teacher understanding of student understanding

Hamel's piece helps me envision the kind of research I might undertake on "reading."
I also love the fact that Hamel brings up Gadamer, a literary theorist whose work I have just recently rediscovered for myself and who thinks in really interesting and productive ways on what it means to understand something--anything really, but particularly a literary text. 
Gadamer introduces the concept of "Horizon."  We each understand a text from our point of view, beyond which we are unable to see.  In other words, what we can see or understand is shaped by where we "stand."  Gadamer argues that the inevitably circumscribed nature of our understanding is not a disadvantage or advantage, but simply the only way in which we can understand another text (or another person).  Understanding then means that we use our biases and pay extra attention to the moments when our biases or preconceptions are challenged.  From a "hermeneutical" point of view, it's important to be attentive to the places where we encounter phenomena or behavior that don't seem to make sense  or that cannot be immediately subsumed within our way of understanding.  At such moments, we are compelled to adjust our horizon in relation to "other possible horizons," and our consciousness changes.  Thus Hamel writes:

"Studying teacher understanding of student understanding, then, ... is less a matter of objectifying or testing teacher's partial knowledge in relation to a research base on student understanding, although attention to research can be both useful and powerful.  To understand understanding involves, instead, richer interaction with teachers' starting points in thinking about students, and attention to ways in which teachers can identify their own horizons in relation to other possible horizons" (52).

So Gadamer is interested in understanding understanding and that's what Hamel's research project takes on as well.