The Church and Dunbar’s Number

The Church and Dunbar’s Number

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How large should your church be?

Silly question, you say. Depending on your theology or worldview, you might add:

* Large as possible! Bigger is better!

* That’s up to God!

* I’m shooting for 1,000 (or 2,000, or 3,000, or whatever).

* I like small and intimate!

Here’s a better answer: A congregation should be large enough to fulfill all the essential functions of Christ’s body—and small enough to really function as body of Christ.

So we might take a quick look at “Dunbar’s Number,” which happens to be 150.

I believe (as I have written in Liberating the Church and elsewhere) that the three essential functions of the body of Christ, biblically speaking, are worship, community, and witness. The New Testament speaks much about all three. And importantly, all three of these key body-life dynamics are social as well as spiritual. (Biblically speaking, of course, all spirituality is social, as John Wesley saw so well.)

Since all church life is social, it necessarily involves social dynamics—the ways groups and personal relationships function. It would be a mistake to think that “laws” govern social behavior. But certainly social behavior is influenced and constrained by numerous limiting factors. It’s hard to squeeze 100 students into a classroom that seats 25. On the other hand, the dynamics of a class of 25 will be much different in a room that seats 500 rather than one of more appropriate size.

Many other things besides architecture shape our social dynamics. Language. Gender. Age. Dress. Ethnicity. Available time. Wealth and poverty. Behavioral customs. New Testament writers often address such issues (James on wealth and poverty; Paul on food and dress, for instance).

Congregational size is however one key factor that shapes congregational behavior. Which means there is a connection between congregational size and discipleship.

What is Dunbar’s Number?

Robin Dunbar (b. 1947), an anthropologist and evolutionary psychologist at the University of Oxford, is the guru behind Dunbar’s Number. Studying both animal and human organizational behavior—including brain function—Dunbar concluded that there is a “cognitive limit to the number of individuals with whom any one person can maintain stable relationships,” and that that limit is 150 persons. Turns out 150 is the maximum number of people that one person can have meaningful ongoing relationship with.

Dunbar speaks of a cognitive limit in social relationships. In other words, physiological/neurological factors are involved. Our brains are wired this way. Our neural capacity is not infinite, and so the potential number of significant social relationships is not infinite. What might perhaps be true spiritually, in some extra-physical sense, is another question.

Dunbar’s Number is appealing because it’s so simple and neat and round. One hundred fifty! Can things really be that simple? No. But is Dunbar onto something? Yes. Could this be important for the church? Possibly. I take the number with a grain of salt and some good gospel light. It is worth pondering.

So Dunbar’s Number is the maximum number of folks you can know personally (not just by name or sight), and who know you. The largest number you can comfortably maintain stable relationships with. No name tags needed. If we’re talking about a congregation or other cohesive group, that would mean not only the people you know who know you. It would also mean these people all know each other in a functionally significant way.

“Functionally significant” is fuzzy, of course. But the fuzziness allows room for the ever-present messiness and changing dynamics of a social group. Relational dynamics are never neat and clear, unless rigidly controlled. And in that case, we’re no longer speaking of real community.

In groups larger than 150 or so, explicit rules and regulations are needed in order to maintain group cohesion. Thus, more formality; less informality. In Christian terms, relationships based less on koinonia and more on explicit organizational requirements.

Makes Some Sense

To me, Dunbar’s Number makes some suggestive sense. I say this for four reasons.

First, Dunbar’s Number checks generally with my experience of congregations in my own and other denominations, and in various countries. The most vital congregations I have experienced ranged in size between about 70 and 200. Perhaps 150 is a good average. (I have visited “successful” churches that were many times larger, but most felt more like shopping malls than communities—though some had more intimate infrastructures.)

Second, church history shows a parallel pattern. As I have observed elsewhere, dynamic church movements grow by multiplying fairly small units rather than by growing ever larger ones. When denominations or other religious movements grow significantly, they multiply small congregations that develop into medium-sized ones and then spin off new ones. Declining overall growth (or rate of growth) correlates with larger and larger but less internally dynamic congregations.

Methodism in North America is the classic example. But there are many others through history. We find a similar pattern in various kinds of movements, in fact, not just in the church. There is a large literature on this, and I’ve written some on it myself.

It would be stupid of course to think that congregational size, or Dunbar’s Number, is the only factor. All groups have an ecology to them, which means multiple interacting factors. What is cause and what is effect is often unclear. My point is simply that church history does seem to bear out the possible dynamics behind Dunbar’s Number.

Third, past research into interpersonal relationships and group size points in the same direction. Some years ago I discovered suggestive research positing natural thresholds in human social relationships at roughly three levels: three people, 12 people, and (as I recall) around 150.

Of course a lot of literature points to the importance of groups of 12. No surprise then that Jesus chose 12 apostles, had a more intimate group of three, and that beyond the 12 a much larger somewhat amorphous group of disciples followed Jesus. After Pentecost, Jesus’ many disciples metamorphosed into a cohesive and growing network of home fellowships, as we see in Acts. Vital churches today often mirror these dynamics in their social ecology.

Fourth, Dunbar’s Number (as a tendency, not a tight rule) is consistent with the nature of ecology and of ecosystems generally. This is how living things grow: By cell growth, division, and ongoing growth, constantly renewing life. There is a normal, healthy rhythm and pattern. Small things are born and develop. But they grow not by getting ever bigger, but by reproducing themselves when they reach a certain level of maturity. Strange that we should think it would be any different with the church!

Here’s the Point

Spiritual and social dynamics on earth are subject to limits built into the creation, including the human creation. These are not “laws” forced upon us. Rather they reflect the nature of creation from the hand of God. They are dynamics which can help us, or which we can ignore to our own hurt.

This has implications at many levels of church life, including discipleship. Here however I’m focusing specifically on congregational size. This is what I see:

God never made us to experience Christian community in congregations of 1,000 or so. Even 500 is often very unhealthy in terms of discipleship and real koinonia. It seems that 125 to 175 is a good healthy number, and 150–200 generally provides a good basis for spinning off daughter or sister congregations. (This depends of course on the spiritual health of the congregation. An unhealthy or dysfunctional congregation will birth congregations that are similarly dysfunctional.)

More basically: Something important happens to community, to koinonia, when congregations grow beyond 150 or so. How many times have I heard versions of this: “We seemed to lose something as we grew larger.” Of course! Genuine community requires proximity, interaction, practice of the New Testament “one-anothers,” mutual encouragement and correction (Heb 3:13, 10:24-25). This is not optional if disciple-making, not just larger congregations, is the goal.

Granted, larger congregations provide “economies of scale” which may permit more programs, staff, or facilities. But such “advancements” are not necessarily a good thing. Especially if the tradeoff is shallower community or weakened discipleship. Such changes may actually hasten a church’s accommodation to the prevailing culture. It is a familiar pattern.

In this connection, you might reflect on your own experience of church over time.

So, consider Dunbar’s Number. I emphasize again: This is a suggestive observation, possibly based partly in physical/neurological factors, not a rigid rule. There are no hard and fast breakpoints in social relationships. But there are thresholds. I think the thresholds are very real, based in part on the way we are created (including neurologically) in the image of God, mixed in with a range of cultural factors. The thresholds are real, but precise numbers may vary for a range of reasons. They reflect the social-spiritual-physical-cultural ecology of our life on earth.

I close by rephrasing my introductory observation: A congregation should be large enough to fulfill all the essential ecological functions of Christ’s body—and small enough to really function ecologically as Christ’s body.


Dunbar’s Number has been discussed in business circles, and Malcolm Gladwell talks about it in The Tipping Point. Wikipedia has an article on it. See:

I discuss congregational size briefly in Community of the King, Chapter 8, and in Decoding the Church, Chapter 4.


6 Responses

  1. Thanks for the article, which a friend shared on Facebook! I’ve greatly enjoyed your work over the years, especially Community of the King. So, as a fan, may I push back a little on this?

    Basically Dunbar suggested a correlation between the size of brains in primates and the social groups they form –
    essentially, the larger the brain, the larger the social circle. He then predicted that humans could (based on brain size) have no more than about 150 people in their social circle.

    A few years ago he developed his thesis further by adding what he called Dunbar’s Layers, which tried to take into account the quality (or emotional closeness) of our relationships. His primary evidence came from a study of 6 billion phone calls made by 35 million people in an unnamed European country in 2007, and assumed that frequency of calls indicated the strength of their relationship. (The calls had to be reciprocal to screen out business, spam and casual calls!) His conclusion was that people had layers of relationships, moving (from closest to largest) a group of about 5, then 11, then 30, then 129 people.

    What I found interesting is that this ties more closely with the sociological work of Edward T Hall’s ‘Proxemics’, which finds that humans gather in 4 difference sizes of group: the Public context (groups in the 100s, where you connect around a shared resource), the Social context (20-70 people, where in a highly interactive environment you reveal snapshots of who you are, in order to build bonds of affinity – think extended family, or tribe), Personal context (4-12 people, where you share private thoughts and feelings), and the Transparent context (2-4 people, where you are the most open and vulnerable in your interactions).

    From a Christian perspective, I believe that God can disciple us in each of these different contexts, or sizes of gathering, but different aspects of disciple-making will particularly come to the fore in each context. Joseph Myers wrote convincingly about this in The Search to Belong, noting that we can belong in each group size in churches, just in different ways. To Hall’s groups I would also add a 5th, the Divine context, where we are alone with God our creator and redeemer (obviously vital to our journey of discipleship!).

    I think the weakness of your article is that it seems to come close to simply conflating discipleship into forming community (koinonia). Whilst the latter is a vital part of the former, it is not the only thing that needs to happen within our disciple-making. Put positively, we do desperately need forms of church life that create authentic community, but that is not the only goal we need to have in mind, and thus it should not be the primary measure that we use in every context.

    Instead, I would suggest that we need to recognize that different sizes of gathering do different things well. For instance, coming to a Sunday service and expecting intimacy with others (i.e. being free and able to share your closely guarded secrets) is plainly unrealistic – that’s not what it’s set up to do well. Yet you do need a place to do that – most healthily, I would suggest, in a triad or with an accountability partner. However, that Transparent context is not really going to do a great job of (for instance) being an open-edged space that is easy to invite friends into (i.e. it’s not great at community forming!), or, to pick another example, being a place where proclamation (usually in the form of preaching) can occur.

    Thus I think we need to see the power of growing closer to Christ in all different sizes of gathering, recognizing that they each do different (yet overlapping) things well. This also means that each context does some other vital things not very well.

    And with regards to overall church size, I would suggest that we can simultaneously grow larger and smaller at the same time. This allows the Public context expressions of church life to keep growing if that is the Lord’s will, while also multiplying the number of expressions of church life in the other contexts. Of course, this is not easy to pull off – and your piece makes some excellent comments about that – but I think we should beware artificially capping the size of a healthy church, if it has worked out how to operate in each of the strengths of each of the 5 Contexts where God disciples us, and calls us to disciple others.

    Hope this helps the conversation!

    1. That’s very interesting and informative. Thanks, Alex.

      I thought Dunbar’s thesis was interesting, but I don’t endorse it. It is more evidence of the way people relate differently to different-sized groups.

      Certainly I am not equating discipleship with koinonia! See my review of Alan Kreider’s “Patient Ferment of the Early Church” on Seedbed.


  2. Just stumbled over this, so interesting.
    Not sure if this get’s seen, but: If 150 is the limit for koinonia, how come in acts 2:44 there is total koinonia in a group of 3000+ people? it even seems the fellowship get’s better when they get to the 5000+ in the 4th chapter.

    1. Thanks! Churches can of course grow to any size, but the larger they get, the less sense of community and intimacy they have — and so they need to develop small groups of a dozen or so, and perhaps larger congregations or sub-congregations of (say) 75 to 150, in order not to lose the vital New Testament sense of community and “one anotherness.”

      Over and over I have seen it happen that a church grows into the hundreds, or perhaps into the thousands, and begins to realize that it is losing spiritual vitality for lack of more intimate face-to-face community. I discuss this in COMMUNITY OF THE KING, PROBLEM OF WINESKINS, and some of my other books.

  3. I’ve been drawn into Dunbar’s Number for some of my own research in recent years, due in part to how robust the accumulated research is. The brain simply doesn’t allow us to keep track of people and care about them beyond certain capacities. So the social science methods seem to center around the frequency of contact and the degree of caring for and from the other person. In a recent project I led among youth ministries in a city, we were able to identify four distinct patterns among the 2,000+ relationships young people identified as the 15 closest people in their lives. We were hunting qualities of support for following Jesus among their relational environment; persons’ top 15 have been shown to represent 60% of all their social interaction. Poking into these relationships, presuming that they carry more influential heft (a force for or against discipleship), was eye-opening. It seems like I’ve bought into Dunbar’s work a bit more than you, Dr Snyder…but not without sharing your fascination for what these implications mean for our formation as Christ-followers. Thanks for writing this.

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