If the tournament were run a second time, my expectation would be that such programs would abound (since writing "if they showed signs of life randomly do something but usually defect, else cooperate" is pretty easy), there'd still be a bunch of simple guys running around, there'd be a small number of people trying to play higher-level exploit games that would have better code than last time, and you'd likely see a level-2 bot (one that beats the obvious level-1 bot that wins the first tournament) come out ahead.

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)

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)