It would not be possible to convey in a brief blog post the test lesson I gave this morning to a young man, not a facile reader but with an extraordinarily precise ear. The lesson was inspired by a demonstration at the ICMPC conference of the most frequent errors made by young piano students. That piece, one of my favorite examples of hidden complexity, was given as a prime example of the student errors.
My student proceeded as he has been encouraged to do, by playing the black key in the key signature before sounding the notated pitches. As a result he played a wrong note, not the one in the conference presentation, but an "error" in the corresponding spot in the first measure -- a far more interesting and musically relevant error.
My philosophy about errors is that people, especially children, do not make them mindlessly, as the scholars would have had us believe. My position is that errors signal extraordinary departures from expected tone logic.
My student's error proved me right. In attending to his error and straightening it out I learned a whole dimension of the piece that had previously escaped my attention.
Let's hear it for the vitality of musical elements at every level: I mean e v e r y level.