I think the biggest thing I’ve learned this year is this: if students aren’t paying attention and haven’t prepared a space in their brain for new knowledge to fit into–or in other words, if they themselves haven’t asked the question that is about to be answered–then they can move through a discovery exercise and not take anything away from it just as easily as they can hear a lecture and not take anything away from that.
Work in Pencil 
I think you’ve hit the nail on the head. Receptivity is the fundamental prerequisite to learning. And that means feeling comfortable enough to let one’s guard down and not have one’s defense mechanisms on red alert during a discovery exercise.
Even though I have long since gotten over my own discouragement issues and become a successful math learner, I have seen how quickly my old habits of discouragement can still snap back into place in a discovery situation. Rather than risk being humiliated, I have noticed my conditioned habit of “hiding” — creating a surface appearance of following along and participating in the activity, but knowing deep down that my inner defenses are protecting me against humiliation in the social situation of the group activity. My defense know that I will go back over this activity and material later, in the privacy of my own mind, where I don’t risk the embarrassment of being seen as clueless in the face of my classmates.
We — and the literature — give short shrift to the primal power of fear and discouragement in the face of group work as a social situation (the idea of milieu, Brousseau, 1997). I believe this is a much bigger issue than the experts understand.
Elizabeth, you are pointing at a different and probably more important issue than what I had in mind. The challenge of getting around the brutally strong affective filter you describe is one of the main things that drew me back into teaching. You’ve probably already read my favorite writings on this from last summer by Dan and by Ben.
I am thinking about the comparatively mild effect (mild, but still devastating to learning) of being required by a teacher to think about something that has not yet piqued your curiosity. When I am required to engage with things I’m not curious about, I go through the required motions, and learn little. Now, of course, I try instead to get curious about whatever life puts in front of me. But now, of course, I’m 42, not 17. What I learned this year is that inquiry-based methods don’t defeat this if they haven’t somehow programmed in a chance for students to ask their own questions and make the connection from those questions to what they are doing in class.
[…] Goldner writes that students must have “prepared a space in their brain for new knowledge to fit into” — that they must have found some questions that they care […]
[…] whether or not a student genuinely goes after a question comes down to whether or not the student makes the question her own. And I’m finding it slow going, as a beginner, to do what Lockhart describes in the same […]