Game Theory

The rules of medieval warfare that I was talking about on Monday are an example of game theory. I used a similar system when playing a board game called Britannica at university. The game was for four players who each took control of some of the tribes who invaded Britain during the Early Middle Ages. It began with the Romans and ended with the Normans. My long term strategy was to make sure that if anyone backstabbed me, I would do everything I could to destroy their chances in that game. I’d even throw away my own chance of winning to get revenge. Now in the short term, this was a silly idea because it meant I was more likely to lose the game. But my betrayer had no chance either so in the long term (we played each week) people stopped backstabbing me even if I left my troops in a vulnerable position.

Much later, I found out that my strategy had been discovered by game theorists and is known as tit-for-tat. Ethologists (who study animal behaviour) have detected a very similar strategy being used by non-humans and have noted that it is so successful that it confers an evolutionary advantage on organisms that use it.

In the idealised surroundings of playing Britannica tit-for-tat works well but in the real world it suffers from a serious problem. When we played our game, each week was a blank slate and I never carried my vendettas over (largely because I couldn’t remember who backstabbed me the week before). In reality, tit-for-tat can often descend into cycles of violence where retaliation leads to another counterattack which can carry on through generations. The obvious contemporary example is the conflict between Israel and the Palestinians where each Hamas suicide attack inevitably leads to a violent response by the IDF, which in turn leads to more attacks by the militants. Because there is no overarching authority, there is no way to end the cycle of violence and vendetta until one side or the other is defeated.

Of course, in nature, there is no overarching authority and so tit-for-tat is the best that evolution can come up with. We humans can make a better job of things because we use two additional tools. The first is empathy, which causes us to be nice to other people because we feel their pain. The second is the government has a monopoly on retribution that prevents us from taking matters into our own hands. Of course, this means that teaching children to respect authority is every bit as important as encouraging them to emphasise. We reap the benefits of living in a society much less violent than our ancestors. It is worth asking, as I will be in the next few weeks, how we got here.

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