The Rule of 150

I came across a fasincating concept the other day - from Malcolm Gladwell's The Tipping Point.

The number '"150" siginifies the maximum number of people we can have a genuinely meaningful relationship with. This is a number calculated through an equation involving the size of part of the brain responsible for social behavior. So in layman's terms: the 151st person on your phone book is probably someone whose name you'd forget at a chance meeting.

Here are a couple of interesting examples of the number at play.

• A study found that the average number of certain hunter-gatherer type tribes in Greenland and Australia turned out to be 148.8.
• There is a rule of thumb within the army, as well, that the most efficient and effective units tend to be under 200 soldiers.
• Also, a religious community known as the Hutterites have over 100s of years stuck to the code that once they have grown past 150 individuals, it would once again become time to split the community and separate.

Through trial and error, all these communities have learned the Rule of 150.

How cool is that?!

(credit The Tipping Point by Malcolm Gladwell)