The term "Prisoner's Dilemma" comes from the original anecdote used to illustrate this game of strategy. Two prisoners, held incommunicado, are charged with the same crime. They can be convicted only if either confesses. If both prisoners confess, their payoff is minus one. If neither confesses, it is plus one. If only one confesses, he is set free for having turned state's evidence and is given a reward of plus two to boot. The prisoner who holds...