...But the evolutionary mechanism need not be a question of life or death [i.e. the gene].
With intelligent players, a successful strategy can appear more often in the future because other players convert to it. The conversion can be based on more or less blind imitation of the successful players, or it can be based on a more or less informed process of learning.
The mechanics of the evolution of cooperation can be Classical Darwinian survival of the fittest and mutation, but they can also involve more deliberate processes such as imitation [mime-] of successful patterns of behavior and intelligently designed new strategic ideas [meme-]. (p175)
The Evolution of Cooperation
Robert Axelrod, 1984
revised edition w foreword by R. Dawkins, 2006
for further talk and controversial ideas against Axelrod's theory, see this Edge conversation:
ON "ITERATED PRISONER’S DILEMMA CONTAINS STRATEGIES THAT DOMINATE ANY EVOLUTIONARY OPPONENT"
William H. Press, Freeman Dyson [6.18.12]