Dunbar's killer fact on friendship
By Mark Vernon on Sunday, January 31 2010, 08:00 - Philosophers on friendship - Permalink
Heard of Dunbar's number? You're likely to soon, as the evolutionary anthropologist, Robin Dunbar, has a new book out, How Many Friends Does One Person Need? It's 150, and it's the typical size social groups should be, based upon the size of the human neocortex. Moreover, it apparently turns out that the number 150 is about the size of certain social groupings, from medieval villages to Roman cohorts. Maybe - though I note my dictionary says cohorts were between 300-600. Also, Dunbar's number has been defined as a limit on the number of 'stable relationships' any one person can maintain, when here in the UK, at least, I maintain stable relationships with about 60 million others. It's called democracy. One does wonder whether the number means anything at all.
But that aside, it's worth asking this: why is the number so compelling, particularly in relation to friendship?
After all, what would be surprising is if Dunbar's number was, say, 15 or 1500, and yet still groups were around 150. That would require an explanation. But that a bit of the brain seems about the right size for the life we actually lead is like observing that hands are about the right size for writing.
The thing that worries me is the instrumental approach to friendship the number nurtures. From being an evolutionary aside, almost a tautology, it has become a prescription - as the title of the book reveals: you need 150 friends.
Quantity is a perfectly sensible question to ask when buying apples at the supermarket. But we have a different relationship with people. They are I-Thou relationships, as Buber put it, not I-It, as the quantitative assessment makes them. Turn an I-Thou into an I-It, and you kill friendship stone dead. It's love by cost-benefit analysis; agony aunt advice from accountants. My friends are the service providers in my optimized life. Better go out and get them.
I've not actually read the new book as yet, so maybe I should lighten up. Perhaps it comes with a health warning. The trouble is that ostensibly at least, it's treating human beings as machines, the brain as a computer - and that is a pervasive hermeneutic in contemporary culture. As Iain McGilchrist notes, neuroscience has got stuck on the question of what the brain does - a dysfunctional, left-hemisphere-dominant mindset. The worry is that everyone else gets stuck in that mindset too.
For staying with the issue of friendship, it's clearly the case that everyone likes to be useful to their friends. But feeling that you are being used in a friendship is something very different - the first sign of its terminal decline. Perhaps the number should be renamed Dunbar's killing friendship fact.
Comments
Would you not agree that in social groups of no greater than 150, everyone could know everyone else and thus any recidivist tendency on your part would be reduced through the shame factor derived from the knowedge that shoudl your crime be discovered you would have to face the victim of your crime almost on a daily basis? Crime would become personal, rather than impersonal, as it invariably is in large towns today.
General point accepted - except why 150? My school had maybe 500 pupils in it, maybe more, and we all knew who the bastards were.
;o)
Dunbar's number isn't about the number of people you can recognise, or have some kind of relationship with, or even maintain a friendship with but the number of people that you can practically and personally relate to in an institutional and co-operative context. It has a lot of anthropological observation to back it up, but it's not a precise number - it's rather in the range of 150-200.
You may well have known the names and faces of 500 pupils, but the school as an institution doesn't co-ordinate activities like a company or tribe. Students are dealt with in groups of up to 30 at a time, except in assemblies or other situations in which a group activity is monolithic.
The claim behind Dunbar's number is that there is a cognitive limit to our ability to work in coordinated groups above a particular size; above this size, people can remain "allied" but pragmatically the larger group must devolve into smaller groups. Your school, I'm betting, did not consist of one class of 500 students, but more like 20 classes of 25 students (say). This is well below Dunbar's number.
I came across this via Gladwell's Tipping Point. In this, Gladwell also observes people who maintain massive social networks - much larger than 150-200. But such people do not interact with the members of their social group in the same way that co-workers in a company (or members of a tribe) co-operate, and it is this function of working together which seems to be at task.
All the best!
As Chris says it's not actually 150. 150 is the casual expression of a less tractable quantification. As reported by Robin Dunbar the actual number for humans lies between 100 and 230 with 95% confidence whilst for gorillas it is 13.
It is a statistically derived number and with such a large confidence interval it's not very precise - but still useful. The size of organisational units within the human military and of villages prior to the industrial revolution tend to support it.
I am not personally privy to gorillas' ideal organisational units but a study of Che Guevara's modus vivendi might reward the effort should the question be significant.
For me Dunbar's Number brings clarity to the problems experienced in our big cities and why I shun such horrid places as London. I lack the skills in cognitive dissonance which would allow me to perceive comfortable units of 150 within a horde 20M strong.