a golfer envisions and attempts to anticipate every shot as if it were going to be a hole-in-one, even though most of them will not be... but in the process, achieves a better result than if s/he anticipated performing an average shot... The compartmentalization that must occur for this to work is that the "far" mind must not be allowed to break the golfer's concentration by pointing out that the envisioned shot is a lie, and that one should therefore not be feeling the associated feelings.

I think maybe the problem is that different neurological processes are being taken as the primary prototype of "compartmentalization" by Anna and yourself.

Performance enhancing direction of one's attention so as not to be distracted in the N minutes prior to a critical performance seems much different to me than the way the same person might calculatingly speculate about their own performance three days in advance while placing a side bet on themselves.

Volitional control over the contents of one's working memory, with a thoughtful eye to the harmonization of your performance, your moment-to-moment-mindstates, and your long-term-mind-structures (like skills and declarative knowledge and such) , seems like something that would help the golfer in both cases. In both cases there is some element of explicit calculating prediction (about the value of the bet or the golfing technique) that could be wrong, but whose rightness is likely to correlate with success in either the bet or the technique.

Part of the trick here seems to be that both the pro- and the anti-compartmentalization advice are abstract enough that both describe and might inspire good or bad behavior, and whether you think the advice is good or bad depends on which subsets of vaguely implied behavior are salient to you (based on skill estimates, typical situations, or whatever).

Rationalists, especially early on, still get hurt... they just shouldn't get hurt twice in the same way if they're "doing it right".

Any mistake should make you double check both the theory and its interpretation. The core claim of advocates of rationality is simply that there is a "there" there, that's worth pursuing... that seven "rational iterations" into a process, you'll be in much better position than if you'd done ten things "at random" (two of which were basically repetitions of an earlier mistake).