The British evolutionary psychologist Robin Dunbar (born 1947) is best known for ‘Dunbar’s number’, his estimate that humans can keep up about 150 meaningful relationships, roughly the size at which hunter-gatherer communities tended to split. In How Religion Evolved (2022) he says that the oldest religion was shamanic, a religion of direct, trance-based experience that bonded communities of about that size, and that gods, priests and doctrine were added later, once people settled in large villages. Therapeutic Shamanism uses Dunbar’s number for the natural scale of a healthy tribe, and meets his account of religion on several points whilst reading the later layers differently.
Who is Robin Dunbar? #
A British biological anthropologist and evolutionary psychologist, born in Liverpool in 1947, whose specialism is primate behaviour. He is professor emeritus of evolutionary psychology at the University of Oxford and a Fellow of the British Academy.1 His books include Grooming, Gossip and the Evolution of Language (1996), How Many Friends Does One Person Need? (2010), Friends (2021) and How Religion Evolved: And Why It Endures (2022). The idea that made his name came from a 1992 paper comparing brain size with group size across monkeys and apes.
What is Dunbar’s number? #
The size of community the human brain seems built for, about 150 people. Primatologists had noticed that monkeys and apes live in tight-knit grooming groups whose size is not random but tracks the size of the neocortex, the outer layer of the brain. In 1992 Dunbar used that relationship to predict the average group size of dozens of species of monkeys and apes, then applied the same reasoning to humans and arrived at about 150, with a much smaller inner circle. Tested against what is known of hunter-gatherer cultures, his prediction was mostly borne out.2
He has since filled the picture out. Our relationships come in layers, each about three times the size of the one inside it: about five intimates, fifteen close friends, fifty good friends, 150 meaningful relationships, then 500 acquaintances and 1,500 people whose faces we can put a name to. Time and care are rationed by layer, and a friendship that is not kept up slips outwards.3 In hunter-gatherer life he places camp groups of thirty to fifty people inside communities of about 150, which are in effect extended families. The same number turns up in very different places. Hutterite colonies, farming religious communities in North America, split when they reach about 150 to 165 members, and congregations tend to settle at about that size or to divide.3 So the number is not a limit on how many people we can meet, but on how many we can know as people, in the way members of a tribe know each other.
For how Therapeutic Shamanism uses the number in its teaching on tribe, see What do tribe and belonging mean, and what is the shaman’s role in a community?
Why does the size of a tribe matter? #
Because a group much bigger than about 150 becomes stressful, and humans have spent most of their history in groups small enough not to be. Hunter-gatherer tribes generally ranged from about twenty people up to an optimal maximum of around 150, and once they grew past about two hundred they tended to split into smaller tribes.4 Groups of fewer than about twenty were rarely viable for long, since hunting and gathering, and caring for children whilst others hunted, needs enough people to cooperate.
The trouble began when we stopped splitting. With farming, people began to live in settlements of thousands, then cities of hundreds of thousands and millions, amongst strangers, which we are not wired for. Managing such numbers needed much more complex social structures: rules and regulations, laws and contracts, and in time police forces and prisons, to contain stresses and conflicts that small, well-known groups rarely produced.5 In this sense Dunbar’s number is part of the story of domesticationDomestication. The process by which, in domesticating other species, we domesticated ourselves. When dated precisely, Domestication begins with the Neolithic era, before the Fall proper, which begins with the first city-state cultures around 4000 BCE. What rewilding works to undo. More about this, since the larger human settlements became, the more people had to be tamed to fit them. See Are humans a self-domesticated species? and What makes a healthy group or tribe?
What does Dunbar say about how religion evolved? #
That religion began as a shared experience, not as a belief system. Its root, in his account, is what he calls the ‘mystical stance’: a capacity for trance, a sense of a spirit world, and a belief that hidden powers can be called on. He thinks it very ancient, “part of what it is to be human”.6 The oldest religions were, in his words, ‘immersive’ or ‘shamanic’, religions of direct experience, often of trance brought on by music and dance, with no priests, temples or written doctrine. The San of the Kalahari, hunter-gatherers whose trance dance he describes, called a dance whenever relations in the camp had frayed.6
Their main work, he argues, was bonding a community. Singing, dancing, moving in time together, feasting and telling emotional stories all release endorphins, the brain’s own opiates, which leave people calmer and more trusting of each other. In his experiments, rowing in time with others doubled the effect of rowing alone, and in a set of naturalistic groups, a drumming circle amongst them, moving in synchrony went with a stronger sense of belonging and of the sacred.7 This bonding works best at about the size of a natural community, which is why he connects religion so closely with his number.
Doctrinal religion, with gods, priests, temples, theologies and moral codes, came later. Dunbar places it in the Neolithic, when people began settling in villages, which he thinks they did first for defence against raiders, and then had to find ways of holding large, stressed communities together. Gods who watch and punish human morals arrived later still, once societies grew to around a million people.8 In his summary, the history of religion is not one form replacing another but the accretion of new layers around an older core. The old shamanic layer never disappears, and it still gives every doctrinal religion its emotional pull.9
Was animism there before shamanism? #
On the evidence Dunbar reports, yes. He draws on a study of thirty-three hunter-gatherer societies which found animism to be the oldest religious trait, present in all of them, with shamanism, belief in an afterlife and ancestor worship arriving later as a group. Dunbar adds that interfering high gods are very rare amongst hunter-gatherers and go with farming and herding.10 He also writes that trance on its own does not mean there were shamans, since in his wider sense shamanism is spirit travel in trance that many people may do without special training, and in his narrower sense it is the specialist healer.
That fits the way Therapeutic Shamanism places the two. Shamanism is part of a wider spiritual practice, animism, in which everything is alive and conscious and humans are one of the Animal People amongst the Plant and Stone PeopleStone People. All physical matter: mountains, sea, rivers, clouds, sun and stars: the oldest and widest of the Peoples. As some animist cultures put it, ‘we are just the Stone People, dancing for a while’. Read the full answer. Shamans are people who can, in addition, go into trance at will and travel the shamanic realms. Where exactly the dividing line falls depends on how trance is defined, and it is far from settled.11 See What is animism?
Where does Dunbar’s account meet Therapeutic Shamanism, and where does it part from it? #
It meets it on the order of things. Hunter-gatherer cultures generally took little interest in gods and goddesses; almost as soon as the first city-states appear, so do stories of meddling, wrathful gods who demand worship, temples and sacrifice.12 Possession, too, is generally found only in agricultural and stratified societies, not amongst hunter-gatherers, as the anthropologists Michael Winkelman, Erika Bourguignon and Thomas Evascu have found.13 And the first organised religions were, whatever else they were, agents of further domestication and control, teaching people not to trust their own bodies, instincts or souls.14 Dunbar’s layers run the same way, with an old, experiential, community religion, and priests, temples and moral gods laid on top once people lived in large settled groups. His dating agrees too, since in Therapeutic Shamanism the break from animism begins with domestication and the Neolithic and accelerates with the FallThe Fall. The catastrophe at the root of the whole diagnosis: the shift from animist, egalitarian hunter-gatherer life to owning, agricultural Taker culture. In domesticating other species we domesticated ourselves, cutting ourselves off from Mother Earth (Power-loss) and from parts of our own nature (soul-loss). When dated precisely, the Fall begins with the first city-state cultures, around 4000 BCE (Domestication begins earlier, with the Neolithic). A sickness, not our true nature. ‘Fallen culture’ is used interchangeably with Taker culture; the Great Rupture is a looser alternate name. Read the full answer and the first city-states around 4000 BCE. See What is the Fall?
It parts from it on what the layers mean. Dunbar writes as an evolutionary psychologist, explaining religion by what it does, through brains, endorphins and the strains of living in groups, and he sets out to judge no religion true or false. Therapeutic Shamanism does not treat the spirit world as a product of the brain; journeying is an experience to be tried for oneself, and the PeoplesThe Peoples. The Animal People, Plant People, Standing People (the Trees) and Stone People: our elder kin, of whom the Human People are the youngest and least wise. A family, not a hierarchy. Read the full answer met there are real. Where Dunbar reads doctrinal religion as machinery for holding large, stressed communities together, Therapeutic Shamanism reads the meddling gods as something else, not real Upper-WorldUpper-World. The realm of Father Sky and of Spirit: spacious, rarefied and clear, layered in tiers, offering not escape but perspective. Not better than the Lower-World: we ascend rooted, and bring the gifts back down. Read the full answer beings at all, but our collective demons, repressed energies from the human collective unconscious.12 And whereas hunter-gatherer life was, in Therapeutic Shamanism’s account, far less conflict-ridden than ours because strangers were rarely met, Dunbar writes that prehistoric life was not idyllic and that violent death rose with the size of the living group; both tie conflict to the strain of living too close to too many people. See Is Therapeutic Shamanism a religion or belief system?
Is Dunbar’s number disputed? #
Yes. In 2021 the biologists Patrik Lindenfors, Andreas Wartel and Johan Lind, of Stockholm University, re-ran the comparison of brain and group size with newer data and methods in Biology Letters. Their estimates for the largest human group ranged so widely, from about two to about 520 people, that they concluded that no figure for humans could be estimated with any precision by that route.15
Dunbar replied in a technical comment that they had used the wrong statistical method and should have compared humans with the apes alone, and in a reply article wrote that his number has withstood thirty years of scrutiny; he also points to some two dozen separate studies, of hunter-gatherer communities, villages, armies, Christmas card lists and online networks, whose averages cluster around 150.16 The Stockholm group, in turn, say their conclusion holds whichever method is used. The argument is about how precisely a number can be worked out from brain size, more than about whether small, well-known groups suit humans best, which the hunter-gatherer evidence supports either way.
Does it mean we can only have 150 friends? #
Not quite. Dunbar’s 150 is the layer of people we know as people and keep up a real relationship with, not a ceiling on acquaintances, and inside it the circles of close friends and intimates are much smaller. For wellbeing, how good those relationships are matters more than how many there are. Therapeutic Shamanism adds that hunter-gatherers did not meet their need for company from humans alone, and that much of our loneliness now comes from losing our relationships with the other-than-human. See Why are we so lonely, and what is the difference between loneliness and Solitude?
