"One Man's Modus Ponens Is Another Man's Modus Tollens"

The examples in the buckets error [LW · GW] post have "modus delens" as the correct response. To take the diet example from the post, A = "diet worth being on", B = "zero studies suggesting health risks". Adam has $A⟹B$ stored in his brain, and Betty presents $\neg B$, so Adam's brain computes $\neg A$. The "protecting epistemology" move is to instead adamantly believe A ("I need to stay motivated!") which ends up rejecting what Betty said. But the desired response is to instead deny B but also accept A, and hence to deny the implication $A⟹B$.

So in these buckets error examples, modus ponens corresponds to the "automatic" reasoning, modus tollens corresponds to the "flinching away from the truth" move, and modus delens corresponds to the "rational" move that avoids the buckets error.

I explained this more in a comment [LW(p) · GW(p)] on the post.

I can't comment as to the relative frequency of this response and how often it's correct (this sort of question seems difficult to answer).