Switched.com carried out an interesting experiment in light of the re-release of Dunbar’s famous study on social circles.
Robin Dunbar of Oxford University demonstrated that the human brain can only comprehend a social circle of about 150 people. He tested that theory again in light of the Facebook phenomenon and concluded that the number held.
Switched performed a test using one person to see if it held up and it (pretty much) did. (A larger sample would, obviously be necessary to be more conclusive.)
What does this have to do with church, you ask?
According to church growth expert Gary McIntosh, 75% of churches in the US number 149 people or less (One Size Doesn’t Fit All, 17). I don’t think that’s a coincidence. Many people like to go to a small church because they like to know everyone and want everyone to know them. They want to “fit in.” They want to know the pastor and for the pastor to know them. That only happens in a smaller church.
I spent fourteen years in a church of 5,000 people. I was a leader and so I knew many people outside my age group and social circle, but I really only knew a small group of people closely (according to the Switched criteria). So even in large church, your social circle is not any larger, you just have a larger pool from which to draw. The problem is, you will probably be segregated according to some demographic and may not find the person with whom you really should be friends.
Remember how many people were in the upper room on the Day of Pentecost? Yes, 120. Pretty close to Dunbar’s number.
In short, I think Dunbar’s number is innate, we all understand it to some degree and that is why churches flock together around this number. It’s not that small churches want to remain small, it’s just wired into us.