for reference, here's what I was "planning"-I was all too aware i didn't have time to learn a new language to actually implement it in. a pity i didn't think to post this before the tournament results, even if it's just pseudocode...

run(me,opponent){ //start point notethetime() if(me=opponent){return C} defectbot[]=a list of primitive defectbots with a junk string value added run5times and record results:(run(opponnent, (opponent, defectbot[i]) { if (opponent cooperated sometimes){ if(isooponentclearlymimicbot(ooponent)){cooperate()}else{defect(... (read more)

I find cooperation with cooperation-bot utterly insane in context; I would have predicted less than three, but a good chance of at least one. In the real world problem, or a tournament with a lot of rounds, it's potentially worth saying that since C-bots will die off quickly (although, if enough people cooperate with them, maybe they won't) they're effectively unlikely enough that you can safely use your response to them as signaling for other programs, but if that's true, then your opponent should presumably know that and throw non-trivial cases at you instead.

Prisoner's dilemma tournament results

by AlexMennen 1 min read9th Jul 2013124 comments


The prisoner's dilemma tournament is over. There were a total of 21 entries. The winner is Margaret Sy, with a total of 39 points. 2nd and 3rd place go to rpglover64 and THE BLACK KNIGHT, with scores of 38 and 36 points respectively. There were some fairly intricate strategies in the tournament, but all three of these top scorers submitted programs that completely ignored the source code of the other player and acted randomly, with the winner having a bias towards defecting.

You can download a chart describing the outcomes here, and the source codes for the entries can be downloaded here.

I represented each submission with a single letter while running the tournament. Here is a directory of the entries, along with their scores: (some people gave me a term to refer to the player by, while others gave me a term to refer to the program. I went with whatever they gave me, and if they gave me both, I put the player first and then the program)

A: rpglover64 (38)
B: Watson Ladd (27)
D: skepsci (24)
E: Devin Bayer (30)
F: Billy, Mimic-- (27)
G: itaibn (34)
H: CooperateBot (24)
I: Sean Nolan (28)
J: oaz (26)
K: selbram (34)
L: Alexei (25)
M: LEmma (25)
N: BloodyShrimp (34)
O: caa (32)
P: nshepperd (25)
Q: Margaret Sy (39)
R: So8res, NateBot (33)
S: Quinn (33)
T: HonoreDB (23)
U: SlappedTogetherAtTheLastMinuteBot (20)