Many of us will recall Petri dishes from our first biology class – those shallow glass vessels containing a nutrient gel into which a microbe sample is injected. In this sea of nutrients, the cells grow and multiply, allowing the colony to flourish, its cells dividing again and again. But just as interesting is how these cells die. Cell death in a colony occurs in two ways, essentially. One is through an active process of programmed elimination; in this so-called ‘apoptotic’ death, cells die across the colony, ‘sacrificing’ themselves in an apparent attempt to keep the colony going. Though the mechanisms underlying apoptotic death are not well understood, it’s clear that some cells benefit from the local nutrient deposits of dying cells in their midst, while others seek nutrition at the colony’s edges. The other kind of colony cell death is the result of nutrient depletion – a death induced by the impact of decreased resources on the structure of the waning colony.
Both kinds of cell death have social parallels in the human world, but the second type is less often studied, because any colony’s focus is on sustainable development; and because a colony is disarmed in a crisis by suddenly having to focus on hoarding resources. At such times, the cells in a colony huddle together at the centre to preserve energy (they even develop protective spores to conserve heat). While individual cells at the centre slow down, become less mobile and eventually die – not from any outside threat, but from their own dynamic decline – life at the edges of such colonies remains, by contrast, dynamic. Are such peripheral cells seeking nourishment, or perhaps, in desperation, an alternative means to live?
But how far can we really push this metaphor: are human societies the same? As they age under confinement, do they become less resilient? Do they slow down as resources dwindle, and develop their own kinds of protective ‘spores’? And do these patterns of dying occur because we’ve built our social networks – like cells growing together with sufficient nutrients – on the naive notion that resources are guaranteed and infinite? Finally, do human colonies on the wane also become increasingly less capable of differentiation? We know that, when human societies feel threatened, they protect themselves: they zero in on short-term gains, even at the cost of their long-term futures. And they scale up their ‘inclusion criteria’. They value sameness over difference; stasis over change; and they privilege selfish advantage over civic sacrifice.
Viewed this way, the comparison seems compelling. In crisis, the colony introverts; collapsing inwards as inequalities escalate and there’s not enough to go around. In a crisis, as we’ve seen during the COVID-19 pandemic, people define ‘culture’ more aggressively, looking for alliances in the very places where they can invest their threatened social trust; for the centre is threatened and perhaps ‘cannot hold’.
Human cultures, like cell cultures, are not steady states. They can have split purposes as their expanding and contracting concepts of insiders and outsiders shift, depending on levels of trust, and on the relationship between available resources and how many people need them. Trust, in other words, is not only related to moral engagement, or the health of a moral economy. It’s also dependent on the dynamics of sharing, and the relationship of sharing practices to group size – this last being a subject that fascinates anthropologists.
In recent years, there’s been growing attention to what drives group size – and what the implications are for how we build alliances, how we see ourselves and others, and who ‘belongs’ and who doesn’t. Of course, with the advent of social media, our understanding of what a group is has fundamentally changed.
The British anthropologist Robin Dunbar popularised the question of group size in his
book How Many Friends Does One Person Need? (2010). In that study, he took on the challenge of relating the question of group size to our understanding of social relationships. His interest was based on his early studies of group behaviour in animal primates, and his comparison of group sizes among tribal clans. Dunbar realised that, in groups of more than 150 people, clans tend to split. Averaging sizes of some 20 clan groups, he arrived at 153 members as their generalised limit.
However, as we all know, ‘sympathy groups’ (those built on meaningful relationships and emotional connections) are much smaller. Studies of grieving, for example, show that our number of deep relationships (as measured by extended grieving following the death of a sympathy group member) reach their upward limit at around 15 people, though others see that number as even smaller at 10, while others, still, focus on close support groups that average around five people.
For Dunbar, 150 is the optimal size of a personal network (even if Facebook thinks we have more like 500 ‘friends’), while management specialists think that this number represents the higher limits of cooperation. In tribal contexts, where agrarian or hunting skills might be distributed across a small population, the limiting number is taken to indicate the point after which hierarchy and specialisation emerge. Indeed, military units, small egalitarian companies and innovative think-tanks seem to top out somewhere between 150 and 200 people, depending on the strength of shared conventional understandings.
Though it’s tempting to think that 150 represents both the limits of what our brains can accommodate in assuring common purpose, and the place where complexity emerges, the truth is different; for the actual size of a group successfully working together is, it turns out, less important than our being aware of what those around us are doing. In other words, 150 might be an artefact of social agreement and trust, rather than a biologically determined structural management goal, as Dunbar and so many others think. We know this because it’s the limit after which hierarchy develops in already well-ordered contexts. But we also know this because of the way that group size shrinks radically in the absence of social trust. When people aren’t confident about what proximate others are mutually engaged in, the relevant question quickly turns from numbers of people in a functioning network to numbers of potential relationships in a group. So, while 153 people might constitute a maximum ideal clan size, based on brain capacity, 153 relationships exist in a much smaller group – in fact, 153 relationships
exist exactly among only 18 people.
Dunbar’s number should actually be 18, since, under stress, the quality of your relationships matters much more than the number of people in your network. The real question is not how many friends a person can have, but how many people with unknown ideas can be put together and manage themselves in creating a common purpose, bolstered by social rules or cultures of practice (such as the need to live or work together). Once considered this way, anyone can understand why certain small elite groups devoted to creative thinking are sized so similarly.
Take small North American colleges. Increasingly, they vie with big-name universities such as Harvard and Stanford not only because they’re considered safer environments by worried parents, but because their smaller size facilitates growing trust among strangers, making for better educational experiences. Their smaller size matters. Plus, it’s no accident that the best of these colleges on average have about 150 teaching staff (Dunbar’s number) and that (as any teacher will know) a seminar in which you expect everyone to talk tops out at around 18 people.
But what do we learn from these facts? Well, we can learn quite a bit. While charismatic speakers can wow a crowd, even the most gifted seminar leader will tell you that his or her ability to involve everyone starts to come undone as you approach 20 people. And if any of those people require special attention (or can’t tolerate ideological uncertainty) that number will quickly shrink.
In the end, therefore, what matters much more than group size is social integration and social trust. As for Facebook’s or Dunbar’s question of how many ‘friends’ we can manage, the real question ought to be: how healthy is the Petri dish? To determine this, we need to assess not how strong are the dish’s bastions (an indicator of what it fears) but its ability, as with the small North American college, to engage productively and creatively in extroverted risk. And that’s a question that some other cultures have embraced much better than even North American colleges.
Image: Fiddlesticks Country Club, a gated community in Fort Meyers, Florida. Photo by Michael Siluk/UIG/Getty
