Dunbar’s Number

150 membersHave you ever heard of “Dunbar’s Number”? Discovered by British evolutionary anthropologist Robin Dunbar, it is the human norm that the number of genuinely personal relationships a person can actively maintain is 150, give or take. Dunbar and his colleagues note that “150 people is both the approximate size of a typical small-scale human village and about the number of people who can live or work together without needing power structures to enforce cooperation. The group is small enough that social pressures can keep people in line” (“Does Your Pastor Need a Friend?” Christianity Today, October 2017, p. 62).

I find this interesting because at a recent conference I attended, the keynote speaker said that currently a majority of congregations in America have an average weekly attendance of guess what? 150 members.

It occurs to me that this is not simply a coincidence. 150 appears to be the sweet spot for most churches for the very reasons that research for Dumbar’s Number indicates:

It keeps the group manageable. People do not become just a number. People know them by name. Functions can happen without an overflow of people and not in an oversize room.

It keeps the group personal. Everybody knows each other and can keep relationships functioning. People care about one another because they know them well and see them often.

It keeps the group accountable. People notice when others are missing and can follow up with them. People can see when fellow members are straying and can bring them back into the fold. There is a sense that people are expected to be present at certain times and be there for one another in times of need.

Of course, the drawback of keeping churches at Dundar’s Number is that it causes a sense of comfort and develops into a somewhat closed community in which a congregation becomes averse to or unwilling to grow.

The goal of the Church is not be an exclusive country club, but to continue to grow. The early Church did not keep to themselves. They branched out and traveled to far-flung nations to build churches there.

My thought for today is that for those of us who are in 150-member congregations, keep up the good work of deepening relationships with one another, but at the same time look for ways to expand and grow so that bonds established here may be replicated over and over again in more and more places.

As St. Paul told an early small congregation: “We ought always to thank God for you, brothers and sisters, and rightly so, because your faith is growing more and more, and the love all of you have for one another is increasing” (2 Thessalonians 1:3). Let the increase of faith and love continue in many and various ways!


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