Just Babies

Have you ever wondered why even toddlers seem to know the difference between right and wrong—or why we sometimes feel compelled to punish others we’ve never met? In Just Babies: The Origins of Good and Evil, Yale psychologist Paul Bloom dives into the heart of these questions. Drawing on decades of research in developmental psychology, neuroscience, and moral philosophy, Bloom argues that our moral lives are simultaneously ancient and emergent: they are built on deep evolutionary foundations but shaped and refined through reason, reflection, and culture.

At its core, Bloom’s argument is simple yet profound: humans are born with an innate moral sense. Even babies, he shows, have early versions of compassion, fairness, and justice. But this moral sense is partial—it extends primarily to those close to us. To become truly moral adults, capable of compassion toward distant strangers and moral reasoning about fairness, we must use the tools of imagination and rational thought to expand beyond our natural boundaries. This transformation—from instinctive baby morality to reflective adult ethics—is the story Bloom wants to tell.

Moral Seeds in the Cradle

Bloom begins with evidence from studies of infants as young as three months old. Using clever puppet experiments, he and his collaborators discovered that babies consistently prefer “helpers” who assist others over “hinderers” who block them. They even engage in primitive acts of punishment—babies will reach for or reward the kind puppet and often avoid—or even strike—the unkind one. These findings, Bloom explains, suggest that some aspects of morality are not learned but are natural endowments of human evolution, akin to our capacity for language or vision.

This innate moral sense includes basic capacities such as empathy, compassion, fairness, and the desire to punish wrongdoers. Yet, as Bloom emphasizes, it’s not enough. Our evolutionary past also left us with dark instincts—tribalism, disgust toward outsiders, and cruelty toward those beyond our social circle. In this way, we inherit both goodness and evil from our biology.

Empathy, Fairness, and Punishment

Central to Bloom’s work is the role of empathy. Empathy, he notes, is both a blessing and a trap. It can push us toward compassion and altruism, but it also has limits—it is partial, biased, and often swayed by emotion. True moral progress, Bloom argues, comes not from empathy alone but from a deliberate compassion guided by reason. We need empathy to care, but reason tells us how to care wisely and fairly. Similarly, our innate sense of fairness leads toddlers to protest inequality and even destroy rewards if they’re not split evenly. But as we grow, reason allows us to refine fairness—rewarding effort, not just equality, and promoting justice over envy.

The Dark Side of Morality

Bloom does not romanticize human nature. Alongside empathy and fairness, we also carry impulses for revenge, prejudice, and disgust—emotions that can distort moral judgment. Disgust, for example, evolved as a survival mechanism to avoid poisons and pathogens. Yet over history, societies have turned this visceral feeling into a moral weapon, branding certain groups, classes, or sexual behaviors as “impure.” From caste systems to genocides, disgust has often been used to dehumanize. Similarly, our sense of belonging—so essential to cooperation—can twist into tribalism, causing intense loyalty to our kind and hatred toward outsiders. Bloom reminds us that our moral psychology evolved for small groups, not modern global societies, and that these instincts—while once adaptive—can now sow division and cruelty.

From Family to Humanity

To understand how morality grows, Bloom explores how our concern naturally radiates outward. We begin by caring for kin—the mother’s love that keeps a helpless infant alive. Then, through culture and cognition, this kin-based moral circle can expand to friends, neighbors, and even strangers. Yet, Bloom cautions, this expansion is not automatic. It requires reflection, stories, education, and, sometimes, religion or art to teach us empathy for those beyond our tribe. He cites the parable of the Good Samaritan, who helped an injured stranger despite belonging to an ostracized group, as an example of transcending parochial morality.

Bloom’s research also investigates the surprising forces that shape moral progress: social norms, fiction, and even television. He notes, for instance, that stories like Uncle Tom’s Cabin or shows like Will and Grace have expanded society’s moral imagination more effectively than philosophical arguments. At the same time, he warns that storytelling can also shrink the moral circle, fueling hate and fear when it dehumanizes others.

Reason: The Crowning Achievement

Where Bloom breaks from many contemporary moral psychologists is in his defense of reason. Against scholars like Jonathan Haidt, who see moral decisions as driven mostly by emotion and instinct, Bloom argues that rational thought is the most powerful tool of moral growth. He shows that over human history, reason has illuminated the blind spots of our moral sense: revealing the wrongness of slavery, sexism, torture, and cruelty. It helps us move beyond our evolved biases to craft impartial moral principles—echoing Kant’s call for universal laws and Peter Singer’s idea of the “expanding circle.”

Why It Matters Today

Bloom’s message is both humbling and hopeful. We may be born with moral tools, but we are not born moral heroes. Our instincts can lead to both kindness and cruelty; our fate depends on how we harness them. For Bloom, morality is not a divine spark bestowed from above but a human project—one built from biology upward, refined by learning, imagination, and reason. The book ultimately asks: how can we transcend the morality we are given to create the morality we need? The answer, Bloom says, lies in becoming more than just babies—using our minds to expand our hearts.

Paul Bloom opens his argument with a startling proposition: even babies—those who cannot walk, talk, or understand language—possess the rudimentary foundations of morality. Through ingenious experiments, he and his colleagues reveal that infants have an intuitive sense of good and bad, kindness and cruelty, fairness and unfairness. This discovery challenges the long-held assumption that morality is purely a product of culture or education.

Seeing Good and Evil Before Words

In one of Bloom’s hallmark studies, babies watched a puppet show: one puppet helps another climb a hill, while a second puppet pushes it down. After the show, when offered the choice between the helper and the hinderer, babies overwhelmingly reached for the helper. Even three-month-olds, using their gaze rather than their grasp, showed clear preferences for the kind character. These responses, Bloom argues, are early manifestations of a moral sense—an innate ability to evaluate social behavior.

Hardwired for Fairness

By their second year, children become miniature moral philosophers. They protest unequal distribution of treats, showing displeasure when someone gets more than they do—or, occasionally, even when they themselves receive the larger share. Experiments by Kristina Olson and Alex Shaw showed that younger children will sometimes throw away extra rewards rather than tolerate inequality. Their reactions show that fairness is not learned from textbooks or sermons—it’s largely built-in. (Psychologist William Damon reached similar conclusions decades earlier when interviewing children about fairness.)

Justice and Punishment

Even before language, babies display the seed of justice. They not only prefer the good puppet but also approve when the bad puppet is punished. In one experiment, toddlers chose to remove treats from a misbehaving puppet rather than reward it. By eight months, infants preferred a character who punished a wrongdoer over one who spared them. These findings suggest that moral reasoning begins before explicit instruction, echoing Adam Smith’s notion that humans are born with a “moral sense” analogous to the physical senses of sight or taste.

Biology Meets Culture

Bloom also connects this early morality to our evolutionary roots. Cooperation among kin was essential for survival, and natural selection favored beings inclined toward empathy and fairness. As biologist J.B.S. Haldane quipped, he wouldn’t die to save one brother but might for two brothers or eight cousins—a witty summary of evolutionary altruism. Yet, despite these natural dispositions, culture quickly shapes which behaviors we consider moral. Historical differences in attitudes toward issues like slavery, sexuality, and honor killings remind us that our innate morality is flexible, open to both enlightenment and corruption.

Ultimately, Bloom’s baby experiments force us to rethink what it means to be moral. Morality isn’t implanted by religion or learned solely through rules—it’s a natural inheritance. But as Bloom emphasizes, this inheritance is incomplete; it’s merely a starting point. To move from simple instincts of “nice” or “mean” toward sophisticated ethics of justice and rights, we need to grow intellectually and emotionally. Babies can judge, but only adults can deliberate.

If fairness lets us recognize justice, empathy lets us feel it. Bloom argues that empathy—the ability to experience another’s emotions—is part of our natural endowment. But it comes with paradoxes. While empathy can drive kindness, it can also bias us toward those we already like or resemble. In contrast, compassion—a broader and more cognitive concern for others—can avoid those pitfalls, guiding us toward wiser altruism.

The Missing Feelings of a Psychopath

To show empathy’s moral importance, Bloom introduces the chilling example of psychopaths—intelligent, charming individuals lacking remorse or concern for others. They know the difference between right and wrong but simply don’t care. Ted Bundy, for instance, could describe his murders with cold detachment. This lack of empathy, Bloom says, leads to moral emptiness. By contrast, ordinary children display empathy early: Darwin’s son, at six months, looked saddened when his nurse pretended to cry. Such vicarious sadness is the emotional root of compassion.

Empathy and Its Limits

Empathy, however, is selective. We naturally resonate with close relatives, friends, or those who fit our group identity, but we struggle to feel for strangers or enemies. Neuroscience confirms this bias: men empathize more with those who treat them kindly, while women’s empathy tends to be more universal. In some cases, empathy can even morph into schadenfreude—the pleasure of seeing others suffer. Thus, Bloom warns, empathy alone is not a reliable moral compass.

Compassion Without Empathy

Compassion, Bloom distinguishes, is not the same as empathy. You can help someone without sharing their pain. He cites philosopher Peter Singer’s example: if you see a child drowning in a shallow pond, most people would rush to help—not because they feel the child’s panic but because they know it’s the right thing to do. Compassion motivates rational kindness, while empathy risks emotional burnout or bias. Research shows that overidentifying with others’ pain can lead individuals to withdraw rather than help—mirroring an overwhelmed toddler who cries alongside a crying peer instead of comforting them.

Ultimately, Bloom concludes that a virtuous life depends less on feeling others’ emotions and more on caring for their well-being. True morality requires reasoned compassion—acknowledging suffering without being consumed by it. In doing so, we can extend care beyond our tribal instincts to strangers, enemies, and even future generations.

Fairness is one of the earliest and most powerful moral intuitions humans display. Bloom shows that from toddlers dividing toys to adults navigating justice systems, our judgments about fairness intertwine with emotions of envy, pride, and anger. Yet fairness isn’t always about equality—it also involves effort, merit, and punishment for wrongdoing.

Born to Be Equal, But Not Always Alike

Children have an instinct for fairness. In experiments by Alessandra Geraci and Luca Surian, infants as young as 16 months looked longer—signaling surprise—when rewards were distributed unequally. Slightly older children even destroy extra rewards to avoid inequality. When told to distribute candies between two characters, six-year-olds sometimes preferred to throw away the fifth candy rather than let one child get more. But Bloom notes that this equality drive can evolve into a concern for equity—rewarding those who work harder, as older children begin to do. Fairness, then, matures from mechanical sharing to moral reasoning about justice.

Status and Spite

Human fairness is inseparable from social comparison. Studies of children show that even at age five, kids are willing to forgo a reward if it means a rival gets less—a phenomenon called “inequity aversion.” Adults do the same. Bloom connects this to our evolutionary history: hunter-gatherer tribes maintained equality not out of benevolence but out of mutual vigilance—mocking or punishing anyone who rose too high. As anthropologist Christopher Boehm found, societies used ridicule to “cut down the tall poppy.” Fairness thus often grows out of envy and self-defense, not pure altruism.

Punishment and the Desire for Justice

Our appetite for justice extends beyond our personal interests. The ultimatum game shows that people will reject unfair offers even at a cost to themselves, revealing a willingness to punish for moral satisfaction. In Bloom’s view, this punitive instinct evolves from revenge—the primal need to defend one’s status—to a broader commitment to social order. Yet it’s a double-edged sword. The same outrage that sustains justice can turn into cruelty, mob vengeance, and moral hypocrisy. True progress, Bloom suggests, lies in transforming vengeful impulses into fair, impartial punishment—law instead of lynching.

Fairness, then, is not a simple equation. It’s a dynamic moral emotion that evolved to balance self-interest with cooperation. Our challenge is to refine these instincts—to harness our sense of justice without succumbing to spite. In Bloom’s words, our moral lives depend on learning not only how to share but when to fight back, and when to forgive.

Few emotions are as visceral—or as dangerous—as disgust. Bloom explores how a mechanism designed to protect us from disease has been hijacked to justify moral condemnation, racism, and cruelty. Disgust, he argues, is the emotion most easily weaponized against others, often masquerading as moral judgment.

From Rotten Meat to “Impure” People

Disgust evolved to help us avoid pathogens. The “yuck” reaction—scrunched nose, sealed mouth, nausea—kept our ancestors from consuming contaminated food. But humans expanded disgust beyond the physical to the social. Societies began treating entire groups—Jews under the Nazis, lower castes in India, slaves in America—as contaminating. George Orwell once observed that English class prejudice rested on the belief that “the lower classes smell.” As Bloom notes, the expression of disgust often precedes dehumanization.

Disgust and Sexual Morality

Disgust also shapes our judgments of sex. Acts like incest or homosexual relationships evoke moral condemnation far beyond concerns of harm. Bloom recounts Jefferson’s 18th-century proposal to punish sodomy by mutilation, noting how irrational disgust transformed personal choices into capital crimes. Disgust, he argues, acts as a cognitive shortcut: what feels revolting must be wrong. Yet this emotional logic is unreliable—what disgusts one culture may delight another. Evolution may explain why sex feels close to contamination—it involves bodily fluids—but it doesn’t justify moral persecution based on that feeling.

The Illusion of “Moral Purity”

Bloom examines psychological research showing that disgust makes people stricter judges. After watching a revolting film clip, participants delivered harsher moral verdicts on unrelated topics. Even smelling something foul—like “fart spray”—increased their disapproval of same-sex love. Conservatives, studies show, tend to score higher on “disgust sensitivity” scales, correlating with moral attitudes about purity and sanctity. Yet Bloom argues that tying morality to cleanliness produces hypocrisy: the same impulse that makes us wash our hands after wrongdoing can also lead us to ostracize those deemed impure.

Disgust as Moral Error

Ultimately, Bloom dismantles philosopher Leon Kass’s claim that disgust embodies “the wisdom of repugnance.” Far from being wise, disgust is fickle and often cruel. When it guided human judgment, it fueled slavery, genocide, homophobia, and oppression. True morality, Bloom contends, demands that we distrust our gut reactions and instead apply reason and compassion. If empathy tempts us to overcare, disgust tempts us to dehumanize. Moral maturity means knowing when to override both.

Our moral concern naturally begins with those closest to us. A mother’s self-sacrifice for her child or a soldier’s loyalty to comrades are moral instincts shaped by evolution. But these biases also draw dividing lines—between kin, tribe, and stranger—that constrain our compassion. Bloom explores how morality expands—or contracts—around these boundaries.

The Evolutionary Root of Family Love

Evolution favored parents who protected their young and kin who supported each other. Psychologist Alison Gopnik captures this in her metaphor of maternal devotion: a woman’s sleepless years nurturing a helpless child, behavior that would seem insane if aimed at a stranger. Bloom suggests that human morality evolved from this same parental template—care for the vulnerable extended through empathy into social compassion.

The Three Circles of Morality

Bloom defines three expanding moral circles: kin, in-group, and strangers. Toward kin, morality is instinctive—we help because their survival ensures our genetic success. Toward in-groups—friends, neighbors, or fellow citizens—we cooperate out of mutual benefit and shared norms. But toward strangers, nature gives no moral push. Extending kindness beyond our tribe is, in Bloom’s phrase, “a human accomplishment.” It emerges from imagination, empathy, and reason, not biology. Moral progress, he says, depends on deliberately widening these circles.

Tribal Biases and Their Transcendence

Studies show that even babies express in-group favoritism—preferring familiar faces, voices, or languages. This bias, harmless in infancy, later fuels racism and nationalism. Yet, Bloom notes, contact and cooperation can erase it. When children attend diverse schools, they stop associating morality with race. Similarly, shared goals—like solving a crisis—can dissolve divisions, as in experiments where rival summer camp groups became allies when faced with a common problem. Our challenge, Bloom observes, is to teach “Good Samaritan morality”: seeing the stranger as neighbor.

By tracing morality’s evolution from family love to universal compassion, Bloom shows that goodness requires imagination as much as instinct. We are moral animals, but our greatest moral achievements—abolishing slavery, defending human rights, helping distant others—require what nature never programmed: reasoned empathy that expands the moral circle until “stranger” becomes “another self.”

In his final chapter, Bloom takes a stand against a prevailing idea in modern moral psychology—the belief that reason merely serves emotion. While many argue, following David Hume, that “reason is the slave of the passions,” Bloom insists that rational reflection is the engine of moral advancement. Our instincts provide the raw materials; reason gives them shape and direction.

Beyond Instinct

Experiments by psychologists like Jonathan Haidt show that people often make moral judgments intuitively, justifying them afterward. We recoil at “wrong” acts—like harmless consensual incest—without being able to explain why. But Bloom argues that moral reasoning is not an illusion. Many of our firm moral principles—against slavery, torture, or fraud—rest on conscious reasoning about harm and fairness. Historical change, he notes, can’t be explained by gut feelings alone. It’s reason that has allowed humanity to recognize the equality of races, genders, and nations, transforming intuition into principle.

Thinking Morally

We use reason every time we moralize in daily life—debating fairness, questioning authority, or teaching children empathy through explanation (“How would you feel if someone did that to you?”). Children’s spontaneous appeals to fairness in play mirror philosopher John Rawls’s “veil of ignorance”—an intuition that justice means equal rules for all. Moral reflection, Bloom says, combines empathy’s insight (“others matter”) with logic’s reach (“all others matter”). Together, these forces forge impartial principles like the Golden Rule.

Reason as the Path to Growth

Bloom closes with optimism: though our morality begins in the cradle, it matures through reflection. We are capable of transcending our instincts—turning fleeting compassion into policy, outrage into justice, and bias into fairness. Morality, as he puts it, is a human construction, not divine revelation, built from “compassion, imagination, and our magnificent capacity for reason.” When you deliberately question your instincts—when you ask why something feels right or wrong—you are continuing an ancient human project: to make goodness not just natural, but intelligent.