Slashdot reports:
“Tit for Tat, the reigning champion of the Iterated Prisoner's Dilemma Competition, has been defeated by a group of cooperating programs from the University of Southampton. The Prisoner's Dilemma is a game with two players and two possible moves: cooperate or defect. If the two players cooperate, they both have small wins. If one player cooperates and the other defects, the cooperator has a big loss and the defector has a big win. If both players defect, they both have small losses. Tit for Tat cooperates in the first round and imitates its opponent's previous move for the rest of the game. Tit for Tat is similar to the Mutual Assured Destruction strategy used by the two nuclear superpowers during the Cold War. Southampton's programs executed a known series of 5 to 10 moves which allowed them to recognize each other. After recognition, the two Southampton programs became 'master and slave': one program would keep defecting and the other would keep cooperating. If a Southampton program determined that another program was non-Southampton, it would defect.”
Haven't read the paper yet, but this sounds like a significant result, as the empircal superiority of 'tit for tat' is received wisdom in most accounts of applied game theory I've ever read. 'Ascription is an Anathema to any Enthusiasm' calls it delightful and suggests that,
This is the classic model of all game theory! And even in this tiny little dishpan model collaborative groups form and once they form they out compete the players that fail to collaborate. As Dave Weinberger once pointed out, we are a species that will form communities even if it means tapping out the alphabet on the wall of our cell.
I wonder if real-life applications may be limited by the difficulty of the earlier game to determine who gets which role…
