Rob Knop talks about a great teaching moment: A student who refused to just smile and nod:
I was very grateful for that student. You see, when professors ask, “do you understand that?”, it’s not a test. It’s not the professor trying to catch the students up in admitting to being confused, it’s not the professor trying to sepearate the good students (Hermiones) from the bad students, the latter being the ones who will admit to struggling with the material. When we ask the question “do you understand that?” we ask it because we want to, yes, find out if the students understood what we just did.
Amen, brother.
In grad school, I had to take some undergrad math courses. In one, I asked the grad student teaching the course a question, he answered, and I said, “That makes sense.” For that little exchange he remembered me several years later when our paths crossed on campus.
In my first work as assistant I have a student always nodding. This reassured me that everyone was understanding the problems and I kept a fast pace until I started to suspect about the nod. Of course it was a trap: at the end, this studend did a completely wrong examination, and I probably it caused some of the students to fail too, because he induced me to this fast-speed mode.
In the seminar room I know one of two people with problems in the back, so they are forced to stay erect feigning attention. At least they do not nod.