prase comments on Prisoner's Dilemma Tournament Results - Less Wrong

101 Post author: prase 06 September 2011 12:46AM

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Comment author: Unnamed 06 September 2011 02:24:33AM 17 points [-]

It looks like malthrin's bot I may have won only because it defected on the last 2 turns. There were enough defect-on-the-last-turn bots for defecting on the last two to be a smart approach, and of the defect-on-the-last-two bots malthrin's was the closest to tit-for-tat.

In the longer evolutionary run, the winning strategy (O) was the one that defected on the last 3 turns. It stuck around until the rest of the population consisted of only defect-on-the-last-two bots (I and C4), and then it took over.

I'd like to see you re-run this competition, adding in a few variants of tit-for-tat which always defect on the last n turns (for n=2,3,4) to see whether I and O are benefiting from their other rules or just from their end-of-game defections.

Comment author: prase 06 September 2011 09:29:44AM 2 points [-]

Clearly the other features were irelevant when only TfT-but-defect-after-n bots survive. A match between O and C4 or I is always C-C until turn 97, then D-C D-D D-D.

Anyway, what happens when population consists only of TfT-but-defect-after-n bots needs no simulation, a matrix multiplication can do it (also without "random extinctions" due to finite population). Maybe I'll calculate it explicitly if I find some time.