I'd describe at least one of the factors as "play". "Play" to get to know the system you are trying to learn. This knowledge than helps with the specific task.

I'd describe at least one of the factors as "play". "Play" to get to know the system you are trying to learn. This knowledge than helps with the specific task. Given the study I assume a different mechanism coming in to play also: If you try to play a musical piece on an instrument teachers will advise you to practice as slow as needed, not to make a single mistake, that could end up being learned. It's like trying to correct yourself on word you mangled up while speaking, you'll be so fixated you immediately make the mistake again and again. This memory effect might have been countered by the variations in the study. (I posted the same thing elsewhere, but as a comment of the furthest down top-level comment I doubt it will be seen there)