If you thought I was going to talk about the film, YOU’RE WRONG!! Haha. I have no desire to see said film. So we’ll move on.
I am talking about human social groupings. If you watch QI, then you will have heard Stephen Fry mention this topic last week. Apparently, the maximum functional social network is 150. And who has put this fact forward? Well, Fry told you: it was Prof Robin Dunbar. In fact, it is KNOWN as Dunbar’s Number (lucky git! I want my own number!).
So it was my supreme pleasure to hear the topic talked about from the horse’s mouth, so to speak. On Monday, courtesy of UCL’s Institute of Cognitive Neuroscience (ICN), I was able to attend a lecture given by Dunbar, “New dimensions to the social brain: What comparative analysis and neuroimagine have to tell us”.
Usually, the ICN host their lectures in a seminar room in their building’s basement (above). However, they (rightly) predicted that Dunbar’s lecture would be incredibly popular, so had the forethought to hold it in a larger lecture theatre. It turned out to be the lecture theatre in the Clinical Neuroscience Centre (where the BNS meeting was hosted last week).
Dunbar is a wonderful speaker – knowledgeable, clear, concise and witty. Whilst he had a couple of minor difficulties with his slides, he pressed on admirably.
Mostly, when we consider the social brain, we look at the evolution of social groups and correlate these with evolution of the brain. But there is a broader picture: a big jigsaw puzzle if you will, taking in computational psychology, cognitive psychology, social psychology, evolutionary psychology and even neuropsychology.
Why do primates have big brains, particularly large neocortices? On the whole, brain size seems to correlate to a mean group size: a bigger brain means a larger social group. So why the correlation? Dunbar suggests we need the brain power to cope with our complex social systems. It’s not just the fact that there are lots of people in our groups, but we have to cope with managing many individual relationships within the group.
However, this principle seems only to apply to anthropoid primates. We cannot observe the same pattern in other groups of mammals. With other mammals, the biggest brains are found in long-term pair bonded groups, and not big groups at all. An exception? It seems to be horses: horses have a similar social structure to primates, making them basically big primates with hooves.
Dunbar went on to discuss the roles of bonding and parenting within social groups – primates take the principal behind pair-bonds (to provide consistent care for young) and extend it to other group members. This means that a couple can trust a friend or extended relative to care for their young as their own: something animals lower down the phylogenetic scale seem to have trouble with.
So what does this means for humans? Dunbar’s various studies and thorough meta-analyses show humans to have an average social network of about 150 people. This is consistent with records of Neolithic village sizes, modern-day Amish parishes, even military grouping structures. Trust, obligation, familiarity seems to work best in this sort of group size. Dunbar did go into the fractal periodicity behind mammal social grouping (apparently all mammals’ social networks observe a recurring pattern at a scaling ratio of three) but my brain had obviously gone to get some fresh air at that point. If you’re interested in reading more about the mathematics behind social groupings, I’m afraid you might have to do your own research.
Anyway, Dunbar did touch on some of the obvious: social groups are multi-level, and the quality of relationships deteriorate as you go further out in the layers. I’m sure we’ve all observed this ourselves: we have about five super best pals, then a wider circle of close friends, then a lot of people we’d happily go for a drink with, and then a lot of acquaintances that we’re ok making small talk with. Dunbar says that the phenomenon behind massive Facebook friend groups (we all know someone with 500 friends) is fairly easy to explain: these are NOT FRIENDS. They are voyeurs. We know only about 150 people as “persons” – someone with whom we have history.
So how does this bonding work? Well, primates do it fairly simply: a two way process of grooming and… some cognitive component. We’re not sure what. It might involve levels of intentionality – we’re good up to about 5th order. For humans, this sort of processing is only possible with language as a scaffold. Again, it might be worth doing some background reading about mentalising tasks on levels of intentionality.
But back to grooming: it is pretty certainly a linear function of group size. And why does grooming work? It’s all back to endorphin release. We know this because studies using opiates show a decline in social drive. Use opiate-blockers, the opposite happens (increased social drive – gimme endorphins!)
The problem? If humans used primate techniques for bonding, we would spend about 43% of our day grooming each other…
Does language bridge the gap? We spend about 20% of our time in social contact – so how do we cross the bonding gap?
Dunbar suggests laughter, singing/dancing and the rituals of religion as good endorphin releasers. The music and laughter especially (but not just passively listening to music – get up and actively sing, please!)
Laughter and music are human universals – and studies run on the effects of these show massive endorphin release (particularly if done in a group). Higher endorphin levels correlate to higher pain thresholds. So, measure pain threshold, show the subject a funny movie, then measure pain threshold again. It does work surprisingly well.
Exercise is also a good endorphin releaser. But guess what? It works best in a group again. This time, studies were run on rowing teams: training on their own, or training in synchrony. You guess which was more effective. So, with group activities come better bonding and larger social networks. Perhaps a little common sensicle when you look at it in that one-sentence context, but the underlying psychology is pretty neat.
UCL’s ICN runs a weekly public seminar, held in their building in Queen Square. Want more info? Then head on over to their website 🙂