The Magic Number of 150

"...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 the idea from contemporary evolutionary psychology. They've been following the 150 rule for centuries. But their rationale fits perfectly with Dunbar's theories.

At 150, the Hutterites believe, something happens - something indefinable but very real - that somehow changes the nature of the 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."

(Then he goes on to give the example of Gore Associates, a privately held, multimillion-dollar-high-tech firm based in Newark, Delaware, who have been wildly successful, by using the Rule of 150 - all their plants only have 150 people - when the number exceeds that, they just create a new division, not far from the first, but yet again only holding 150 employees. There is no visible hierarchy in the group.)

"The kind of bond that Dunbar describes in small groups is essentially a kind of peer pressure: it's knowing people well enough that what they think of you matters. The company is the basic unit of military organization because, in a group under 150, "orders can be implemented and unruly behaviour controlled on the basis of personal loyalties and direct man-to-man contacts."

"Once that line, the Tipping Point, is crossed, they begin to behave very differently."

Page 180. 'The Power of Context (Part Two) - the Magic Number of One Hundred and Fifty'

From the bestseller - 'The Tipping Point - How Little Things Can Make A Big Difference' by Malcom Gladwell