I don’t think the “spoil the setup” experiment distinguishes TDT from the belief in fairness. Just because the second person’s decision comes after the first doesn’t mean it has no effect on the first. It’s very much like Newcomb’s problem in that regard, and one of the main points of TDT was to account for that effect. Depending on the details of the rewards and how strongly you think the other player’s decisions correlate with your own, it may make sense to precommit to cooperation even if you’re told the other person’s choice. And if it makes sense to precommit to cooperation, that’s what TDT will do (unless I’m missing something).
The superrationality explanation still makes sense. If the other player’s choice is known, then symmetry is broken, so the superrational agent should defect.
Other than that, I’m not really sure what you mean by “explanation”. The “folk version of superrationality” sounds plausible, but the underlying causes of the experimental results still feel pretty mysterious. Demystifying them is well beyond my capability, but it’s certainly an interesting question.
I don’t think the “spoil the setup” experiment distinguishes TDT from the belief in fairness. Just because the second person’s decision comes after the first doesn’t mean it has no effect on the first. It’s very much like Newcomb’s problem in that regard, and one of the main points of TDT was to account for that effect. Depending on the details of the rewards and how strongly you think the other player’s decisions correlate with your own, it may make sense to precommit to cooperation even if you’re told the other person’s choice. And if it makes sense to precommit to cooperation, that’s what TDT will do (unless I’m missing something).
Do you have an alternate explanation for why so many fewer people cooperated in the “spoil the setup” experiment than in ordinary experiments?
The superrationality explanation still makes sense. If the other player’s choice is known, then symmetry is broken, so the superrational agent should defect.
Other than that, I’m not really sure what you mean by “explanation”. The “folk version of superrationality” sounds plausible, but the underlying causes of the experimental results still feel pretty mysterious. Demystifying them is well beyond my capability, but it’s certainly an interesting question.