The limitations of our brains

Apparently there is a linear correlation between ape brain size and troop size. In other words, the larger an ape's brain, the larger the size of the troop it naturally forms.*

Interesting.

Extrapolating from the ape data, that means humans would naturally form communities of no more than 200, which seems to actually be the case with self-contained non-hierarchical societies.


Apparently our brains can really only handle tracking that many individual personalities. In small groups, it's possible to know who to trust and who you can't because their reputation develops quickly and everyone knows it. If you've ever lived in a village or small town, you can see that happening quite naturally.

So how do we live in such large societies? Social roles. We've invented institutional roles e.g. priest, policeman, king, teacher, criminal, in order to create a kind of short-hand that allows us to live in such large groups. Instead of having to know thousands of individuals, we just need to know several hundred social functions. Of course we've had to develop a large set of rules and conventions to govern interactions between different groups, but by labelling people according to their position in society, we are able to interact with that many more people.

And of course we can switch from one category to another. And we occupy different social roles in different contexts. But as I think about it, I probably know the personalities of a couple hundred people (at most) but more than that would be overwhelming. Allocating some of the people I interact with to the shorthand of social roles certainly makes it easier to deal with the large groups we live in.

It also makes it easy to forget how many people we really do live with. I know as I go through life, I really only pay attention to the people who I come in contact with. I forget that there are hundreds, or thousands, or even millions, standing in the wings, where I can't see them. They're going through their lives the same way I am - interacting with only a tiny portion of the number of people in a given space.

It's easy to forget that everyone of those apartments in that block is home to at least one person. As I drive by the apartment block, all I see is the building, one of many that I pass on my journey. Trying to imagine all those people in that building, multiplied by all the buildings I might drive past on one short trip to the store would be mindboggling. The numbers alone get large very quickly, let alone trying to imagine personalities to go with all those bodies. No wonder we only attend to a small portion of the population that we interact with. Otherwise we'd spend all our time worrying about social interactions.

Our brains are limited in this capacity to deal with information. Even with external brains like address books, PDAs, or even business card collections, we are often reduced to this kind of short hand to organize all the social interactions we have in a given day. I guess it's not a bad thing, just an interesting human limitation.

*Hans Moravec's Robot: Mere Machine to Transcendent Mind p4