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This review is from: The Evolution of Co-Operation (Penguin Press Science) (Paperback)
This book features the results of a famous computer tournament that Axelrod ran. Various strategies for The Prisoners' Dilemma game were entered and played in a round-robin format. Players in this game have two strategies: "Defect" and "Cooperate". The players' payoffs are maximised as a group if both players Cooperate. However, for the players as individuals, Defect will give them a higher short-run payoff no matter what their opponent chooses.
When this game is indefinitely repeated, the strategic conundrum is to find a way to cooperate with willing collaborators, while preventing ruthless defectors from exploiting you. Axelrod found that the best performing strategy in his tournament achieved both of these aims: called "Tit for Tat"; the strategy would cooperate on the first round and copy its opponent's last move on all following rounds. This means it would cooperate if its opponent did, but respond to a fefection in like manner.
This is highly interesting, and Axelrod uses an example of how some opposing battalions in the trenches during the First World War used similar strategies (the so-called policy of "live and let live"). The author finds this all so stimulating that he posits Tit for Tat as the canonical solution to how cooperative behaviour can evolve in society and biology.
The trouble is that this is quite a far-reaching claim, and some game theorists became suitably irked. In particular, Ken Binmore explains in Playing for Real how a classic result in game theory -- the folk theorem -- shows how many different forms of self-interest cooperation can arise in indefinitely repeated games. This means that the author's claims for Tit for Tat are not quite accurate: many different forms of collaboration amongst selfish agents can arise. Indeed, Tit for Tat has not always prevailed when similar tournaments have been repeated.
However, this book does do a good job of explaining how cooperation can evolve to a wide audience, and I would definitely recommend it.