The Dunbar Number 150

The way in which our social world is constructed is part and parcel of our biological inheritance. Together with apes and monkeys, we’re members of the primate family – and within the primates there is a general relationship between the size of the brain and the size of the social group. We fit in a pattern. There are social circles beyond it and layers within – but there is a natural grouping of 150.

This is the number of people you can have a relationship with involving trust and obligation – there’s some personal history, not just names and faces.

Robin Dunbar  The Guardian March 10, 2010

Sebastian Junger in his latest book, War, summarizes the significance of the Dunbar Number:

  • Dunbar compared the brains of primates and contemporary humans and and used that ratio to come up with 150
  • The neocortex is the part of the brain most relevant to increasing and limiting the number of personal relationships
  • Hunter-gatherers lived in informal communities of between 90 to 221 people – Neolithic villages are estimated to be around 150
  • Larger numbers are difficult to control with peer pressure alone
  • Communities of 150 began to find common benefits in social and defensive relationships that began to form tribes and confederacies
  • The idea of “us” and “them” was more pronounced with different languages and cultures evolving

Violence, War, Cruelty, Suffering: The Mark of Mankind

Junger goes on to remind us that our evolutionary past suggests up to 15% of all deaths were in violent confrontations with other groups and tribes. To put that in perspective only 2% died from wars and violence in the twentieth century, but of course the overall numbers in the last century is a magnitude beyond any real comprehension, and certainly dwarfs the 15% throughout prehistory.

Mankind has a great capacity for killing each other and there is absolutely no evidence that it will not continue unabated. Most importantly, we have the means to finally destroy not only ourselves but also the means for the planet to regenerate itself.  In other words we have become so brilliant, we can, if we so choose, make this planet a veritable desert with all life forms ceasing to exist.

Now that’s a legacy we can all be proud of!

Overpopulation and The Dunbar Number

What should be most worrisome for all of us if this Dunbar Number can be believed, and there is no real reason not to at least give it some credibility, is that we are evolutionarily wired to resist large numbers of people around us.  Suspicion, paranoia and fear seem to be a natural phenomenon and reaction when certain numbers are reached. Consequently, we do feel out of control and unable to maintain a spirit of community and companionship when individual relationships, business connections and social networks begin to approach 150 people and larger.

That could be a reason for our general uneasiness with the size of governments at the federal, state, cities and local levels. How about corporations and large businesses, hospitals, the military and other organizations that have become so immense and cumbersome that we simply don’t trust them to establish a meaningful relationship with us? 

Instead of us controlling them, they manipulate and control us.

And of course, if we are feeling uncomfortable living and working with 300 million people in this country, what about a world that approaches seven billion! If 150 is the estimated maximum, the neocortex must be in a constant state of agitation and anxiety just trying to comprehend much less assimilate the sheer volume of those numbers.

Technology can deceive us into believing we are in communication with the entire country. We watch television, operate our computers, communicate on our cell phones, read our newspapers and magazines and believe we are in touch with the rest of the country and even the world. 

But for all of that, we actually know very little or nothing about the vast majority of people whom we have any contact with through any of the media or communication networks. And deep down we all know viscerally that our lives are an illusion of connection rather than of any substance.

In the end we have very little control of our lives where some live in privilege and good fortune while others suffer lives of poverty and want. It is no accident then that jails, prisons, mental institutions are full of those unable to live in a culture cluttered by too many people competing for declining resources, which are being consumed at an ever increasing rate. 

The Dunbar Number may not totally explain the ramifications of the overpopulation quandry we find ourselves. Nevertheless, it certainly gives us a fascinating insight and clue into the human psychic and evolutionary biology. That puzzle and consequent feelings of alienation and confusion may help explain why more is less and many more will most likely lead us to our ultimate downfall.

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