Right. I noticed this acutely in an abstract algebra course. We learned several different proof methods, then the exam was just "prove these theorems with the tools you have". I'd never been challenged with math like that before. I mean, I bombed it lol, but nobody was going to pass if they didn't remember, say, how to do a proof by induction or what it means. At some point, you need to be able to recall this information. Maybe the psychologists categorize these things differently, but I'd argue it's clear that some form of memorization is necessary for the task.