The Evolution of Cooperation - Robert Axelrod

This book is about strategy when playing iterated prisoner's dilemma (and associated real-world equivalents). It was first printed in the early 80s, constructed from a few papers off the back of a computerised iterated prisoner's dilemma tournament. It feels a bit like it, being slightly short and repetitive, but that's mostly because it's repeating a few, interesting core ideas.

I think the most interesting bit is what strategies work best, and why. So, I'll summarise that bit of the book here. The 'tit for tat' strategy works really well - in this strategy you start off cooperating, and then every go you do to your opponent what they did to you in the last round. So far, so dull, but they then analyse the reasons why:

  • It starts trying to be nice.
  • It responds quickly to slights.
  • It's forgiving (if your opponent becomes nice again, so do you).
  • It's easy for the opponent to understand.

So, apparently being nice, quick to anger, quick to forget and straightforward is a pretty good way to live your life, game-theoretically.

Posted 2008-08-09.