I'm in the "fish absolutely learn", camp.....
No, say it ain't so! You mean that they can tell the difference between an AM500 and an AM600 pellet?
I caught a bunch of BG in a local lake a number of years ago on a white twister tail. The BG in that lake just hammered it every time I used it. I put a number of those fish in my pond after I had a winterkill right after I purchased this place. Guess what? Yep. I couldn't catch them in this pond on that same lure.