On Stuck Priors In Deck Selection


In some ways I feel as though I said everything I had to say about Magic in my first article on this site but I’ve been reminded recently that it might still be worthwhile to write some things I think are obvious. In that spirit, let me elaborate on the subject of stuck priors.


One-tricks are a relatively common phenomenon across the landscape of the game and there are fairly good reasons for this. Tuning the slots of a deck you are familiar with is always easier than exploring a broader possibility space of all possible decks, you don’t have to experience the painful struggles of incompetnce as you learn a new strategy, and perhaps most importantly playing the same deck becomes self-reinforcing at a certain point. Not only is your perception of the deck in question buffered by vast reps making it seem more appealing than it really is but also it will be often better for your short run winrate to play the familiar deck than the technically stronger unfamiliar one. I’ve run into this a number of times myself but luckily got a wakeup call quite early in my tenure playing the game when I saw Claudioh refer to me in a Twitch chat as “mono Genesis Ultimatum” and since then as evidenced by my Goldfish history I have largely been successfully in avoiding lock in. Scott talks about this in his Trapped Priors As A Basic Problem Of Rationality, saying “priors can update normally until they reach a certain strength, and after that they’re trapped and can’t update anymore. Probably this isn’t true. Probably they just become trapped relative to the amount of evidence an ordinary person is likely to experience“.

Interlude: Pro Tour Phyrexia

If you were tuned in at any point during coverage of the most recent Pro Tour you most likely heard casters push a narrative of decks largely being equal with personal experience and comfort being a breakpoint. This should make you suspicious. Their incentives are not aligned with basic truth-seeking, let alone your best interests if you are the type of person who is reading my post. Sure, in most cases it is not viable to invest the amount of effort you would need to confidently find the best deck but you should still be trying to do so both given the top-heavy nature of event payouts and to increase long-run range. And although I may biased I do think that the Sewer Rats team that did a pretty broad sweep showed up with a number of members on an innovative deck that was the best in the room.


End Interlude

So where does that leave us? Particularly dedicated teammates might be able to get you out of this hole but that isn’t at all guaranteed and most people don’t have access to such help. The most promising intervention in my eyes (although I cannot speak to the possible effectiveness of mind-altering substances) is intentionally cultivating an identity as someone who pushes back against local maxima. Whenever you notice yourself registering the same deck over and over again, stop and really ask yourself if it the best option ideally only making that decision after playing some fresh games with other contenders. Whenever you are trying to make a close call between two decks, default to the one you are less familiar with. Small but concrete trigger action plans like this are the way to funnel willpower from a stronger version of yourself to arbitrary points in the future and make sure you are able to execute when it matters.

None of this is specific to Magic either. The same principles apply everywhere in life that you want to make more effective decisions. Agency is one of the most important traits and being the sort of person who just Does Things™ is immensely valuable.