteno summarizes: biology doesn’t make you moral; it makes you efficient. You trust when trust aids your survival and turn selfish when it doesn’t.

Primate Lessons in Fairness

In a striking set of studies, DeSteno cites Sarah Brosnan’s monkey economy. When two capuchins completed identical tasks but one received tastier fruit, the slighted monkey threw food back at researchers in protest. Even chimpanzees refused unequal rewards, revealing fairness isn’t taught—it’s ancient. We share this instinct because cooperation demands reciprocity. And, like people, monkeys also refused excessive advantage—they knew unfair privilege jeopardizes future trust. As DeSteno concludes, fairness isn’t morality—it’s strategy.

“We’re built to trust and to betray—because survival requires both.”

This balance of competing instincts ensures humans adapt to changing dangers. It’s not saintliness or sin that drives trust, but what optimizes survival at the moment.

Evolution endowed you with systems for compassion and caution alike. Knowing when each activates—your calm voice or your racing heart—is the key to managing trust wisely.

Imagine a child asking endless questions: “Why is the sky blue?” “Can I have pizza every night?” DeSteno shows that behind such curiosity lies the first lesson in trust. Children must trust others to learn, because they haven’t yet developed the tools to verify reality themselves. The process of learning, then, becomes their first moral negotiation.

Why Children Trust—and Whom They Believe

Through psychologist Paul Harris’s studies, DeSteno reveals that by age three, children already differentiate between trustworthy and untrustworthy adults. They prefer to learn from caregivers proven reliable, not merely familiar. When kids saw two teachers name objects differently, they favored the “accurate” teacher three times more—even a week later. Trust shapes learning longevity: children remember lessons better when told by someone they believe has integrity.

Competence vs. Familiarity

While parents may assume love guarantees trust, kids weigh expertise higher than affection. When a trusted caregiver repeatedly misnames familiar items, preschoolers seek knowledge from strangers. By age five, competence outweighs comfort—echoing Amanda Ripley’s school findings that students learn most from teachers they respect, not those they “like.” DeSteno extends this into adulthood: trust thrives on perceived capability as much as kindness.

Born with Moral Calculators

Even before speech, babies display fairness instincts. In Felix Warneken’s experiments, toddlers spontaneously helped adults retrieve dropped objects. Yet when rewards entered the equation, their sense of justice sharpened—they divided stickers based on effort but never gave more than half away. By age eight, children reject unfair advantages if witnessed publicly. Like adults, they balance self-interest and cooperation, proving trustworthy behavior isn’t taught—it’s calibrated.

DeSteno’s insight reframes education: teaching and parenting are acts of trust exchange. To learn, children must believe in an instructor’s integrity and ability. To teach, adults must uphold trust by modeling fairness. Education, then, is humanity’s first partnership contract.

Romantic relationships are the most high-stakes trust exercise of all. In love, you bet not just resources, but your emotional security. DeSteno describes trust as the cognitive shortcut that makes intimacy possible—and betrayal devastating. Without it, love collapses under constant verification; with it, couples navigate storms with grace.

From Exchange to Communion

Early relationships follow an exchange-based logic: “If I cook dinner, will she pay next time?” Over time, partners who consistently meet expectations transition into communal relationships. Psychologist Margaret Clark proved it with ink colors: in experiments, partners in communal relationships used the same colored pens when marking shared tasks—signaling unity—while transactional pairs insisted on different pens to track fairness. Trust turns calculation into compassion.

Jeffry Simpson’s Strain Tests

In psychologist Jeffry Simpson’s “strain-test” studies, couples discussed painful sacrifices—career moves, relocations, financial risks—under observation. Those high in trust showed calm accommodations and collaborative tones. They forgave small lapses instinctively, even misremembering partner behavior as more generous than it was. Their brains create positive illusions to preserve harmony—DeSteno compares this to the Generous Tit-for-Tat strategy: forgiving noise to ensure long-term cooperation.

The Role of Intuition in Romance

Yet trust isn’t purely rational. Psychologist Sandra Murray found couples’ unconscious impressions (“gut trust”) predict survival better than conscious analysis. When stressed or exhausted, partners rely on intuition—what DeSteno calls neuroception—to sense loyalty through tone and pattern. The result: those high in intuitive trust stay close even through uncertainty; those low retreat despite logic. Love, he writes, is biology’s most efficient trust algorithm.

In relationships, trust lubricates cooperation, cushions conflict, and sustains belief in redemption. Our illusions of loyalty aren’t flaws—they’re adaptive code, designed to keep connection alive long enough for hearts—and genes—to flourish.

“Get out of my way.” That phrase, captured in Paul Piff’s San Francisco street study, sums up the psychology of trust among the wealthy. DeSteno explores how power and abundance erode trust by reducing dependence. When you can buy cooperation, you don’t need faith—and empathy fades.

The Wealth Effect

Piff’s team found that luxury car drivers cut off pedestrians twice as often as others. In lab tests, upper-class participants lied more, cheated more on dice rolls, and judged deceit as acceptable. The reason isn’t inherent immorality—it’s perceived independence. Abundance makes vulnerability optional, so empathy diminishes. Trust, DeSteno says, “is what the poor use to survive and the rich forget they need.”

Power’s Corruption and Hypocrisy

In Adam Galinsky’s simulations, participants given temporary authority rationalized unethical acts. They applied moral leniency to themselves, strictness to others. Power, Dana Carney showed, even enhances deception—it steadies nerves and masks guilt, making lies harder to detect. These subtle shifts recreate the privilege paradox: the powerful believe they can bend rules and avoid consequences.

The Midas Touch

Money isolates. Francesca Gino and Kathleen Vohs found that proximity to cash or symbols of wealth increases selfishness, reduces collaboration, and heightens self-focus. Participants exposed to physical money cheated more, helped less, and sat farther from others. Wealth cues turn our minds inward—diminishing the very trust that builds societies.

DeSteno’s conclusion echoes evolutionary logic: vulnerability sustains honesty. When success severs interdependence, trust decays. Yet power can recover compassion—leaders who remain socially engaged and emotionally intelligent, as Dacher Keltner notes, renew trust through empathy. The antidote to corruption isn’t less privilege; it’s more connection.

Can you really tell if someone’s trustworthy? DeSteno tested this through years of experiments, first with human pairs, then with robots. His findings shattered myths about lie detection: there’s no single “tell.” Trust signals arise not from isolated gestures but from dynamic patterns of movement and context.

The Subtle Code of Trust

Across hundreds of conversations, DeSteno’s team found four cues that correlate with untrustworthiness: crossed arms, leaning away, touching the face, and fidgeting with hands. These behaviors expressed disengagement and anxiety—markers of selfish intent. Yet people weren’t consciously aware of using these signals; intuition did the decoding automatically. When participants could see partners face-to-face, they predicted fairness 37% more accurately than online counterparts.

The Robot Experiment

To isolate causality, DeSteno worked with roboticist Cynthia Breazeal and her humanoid robot Nexi. By programming Nexi to express trust cues or neutral behaviors, they found that humans instinctively distrusted Nexi when she crossed her mechanical arms or leaned back—even when they knew she was a machine. This confirmed that the mind’s “trust radar” works on pattern recognition, not intent. Our brains judge honesty through motion, not morality.

Reading Configural and Situational Context

DeSteno dismantles pseudo-science from “Lie to Me”-style theories. Expressions mean different things depending on context. A smile can signal joy or deceit; furrowed brows can reflect triumph or anger. Psychologists Lisa Feldman Barrett and Hillel Aviezer proved that emotion cannot be read from faces alone—it requires body configuration and circumstance. Trust, likewise, emerges from sets of cues, not single movements.

Understanding these patterns reveals why intuition sometimes beats reason. The “blind men and the elephant” metaphor fits perfectly—you can’t see truth by feeling parts. Our minds evolved to integrate complexity effortlessly; learning to respect that instinct lets you read people more precisely than any lie detector ever could.

Would you trust a robot, avatar, or AI? DeSteno tackles the digital frontier, warning that technology now manipulates human trust through precision cues. As communication moves online, we’re entering a world where artificial companions read and even shape our emotions.

Trusting Technology’s Competence

The “white coat effect”—our tendency to trust anyone who looks expert—extends to technology. In Joseph Lyons’s Air Force studies, participants trusted computer advice over human judgment during risk scenarios, convinced of machines’ superior competence. DeSteno warns: this bias empowers manipulation. “The MRI effect” makes colorful brain scans appear infallible though most misinterpret them.

Avatars and the Proteus Effect

Virtual avatars and agents mimic social behavior so well that we treat them as real. Jeremy Bailenson’s research showed users cooperated more with avatars resembling themselves—even subtly morphed faces increased trust and political preference. Yet in Nick Yee’s Proteus experiments, players controlling taller avatars acted more selfishly, even beyond the game. Digital identity alters morality; what we play can shape who we become.

Technology That Heals

Technology can also enhance trust for good. Timothy Bickmore’s virtual nurse “Louise” helped low-health-literacy patients better understand care after hospitalization. Patients trusted her empathy, interacted longer, and remembered more instructions. Likewise, Facebook’s Arturo Bejar used algorithms to connect bullied teens with similar, compassionate peers—leveraging trust through perceived similarity. When designed ethically, technology can build the very trust it risks destroying.

As social robots and AI grow more lifelike, humans face an evolving moral test: balancing efficiency with empathy. Cybertrust isn’t about software—it’s about safeguarding the essence of human connection in a synthetic age.

Perhaps the hardest question of all isn’t “Can I trust you?” but “Can I trust myself?” DeSteno’s experiments reveal the uncomfortable truth: even honest people cheat when temptation strikes—and rationalize it afterward.

The Coin Flip and Moral Hypocrisy

In one study, participants were told to flip a coin to choose who completed a fun or boring task. All agreed cheating would be immoral. Yet 90% didn’t flip—they simply took the better option. When watching others cheat, they condemned them; when cheating themselves, they justified it. DeSteno calls this moral hypocrisy: we preserve self-image through rationalization rather than reality.

Forward-Looking Myopia

We falsely assume we’ll resist future temptations. Psychological studies by Dan Gilbert and Kathleen Vohs show how hunger, stress, or fatigue distort willpower. In Vohs’s ice-cream experiment, dieters who resisted nearby snacks later binged. Willpower, it turns out, is finite. The more we trust our rational selves, the more our emotional selves betray us.

Rearward-Looking Whitewash

After wrongdoing, we erase guilt with excuses. DeSteno’s participants under cognitive load—unable to rationalize—finally admitted unfairness. Without distraction, the brain rewrites history to preserve virtue. Eliot Spitzer’s confession after his scandal epitomized this: he blamed stress, not desire. The mind whitewashes betrayal to stay functional, not truthful.

DeSteno urges humility: acknowledge your fallibility. Willpower isn’t infinite; intuition must guide morality when reasoning falters. Apps and habits that “let your past self speak to your future self” are modern aids against cognitive blindness. The key, he concludes, is not perfection but awareness—knowing when your impulses, not your ethics, are steering your choices.

When disaster strikes—Katrina’s floods, Boston’s bombing—trust reveals its power. DeSteno ends his book with real stories showing that trust isn’t sentiment; it’s civic glue. In Gulfport, Mississippi, Hancock Bank distributed millions after Katrina with nothing but handwritten IOUs. People repaid nearly every dollar. The result wasn’t bankruptcy—it was rebirth.

Trust and Collective Resilience

After the Boston Marathon bombing, residents opened homes to strangers, offered rides, and comforted victims. Vulnerability unlocked empathy. Across crises, sociologists find neighborhoods with higher trust recover fastest. In that sense, trust isn’t just moral—it’s infrastructural. It rebuilds cities as well as hearts.

The Six Rules of Trust

• Trust is risky but necessary: it’s how societies evolve.
• Trust pervades life: not just money or love, but learning, technology, and health.
• Examine motives, not reputation: people’s trustworthiness shifts moment to moment.
• Pay attention to intuition: your gut often knows what reason ignores.
• Embrace forgiving illusion: misunderstanding can protect bonds.
• Cultivate trust from the bottom up: teach gratitude, humility, and empathy—not just willpower.

His final message echoes through social science and philosophy alike (similar to Brené Brown’s Daring Greatly): trust transforms vulnerability into strength. It’s not naïve hope—it’s adaptive courage. Every act of faith, every cooperation, every forgiveness, keeps humanity from collapsing into dust.