The Human Swarm

What makes a society more than a crowd of cooperating individuals? In The Human Swarm, biologist Mark Moffett argues that the secret lies not in cooperation itself but in identity—our ability to recognize, imagine, and sustain membership in groups vastly larger than our circle of personal acquaintance. He suggests that humanity’s success depends on the evolutionary leap from personal recognition (who you know) to symbolic recognition (who belongs).

Membership over cooperation

Moffett begins by redefining what a society is. Cooperation alone, he says, cannot hold together a nation or even a tribe for long. Instead, a society endures because its members share an imagined boundary between “us” and “them.” You and millions of fellow citizens form an entity that exists in your minds—a modern rendering of what Benedict Anderson called an “imagined community.” (Note: Moffett extends Anderson’s insight beyond nations, showing that the same principle applies to every social species that maintains stable membership.)

Recognition systems across species

To illuminate how this works, Moffett compares the ways animals manage recognition. Chimpanzees rely on individual memory; ants, by contrast, depend on chemical markers. The first limits scale—you can’t recall thousands of acquaintances—while the second allows the creation of “supercolonies” numbering in the billions. Humans managed to combine both: we know friends individually, but we also wield markers—language, style, or ritual—that let us trust strangers as fellow members of our society. The result is the capacity for anonymous yet cohesive communities.

Markers and the evolution of complexity

The leap to symbolic membership began long before recorded history. Moffett links the evolution of vocal calls like chimpanzee pant-hoots to the development of early human “passwords.” Over time, these evolved into visual and auditory badges—tattoos, ocher, ornamentation, chants—that operated as proof of membership. Archaeological finds at Blombos Cave and Pinnacle Point support this early emergence of symbolic identity technology as far back as 160,000 years ago. Such markers let groups grow without everyone knowing each other personally.

From bands to civilizations

Hunter-gatherer bands reveal the flexibility of early social life. Typically made up of 25 to 35 people, bands divide and reunite in what anthropologists call “fission-fusion” dynamics. Members share resources, resist hierarchy, and use ridicule and mobility to prevent dominance. But once populations settled—on fertile coasts or near permanent food sources like salmon runs—societies became hierarchical. Storage led to specialization, hereditary leadership, and inequality. Pacific Northwest potlatches and elite labrets, for instance, transformed markers into symbols of rank.

The psychological engine of belonging

Moffett argues that our drive for belonging begins in infancy. Babies as young as five months prefer familiar faces and accents. By preschool, children categorize others by race and language and intuit “essences” behind group differences. Such essentialism turns social identities into seemingly natural facts, explaining why people treat nationality or ethnicity as immutable. That’s why a flag, anthem, or accent can trigger deep emotion—or disgust—far beyond rational understanding.

Cooperation’s paradox and the edges of inclusion

The very traits that let societies scale also make them fragile. Markers and rituals forge unity but can quickly harden into tools of exclusion. History abounds with tragic examples: dehumanization during genocides, internment during wartime, and suspicion toward immigrants who display unfamiliar markers. Yet Moffett remains cautiously optimistic. Humans, unlike ants, can reinterpret markers, invent inclusive symbols, and design institutions to expand belonging. Nations, he suggests, are experiments in managing that tension between cohesion and openness.

Core idea

Human societies are scalable networks of recognition built on shared identity. They endure by balancing two instincts—the pull toward belonging and the need to defend boundaries. Understanding how identity works, biologically and culturally, reveals both the source of our strength and the roots of our division.

Why can ants build seamless supercolonies while chimpanzee societies fracture at a few dozen individuals? Moffett’s answer lies in the mechanisms of recognition. Species survive by deciding who belongs and who doesn’t, and the cognitive or chemical tools they use determine the scale of belonging.

The limits of memory

Individual recognition anchors most mammalian societies. A wolf pack, elephant herd, or chimpanzee community functions because each member knows others personally. But memory has limits: Dunbar’s research suggests that humans, like other primates, can manage only around 150 active relationships. Beyond that number, cohesion breaks down—unless the species finds another way to know who belongs.

The marker revolution

Social insects solved the memory problem chemically. Argentine ants, for example, recognize colony membership by scent rather than memory. Matching hydrocarbon signatures act like a password. In humans, markers perform a similar function but with cultural symbols instead of chemistry—dress codes, dialects, rituals—that let strangers identify each other as part of the same group. This hybrid model—personal relationships plus impersonal markers—makes human societies flexible and vast.

Anonymous membership and social design

Moffett’s pithy formula captures this: “Chimpanzees need to know everybody; ants need to know nobody; humans only need to know somebody.” Because humans rely on markers rather than memory for distant relationships, we can cooperate with people we've never met—voting for a shared flag, paying taxes, or responding to disaster relief. Language and appearance provide fast identity checks that make institutions possible. The society becomes an organism without requiring all its cells to recognize one another personally.

Ant supercolonies as mirrors

Moffett uses ant empires to dramatize the consequences. Supercolonies like California’s “Large Colony” stretch for thousands of kilometers and fight brutal wars against competing colonies, guided solely by scent distinctions. Human nations parallel this phenomenon symbolically: borders, flags, and passports function as cognitive scents that mark belonging. The ant metaphor, he warns, isn’t perfect but reveals how scalable identity systems make possible both civilization and conflict.

Key takeaway

Markers are humanity’s social prosthesis—our way of stretching the limits of personal recognition to create stable, anonymous societies. They let us cooperate at scale, yet they always risk turning difference into division.

Early human life unfolded in small, egalitarian bands—flexible, mobile groups where leadership was temporary and wealth was shared. Moffett uses these bands as windows into humanity’s default social mode, the template from which all later societies grew and to which they sometimes regress.

Band societies: equality by design

A band is a mobile collective of roughly 25–35 members that splits and merges according to resources and relationships. Food sharing and mobility act as safeguards against domination. Reverse dominance—a social mechanism where the group ridicules or ostracizes bullies—maintains equality. This structure mirrors our evolutionary roots: groups small enough for face-to-face relationships and consensus-driven decision-making.

The shift to settlement

When environmental abundance allowed permanent villages (as in Pacific Northwest salmon cultures or Australia’s Mount Eccles), the equation changed. Fixed storage and reliable harvests made inequality feasible. Some individuals became specialists, leaders, or ritual authorities, wielding new forms of symbolic power. Status markers—jewelry, elaborate rituals, and potlatches—signaled both prestige and hierarchy. Settlement transformed societies from fluid neighborhoods into early chiefdoms, balancing community solidarity with emerging rank.

Leadership and specialization

Settled life requires coordination: organizing labor for construction, managing stored food, defending territory. That need fosters leadership, often charismatic and ritualized rather than purely coercive. Chiefs earned status through redistribution (as in the Calusa or Pacific Northwest), but over time status hardened into heredity. Society’s markers began to encode internal inequalities as well as group belonging.

The progression from egalitarianism to stratification wasn’t inevitable but cyclical. Some groups reverted to egalitarian norms after crises, demonstrating that hierarchy is an adaptation, not destiny. Still, once surplus and population density rise, the balance tilts toward leadership and inequality—a pattern seen repeatedly in archaeology and history.

Moffett turns from anthropology to psychology to show why identity feels so binding. The impulse to sort people into categories is not learned late in life—it’s built into you from infancy. This natural tendency shapes the power of symbols, stereotypes, and rituals in every society.

Built to recognize and divide

Infants show early preferences for familiar faces, languages, and even smells. By the first year, babies expect people speaking their language to share food or habits. These biases form the foundation for later attachments to cultural markers. Neuroscientist Uri Hasson’s findings on neural coupling show that shared stories literally synchronize brain activity—an echo of the emotional resonance you feel in a crowd singing a national anthem.

Essentialism and its consequences

Children intuitively think categories have essences—deep, unchangeable qualities. This belief makes social categories seem biological. A member of another race or nation feels “different in kind,” not just experience. Adults carry this bias into political and moral thinking, where markers like flags or uniforms trigger visceral reactions. The Holocaust survivor who faints at a swastika or the pride swelling during a national parade both stem from this essentialist wiring.

Stereotypes, stories, and memory

From personal categories grow cultural ones. Stereotypes act as memory shortcuts, letting you make instant judgments. Stories then endow them with moral and emotional force: the patriotic myth of founding heroes or the vilifying rumor about a rival group. Collectively repeated, such narratives outlast individuals. As historian Ernest Renan noted, nations are built as much on selective forgetting as on shared memory. Moffett adds that stories function like cultural DNA—transmitted, replicated, and occasionally mutated.

The psychological foundation

Because you are neurologically tuned to detect sameness and difference, group identity feels intrinsic. The task of civilization is not to erase this wiring but to channel it—through inclusive education, mixed institutions, and shared symbols that widen the circle of belonging.

Societies transform shared emotion into moral power. Through ritual, members fuse with one another, sometimes transcending self-interest, sometimes surrendering their conscience. Moffett explores how rituals create solidarity and how the same mechanisms can spiral into dehumanization and violence.

Rituals as social glue

Whether you join a baptism, a national parade, or a football chant, you participate in a collective performance that makes the group tangible. These rituals evoke entitativity—the sense of the group as a single being. The stronger the experience, the likelier members are to “fuse” their personal identity with the group’s. Anthropological examples like the Sateré-Mawé bullet-ant rite show that pain and hardship, shared publicly, amplify this bond.

The double edge of identity fusion

Fusion strengthens trust and sacrifice (think of soldiers protecting comrades) but also weakens personal moral brakes. Crowds can act as organisms of collective will, committing atrocities without individual intent. Historical spectacles—from Nuremberg rallies to mass pilgrimages—demonstrate the same chemistry of emotion, rhythm, and submission that unites but can also destroy.

From ranking to dehumanization

Relatedly, every society builds hierarchies of worth. Many hunter-gatherer names translate to “the real people,” signaling outsiders as lesser. Psychologists find that humans map social perception along two axes—warmth and competence—and that those seen as lacking both evoke disgust rather than empathy. Disgust dehumanizes, leading to moral collapse: the same cognitive shortcuts that once helped early societies guard themselves now enable modern hate propaganda.

The line between unifying ritual and dehumanizing ideology is one of intent and context. Healthy communities institutionalize compassion and renewal (religious confession, civic service); pathological ones sanctify purity and fear. Your capacity for empathy must therefore be deliberately maintained—it is not the default once collective emotion takes over.

Having shown how small groups cohere, Moffett asks how they expand. Conquest, slavery, and assimilation, not just voluntary union, forged the vast societies we know today. The history of nations is the story of how diverse peoples were welded—sometimes violently—into shared symbolic systems.

From agriculture to empire

The Neolithic surplus allowed some communities to support bureaucracies and armies. Circumscribed environments like the Nile Valley encouraged domination rather than flight, giving birth to states. Slavery and tribute turned conquest into integration: captured artisans in Rome, enslaved craftspeople in the Pacific Northwest, or laborers in Mesoamerica became essential to expansion. These systems incorporated outsiders through work, ritual, and gradual assimilation.

Asymmetrical assimilation

Every expanding society faces a founder’s dilemma: the dominant group sets the symbols and language others must adopt. The Inca ruled through local elites; Rome assimilated provinces via citizenship; China absorbed non-Han peoples through centuries of cultural translation. Assimilation thus means addition without equality—the borrowed identity remains marked.

Immigration and modern identity

Modern nations replaced coercive assimilation with legal integration. Immigration, from Jefferson’s era to the current global movement, creates constant negotiation between openness and anxiety. Institutions like the U.S. oath of citizenship or the European Union’s shared values attempt to forge a superordinate identity. Yet Brexit and ethnic nationalism remind us that ancient instincts still resist large-scale unity.

Lesson from empire

Societies grow by incorporating others, but they endure by inventing inclusive symbols. The test of any civilization is whether it can transform subjugation into solidarity and diversity into belonging.

In a globalized, interconnected world, Moffett ends by returning to the core question: Can societies persist without new enemies? He argues that identity always requires boundaries, but those boundaries can be symbolic rather than violent—redrawn through civic patriotism, diversity, and shared purpose.

Patriotism vs nationalism

Patriotism expresses care for fellow members; nationalism seeks dominance of the group identity. Both spring from the same root need for belonging, but they diverge in how they treat outsiders. Patriots reform from within; nationalists police symbols and purity. The Olympic outrage over gymnast Gabby Douglas forgetting to place her hand on her heart captures this difference—symbolic conformity became a test of loyalty.

Scapegoats and social autoimmunity

Fear or crisis often turns identity inward. When one member of a perceived minority acts violently, entire groups can be blamed—as after the 2016 Pulse nightclub shooting versus the individualized treatment of Timothy McVeigh. Societies under stress attack their own tissues like autoimmune diseases, confusing protection with purification. History’s persecutions, from witch hunts to internment camps, follow this reflex.

Designing inclusive identities

Moffett concludes that you cannot eliminate identity politics because identity is the framework of society itself. The challenge is to create overlapping circles of belonging: civic institutions, shared rituals, and laws that reward cooperation across lines. Switzerland’s federal cantons and the Tukanoan intermarriage system offer functional analogs—arrangements that preserve difference while reinforcing unity.

Ultimately, societies live and die by their ability to update markers—to revise who “we” are. Nations that freeze identity risk decline; those that adapt may survive the need for enemies. As Chief Seattle warned in the 1850s, “Societies come and go like waves.” What endures is not any particular flag but the human capacity to imagine belonging anew.