I recently found out about social learning theory as expounded by Albert Bandura at Stanford University. It offers a psychologist's view of the approach to teaching at which I have arrived after decades of experimentation. The essence of it (in my words, of course) is that we learn by modeling. When there is no leveling according to age or skills each individual within group of learners will pick up characteristics from the others, usually at a depth that far exceeds superficial skills. In my class, which ranges from a blind autistic individual to some superior intellects, the students apparently respond to one another's motivation. The integrity of the learning is extraordinary as each student surpasses his or her own expectations.
Bandura does not address music in his study. The essential skill that I as teacher model is not playing so much as listening. As I listen intently to each student, so they learn to listen intently to one another and to themselves, from many musician's standpoint, the hardest skill to learn. As for the musical standard, it is set by the composers, who seem to be included in our community of human openness.
Never have I seen young people go so far with their ability to comprehend works of the masters.