I recently tried out an app called Perfect Ear. You can test your recognition of intervals either from hearing audio or reading dots. It also has exercises for scales and chords.
The experience reinforced what George has said in previous threads about reading, hearing, memory, and physical control of the instrument being distinct processes. I play three instruments and have learned some tunes by ear, some from sheet music, and some from a combination of reading lead sheets and listening to recordings. For me, touch, hearing, and visual cues are complementary parts of learning music, but its interesting to isolate those elements to see what needs the most work.
If you are puzzling over muscle memory, playing by ear, or sight reading here are some other experiments to try:
-When you look at a familiar piece of sheet music, can you hear the tune in your head? Can you visualize the sequence of key presses on your accordion? If you press the keys without moving the bellows, is it harder to play than when you have audio feedback? What if you block your minds ear by saying the rhythm with a monotone rat-tat-tat as you press the keys?
-Can you sing the whole piece? Can you do it without sheet music or charts?
-Can you take a piece of music that you learned on another instrument and play it on accordion?
-Can you transpose a simple, familiar melody to a more difficult key?
-Can you read something in an unfamiliar clef? I tried playing along with my sons beginner viola material. I cant recognize the notes on Alto Clef, but I could sometimes identify the intervals well enough to follow along.
-When you hear a three-chord folk song, can you recognize I, IV, and V chords well enough to follow along using Stradella Bass? Does it matter what key the song is in?
Hmm, theres no good answer to that because what I wrote is incoherent. Ill delete my original post and try again.
Muscle memory, playing by ear, and sight reading have been discussed in previous threads. I play both by ear and from sheet music so find it interesting how it all fits together.
I had assumed that when I play from the dots, I read a note and interpret that as a key to press on the accordion, with the goal of getting comfortable with and memorizing the physical movements involved. Thats what I think of as muscle memory and its definitely part of it, but its not the whole story.
Its also the case that when you play music, youre hearing it, and hearing it reinforces it in your memory. Some tunes I originally learned from sheet music are now stuck in my head well enough to hum, sing, or play (haltingly) on a different instrument or in a different key, as if I was learning it by ear.
Then theres a third skill Id never thought about--recognizing intervals and patterns in the dots. My son is just starting out on viola and playing dreadfully out of tune, so last week I got out my accordion and played along with him so he could match pitch. The funny thing is that I cant read alto clef, so what I seem to have been doing was finding the starting point and then guessing intervals based on the space between notes on the staff.
If you think that seeing intervals or hearing intervals better might help with your playing, I would recommend an app called Perfect Ear which includes both kinds of drills.