As a community college prof, I think a lot about what we don't teach students because we assume it's common knowledge.
A few years ago I was most of the way through a lecture/discussion on the New Deal when a student raised her hand to ask me to explain the difference between Democrats and Republicans.
I'd taken that baseline knowledge as a given, and built on a foundation that assumed it. As a result, she hadn't been able to get real purchase on anything I'd said because she was working by inference.
And I know I'm going to get people tweeting "How could anyone get to college and not know that?" at me. Dude. I'm explaining how. THIS is how.
I've since realized that if you do it right, starting from bedrock can be great pedagogy for both beginning and advanced students, because you wind up interrogating your own assumptions as well as theirs.
I'd add that it's often the smartest, most confident students who ask the most basic questions, because they're not afraid of being humiliated if they ask.
I had a student once call me over during a quiz to ask for a word she'd heard me use in class—took a little back and forth to figure out the word was "Europeans." She was running an A in the course.
And of course we as profs often don't talk about these moments, because we're afraid of admitting our own ignorance and failings.
I hesitated before telling that Democrats/Republicans story, because it's a story about me screwing up. But telling stories about screwing up is how we help each other become better teachers.
(I've wound up quote-tweeting replies to a lot of responses to this thread, so if you don't follow and are interested in the discussion, check my timeline. Also, hi!)
Since this thread is still getting attention and the spinoff threads are slipping further down my timeline, here's a link to the meatiest one so you don't have to go searching for it if you're interested in more...
