Does Teaching Require Sacrifice?

I was in the doctor's office yesterday reading an old copy of Smithsonian and came across a fascinating article on chimpanzee behavior. While tool use has been observed many times in many contexts, learning is transmitted through an apprenticeship model where younger chimps observe older ones at work and then figure it out through trial and error on their own. What has never been observed is chimpanzee teaching. Technology is transmitted passively, never actively.

For a behavior to be considered to be an instance of teaching, primatologists contend that it has to satisfy three criteria:

(1) It has to be goal-directed on the part of the teacher with the goal being the acquisition of knowledge or a skill by another.

(2) It has to have an assessment element, that is, there must be evidence of reward or positive sense given for good work, correction or negative feedback for mistakes, or some sort of corrective action when the learner is off-track.

(3) There has to be some sort of price or loss for the teacher. The behavior must keep the teacher from getting the pine nut to eat him/herself or it must keep him/her from being able to do something else that would be more personally beneficial.

As a teacher and a primate myself, the third criterion struck me as odd. I began to wonder whether I satisfied that condition as a collegiate instructor. Do I suffer at all from teaching? I suppose there is other stuff I could be doing, but frankly teaching is one of the things I enjoy most. For some reason, they pay me for doing it, so rather than a loss it is a gain -- now, sure, there's probably something to be said about philosophers' salaries, but relative to the philosophers' work load (I can't believe I just typed that phrase)...

It certainly doesn't seem to fit the graduate student/thesis director relationship, but perhaps that is to be considered indentured servitude instead of teaching. While that was in part meant to be sarcastic, it does seem appropriate to rule that out as teaching. The condition does seem to come from the intention of separating out training underlings to do your bidding from the act of teaching which should be more purely other-directed, that is, an activity undertaken for the sake of the learner, not for the sake of the teacher.

But is that really necessary? Do I have to give a darn whether the class members are improved? Can I be teaching in a completely selfish way? Suppose there's a book I've always wanted to read and I know that I'll understand it and appreciate it better by breaking it down in a fashion that looks just like a lecture and classroom discussion? Did I teach the book if I gained rather than sacrificed?