How we change what others think, feel, believe and do
The ChangingMinds Blog!
Communities and the magic 150
I went to school back in the days when schools were small. My junior school had about 100 pupils and my secondary school about 250. I knew everyone in the first school and many in the secondary school -- I recognised everyone and knew most by reputation or family. The school seemed big after my first school but I got used to it. I didn't realise it at the time, but I was subject to the Law of 150.
Man is historically a tribal animal. Evolution has taught that living in cohesive groups works better than trying to survive alone. Cities are relatively recent inventions -- village-sized communities are the living groups that we've been used, and it's interesting how, even today, neighbourhoods are often a more important component of our identity.
The magic number for 'large' groups turns out to be 150 people. Larger than this and we find it increasingly difficult to know everyone. Consequently, there is less interpersonal loyalty and less overall cohesiveness. And it all goes back to the size of the villages in which we lived for so long. When people did not travel much, they would be lucky even to meet more than a few hundred in their entire lifetime.
The implications for modern business is to avoid large units, fragmenting primary groups into units around this size. An example from my history is in Hewlett Packard, where divisions would spin off.larger developments into new divisions. It is no surprise that, from the days of the monolithic behemoth, HP was a nimble player who rose to the top of the computer industry..
They all look the same to us, but I guess to a seagull, that lass over there is strangely attractive...
We do this with out-groups and stereotypes. Long/short-haired kids these days (let along other ethnic groups) do look rather similar. The thing to remember is that we also look similar to them.
I believe I'm right in saying that 150 is also the number at which most
growing churches get stuck, unless they create other methods (typically small
groups) to preserve feelings of community. Ironically, the larger the church the
more lonely a visitor feels. Small groups provide the route into deeper
And the big