I've known this for over a decade... My piano teacher instructed me to do that.
To learn any piece by heart, never start at the same measure, play voices separately, combine different voices, sing together with it, play it backwards (measure n then measure n-1 + measure n, then measure n-2 + measure n-1 + measure n...), you can do this with bigger sections as well, change tempo, etc. I still remember how to play my 4-voice Bach fugue even though I've stopped playing the piano for years now. I tried this with text and public speaking too and it works.
Can confirm this is widely known within music pedagogy.
However, quite a few of my peers thought it was "stupid" and just practiced the same piece over and over, at the same tempo, without ever stopping and working on the hard parts.
After several years of music, there was a pronounced difference between those who practiced effectively and those who merely repeated their mistakes.
Perhaps a study like this could convince future students that it's worthwhile.
To learn any piece by heart, never start at the same measure, play voices separately, combine different voices, sing together with it, play it backwards (measure n then measure n-1 + measure n, then measure n-2 + measure n-1 + measure n...), you can do this with bigger sections as well, change tempo, etc. I still remember how to play my 4-voice Bach fugue even though I've stopped playing the piano for years now. I tried this with text and public speaking too and it works.
I thought this was widely known...?