We all know the situation well, which is why "Anyone, anyone?" resonates so well as comedy. The professor asks the class for questions, no hands go up, the lecture proceeds. The young professor has ambitions to teach a highly interactive course, yet no one speaks up, and frustration ensues. What went wrong? Why won't anyone raise a hand?
To my mind the answer is quite simple, but it has taken me more than 15 years to figure it out. The problem is that asking a question in a lecture hall or even a class of 10 students, represents a high-stakes proposition for the student. Worse yet, the proposition is low-reward. Thus, a student not asking questions in class is a student acting rationally to the odds presented them.
I'll flip this coin. If you get it right, I pay you a buck. If you get it wrong, you owe me $100. Wait, why are you walking away?!
Smart money walks away.
So what is the high-risk proposition? As a professor I'm requesting that a student to ask a question and thereby admit ignorance. We say there are no dumb questions, but take an extreme case of asking about a basic algebra concept in the middle of a General Relativity course. Or asking a colloquium speaker a question that was covered on their first intro slide. No dumb questions? Yeah right! Students know that's bullshit. There are plenty of really bad questions. In fact, there are far more bad questions than good. So by not raising their hand, a student is folding in a situation with far more risk than reward, and an upside-down odds ratio.
Speaking of risk, the student not only risks asking a dumb question in the presence of a professor, but they also risk asking it in front of all their classmates. In a class of 10, this is bad enough. In a lecture hall of 200? Yikes! It's just like one of my favorite movie scenes (WARNING: video below not safe for work or kids):
And how about the prospective reward? The student asks a question that is on-point. Bravo! The prof may say, "Excellent question," gives the answer, and move on with the lecture. However, in the student's mind, this is par for the course. The student is supposed to have done the background reading, understood that background, and followed the lecture up to this point. But if a student has done all of this when it is expected, then how much of a compliment does "Excellent question" represent? As Chris Rock said, "That's what you're supposed to do, you low-expectation-having [explicative]! What do you want, a cookie?"
By the way, this recently happened to me during a lecture at MIT. I saw that Jim Kasting was giving a EAPS seminar talk, and I was fortunate to be able to attend. At one point he was talking about oxygen-rich atmospheres and by analogy referred to one of the Apollo accidents resulting from a fire in an oxygen-rich environment. He couldn't remember which Apollo mission it was, and I blurted out "Apollo 13." That's what I get for watching too many movies. Wait, that's what I get for taking bad odds.
There's the problem. The best solution that I've come up with is to break the class into smaller groups and get them talking together, and asking questions on a more intimate level. Asking a dumb question in a room of hundreds is a proposition one should almost always walk away from. But asking your peer something basic is what we do all the time, but usually in private. So if you'd like your class to ask questions, pause the lecture, have them turn to another student nearby and tell them something they don't quite understand. The other student can then explain it, or as it frequently happens, admits that they don't understand it either At that point, both students can ask the question together, with the full confidence that their question isn't so dumb and that that they are not the only one lost.
I once tried this out in the middle of a colloquium. It resulted in so many good questions that I had to cut the impromptu Q&A session off so I could get to the end of my talk. Meanwhile, the times when I've stopped in the middle of a colloquium and asked for questions, I typically only get them from the sage astro-wizard sitting in the front row.
The next time you teach a class, which many of you are doing this time of year, give this risk-mitigation strategy a try. I think you'll be pleasantly surprised with how interactive your classroom or lecture hall suddenly becomes.