I suffer as well from the “forgetting” phenomenon.
Just reading all these replies has been very helpful! Thank you all!
Here’s my little drop in the ocean:
I have found learning from the dots and to targets to be very hard and not helping much. What I am now doing is just scales, arpegios and cut/tap/roll/cran exercises. This is helping enormously. So now, I am finding that once I hear a tune enough I can play it. In short, I am working on the vehicle, so when I know the road, I can drive it and the fingers will get the tune under them like the gravel under my wheels.
I had a similar thing on guitar. There is an exercise that was the bestest ever for guitar and I’m finding it really excellent on whistle as well. It goes like this:
Start on each note and do the following pattern:
1 2 3 4 5 4 3 2 1 2 3 4 5 4 3 2 1 5 4 5 3 5 2 5 1 5 2 5 3 5 4 5
It’s easy enough up to where you have to cross into the second octave. And this is where you need to do it most. The rules are = play at an even tempo, if you break tempo start again, start on D then E, F# G, A, B, C# all the same tempo, when you fumble and have to start again, slow it down a touch - a metronome is handy, when you do the lot without breaking tempo THEN turn the tempo up a notch. This exersize was invented by Andre Segovia - It works.
Ultimately, you think in melody and the muscles already know where to find the notes. This connects your creative heart to what you’re playing. With technique, there is a crossing point - you will pick up your instrument one day, and it will seem somehow smaller - Frank Zappa said “Little Guitars”.
The other thing, since we are talking about how the brain works is this - practice new stuff in a noisy environment, then refine it in a quieter one. Never practice in absolute silence - noise is essential for removing “local minima” where you think you know but you don’t. This also applies to listening to new tunes - have the TV or another piece of music playing as you listen to your target. Idealy you would gradually reduce the environmental noise with each listenning. Silence is what an audience gives you when you perform - that audience might be you or a microphone when you record yourself.
Be careful about “Associative” technique - if you key a string of tunes to an association, you will lose the lot if you lose the association. You could die by chunks. We are a continuum - keep your options organic. Policy works better than rule, this is because policy is based on natural justice and can be re-constructed - policy morphs and keeps its history, while bald rules exist as dogmatic symbols in void - they are subject to extinction - which is OK if you only need them once.