Skinner's statement, that all human action is the direct result of conditioning seems to prove itself in the practise of musical instrument learning. As a non-professional in the field of educational psychology, I can only draw on my 18 years of personal experience as a music student.

Learning a musical instrument takes years of consistent and devoted practice from a very early age. During that time student takes 1-1 lessons with a teacher and inevitably forms some kind of bond with him, taking over some of his philosophies and understandings about music making in general.

Usually, students who had great relationships with their teachers are more likely to pursue their career in this field, while students who had teachers who were too demanding end up giving up the instrument saying that it was not for them or that they could not understand how to practice it. I experienced that instrument playing is a skill-based activity and without constant practice it is hard to get good results and perform successfully. For that reason some teachers push their students to practice more and more, constantly giving them a more challenging repertoire. If a student is always pushed to perform better, not awarded after performing well enough, and constantly punished after unsuccessful performances, the motivation to study further decreases which results in antipathy towards music making. (This is better explained by Ryan and Deci in Self Determination Theory).

On the other hand, if a teacher is encouraging and supportive, it might give great results because a student is getting enough motivation to study music.

Of course, there are exceptions in every case, but these are my general thoughts on teachers' role in students' learning process, and I think that a teacher definitely plays an important role of a nurturer that might affect students' career choices when it comes to it.