In his book Tipping Point, Malcolm Gladwell carefully works his way through British anthropologist Robin Dunbar’s research on the limits of human relational connections, which has come to be known as “Dunbar’s number.”
Dunbar has actually developed an equation, which works for most primates, in which he plugs in what he calls the neocortex ratio of a particular species – the size of the neocortex relative to the size of the brain – and the equation spits out the expected maximum group size of the animal. If you plug in the neocortex ratio of Homo sapiens, you get a group estimate of 147.8 or roughly 150. “The figure of 150 seems to represent the maximum number of individuals with whom we can have a genuinely social relationship, the kind of relationship that goes with knowing who they are and how they relate to us. Putting it another way, it’s the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar” . . . Then there is the example of the religious group known as the Hutterites, who for hundreds of years have lived in self-sufficient agricultural colonies in Europe and, since the early twentieth century, in North America. The Hutterites (who came out of the same tradition as the Amish and the Mennonites) have a strict policy that every time a colony approaches 150, they split it in two and start a new one. “Keeping things under 150 just seems to be the best and most efficient way to manage a group of people,” Bill Gross, one of the leaders of a Hutterite colony outside Spokane told me. “When things get larger than that, people become strangers to one another.” The Hutterites, obviously, didn’t get this idea from contemporary evolutionary psychology. They’ve been following the 150 rule for centuries. But their rationale fits perfectly with Dunbar’s thesis. At 150, the Hutterites believe, something happens – something indefinable but very real – that somehow changes the nature of community overnight. “In smaller groups people are a lot closer, They’re knit together, which is very important if you want to be effective and successful at community life,” Gross said. “If you get too large, you don’t have enough work in common. You don’t have enough things in common, and then you start to become strangers and that close-knit fellowship starts to get lost” . . . If we want groups to serve as incubators for contagious messages, then . . . we have to keep groups below the 150 Tipping Point. Above that point, there begin to be structural impediments to the ability of the group to agree and act with one voice . . . The Rule of 150 says that congregants of a rapidly expanding church, or the members of a social club, or anyone in a group activity banking on the epidemic spread of shared ideals needs to be practically cognizant of the perils of bigness.
I read Gladwell’s work over ten years ago as I began the hard work of planting a new church with the desire to, as Gladwell says, “serve as incubators for contagious messages” and bank “on the epidemic spread of shared ideals.” I even underlined the entire passage I’ve posted in this blog, but everything in North American church culture suggested to me, “Yeah this is interesting information but let’s get real here – bigger is really better.” It’s taken me ten years to circle back and realize, out of my own hard experiences, that this Rule of 150 is actually very real and very meaningful. It is what informs our own church’s commitment to not add a second service – ever – and when we get to the bounds of 150 to keep planting churches and missions throughout our city. I personally think that if more churches functioned like the Hutterites referenced by Gladwell, and simply had a way of life that believed, “At 150 we always move to launch a new community” the wider church in North America would be far better at serving “as incubators for contagious messages” – which for us is nothing less than the spread of the Gospel and the transformation of our cities as a result of spreading that Gospel. If this resonates with you, share this post with your church and your pastor.