A recent BBC documentary
duppeddubbed the 20th century as the century of the self. In general, the modern (western) society has been seen as a dominantly individualist, selfish social structure. People don’t care about each other, the poor are abandoded, if somebody is lying on the street they’ll just get passed by etc.
The evolutionary game theorists have shown (mathematically) that in people may well be co-operative, because it’s the best strategy (in the evolutionarily stable sense) for the individual. Imagine that human interactions can be described by the following two-party (A and B) game:
- if A co-operates and B co-operates, both win 100
- if A defects and B defects, both get 10
- if A co-operates and B defects, A loses 10 and B gets 120
(note that it’s definitely not a zero-sum game, think e.g. agriculture or the hunting of a Mammoth, for example in the Mammoth case co-operating means hunting together).
Now the maths show that if this game is repeated, the stable strategy for a population (this is slightly wrong, bear with me) is what we can call ‘tit-for-tat-start-co-operative’. That strategy means that
- when you meet a stranger, in the first round you co-operate
- after the first round, you do whatever the other person did last (so if they defect, you defect)
This can now be seen as the basis for many of our ‘fast and frugal’ cognitive strategies: liking, social ties, families and tribes, anger, revenge, memory, remorse, guilt, thankfulness etc. Since we can communicate, there are even things like reputation, so you don’t actually need to have played the same person before, they will repeat whatever you played last against anyone.
The thing is, empirical game theoretical studies have shown that people are not quite that simple. They will co-operate if they think that the other player will remember that and that they will play again. Or put it the other way round: when people are really sure they won’t get caught, they always defect. Even the nice people.
So when you have, say a tribe of 30, whatever you do will be known to the other players, and games are always repeated. So you co-operate.
The thing is, when you have a city of 10 million, passing somebody in need by won’t get noticed by anyone you are going to play with. So you defect.
So in a way, this selfishness is a product of modern times. But the underlying mechanism has always been the same. Our chances of getting caught are just getting smaller and smaller.
And now the thing I lied about: actually, the tit-for-that isn’t quite evolutionarily stable. A small proportion of the population can play ‘always-defect’. As long as the proportion is small enough, they’ll mostly meet new other players who will co-operate on the first round, and they’ll get more. If the proportion gets too large, they’ll start losing since they’ll be meeting each other as well and getting a very small payoff. This is why we have sociopaths.