While the student is trying to do a difficult exercise on the instrument, music teacher will often fall back on this advice: Slow down. And, while the advice is great and most of the time exactly what is needed, it is not sometimes possible for the student to follow it. For one good reason: pain.
I know it seems a weird statement on my part but slowing down obliges the mind to analyse the data it is processing, more than that, the body has to consciously move at a different pace and more accurately at a very inorganic pace, and, maybe the strangest ingredient to throw in the mix, is that the brain doesn’t hear it slower. After all, the student has heard from the teacher what the pattern should sound like. It has a certain flow that allowed his mind to understand it. But, in essence, the teacher is asking the student to disunderstand it, if I may say. So, against the advice “Slow down” comes crashing the whole being of the player and, more often than not, he messes up badly,he stops, and he starts again at the initial bright speed he tried it in the first time. Which gets the teacher annoyed.