Actually, I think the proper case is “Two players play a one-player game they can either win or lose. One person follows, so far as able, the tenets of TDT. The other decides by flipping a coin. The coin-flipper outperforms the TDTer.”
I mention this because lots of decision theories struggle against a coin flipping opponent: tit-for-tat is a strong IPD strategy that does poorly against a coin-flipper.
Is there any decision strategy that can do well (let’s define “well” as “better than always-defect”) against a coin-flipper in IPD? Any decision strategy more complex than always-defect requires the assumption that your opponent’s decisions can be at least predicted, if not influenced.
No, of course not. Against any opponent whose output has nothing to do with your previous plays (or expected plays, if they get a peak at your logic), one should clearly always defect.
Not if their probability of cooperation is so high that the expected value of cooperation remains higher than that of defecting. Or if their plays can be predicted, which satisfies your criterion (nothing to do with my previous plays) but not mine.
If someone defects every third time with no deviation, then I should defect whenever they defect. If they defect randomly one time in sixteen, I should always cooperate. (of course, always-cooperate is not more complex than always-defect.)
...I swear, this made sense when I did the numbers earlier today.
Actually, I think the proper case is “Two players play a one-player game they can either win or lose. One person follows, so far as able, the tenets of TDT. The other decides by flipping a coin. The coin-flipper outperforms the TDTer.”
I mention this because lots of decision theories struggle against a coin flipping opponent: tit-for-tat is a strong IPD strategy that does poorly against a coin-flipper.
Is there any decision strategy that can do well (let’s define “well” as “better than always-defect”) against a coin-flipper in IPD? Any decision strategy more complex than always-defect requires the assumption that your opponent’s decisions can be at least predicted, if not influenced.
No, of course not. Against any opponent whose output has nothing to do with your previous plays (or expected plays, if they get a peak at your logic), one should clearly always defect.
Not if their probability of cooperation is so high that the expected value of cooperation remains higher than that of defecting. Or if their plays can be predicted, which satisfies your criterion (nothing to do with my previous plays) but not mine.
If someone defects every third time with no deviation, then I should defect whenever they defect. If they defect randomly one time in sixteen, I should always cooperate. (of course, always-cooperate is not more complex than always-defect.)
...I swear, this made sense when I did the numbers earlier today.