A lot of my posts here are about alternatives to the traditional lecture-oriented classroom. Based on that, and on somewhat testy comments like these that I leave lying around the internet, you might get the idea that I am firmly anti-lecture. But that’s not entirely true. There are times and places where lecture works quite well, even better than the alternatives. Here are a few purposes for which I think lecture is well-suited:
- Modeling thought processes. The benefit of hearing an expert learner lecture on a subject is that, if the lecture is clearly given, the audience can gain some insights into what makes the expert an expert. A good lecture does more than convey facts or put problems on the board -- it lays bare the cognitive processes that an expert uses to assimilate those facts or think his or her way through those problems.
- Sharing cognitive structures. Lectures provide the important opportunity for the lecturer to share the mental models and internal cognitive frameworks that worked for him/her when he/she was learning the content. For example, when I took Calculus as a high schooler, I learned the Quotient Rule using the little ditty “Ho D Hi minus Hi D Ho over Ho Ho” and I still cannot perform the Quotient Rule by hand without singing that to myself. I share that whenever I teach Calculus and it works with students -- and it’s not something they would necessarily have come up with on their own.
- Giving context. Good lecturers know more than just their subject material. They know the context in which that content sits and how the material relates to other things -- things that a novice learner might not think about, just because he or she is a novice. Lectures are good places to learn some things from people with a broader set of experiences than you have.
- Telling stories. Stories from popular history or culture or from the professor’s own life are a kind of cognitive structure that help students to relate to the course and see the course content in a different way. For example, students learning logic have trouble with the notion that a conditional (“if-then”) statement is actually considered true if the hypothesis (the “if” part) is false. So I tell a story about promising my kids ice cream if they finish their dinner. If they didn’t finish their dinner but I got them ice cream anyway, it doesn’t make me a liar -- so my “conditional statement” was still true. This connects somehow where truth tables don’t.
Notice that what I don’t include in this list is the one thing that lectures seem most commonly used for: information transfer. In fact lectures, while effective at “covering material”, are terrible for information transfer from the student’s point of view. There are serious problems with retention and recall of information given in a lecture even if the lecture is rhetorically solid -- and this is to say nothing about the disconnect between the length of the average lecture and the average human being’s attention span. Resorting to a lecture because I need to “cover material” is just an admission that I didn’t design my course well. If that’s all the lecture is for, put it online so students can at least pause and rewind.
Notice also that I do not count whether a lecture is inspiring or not. No doubt many lectures are inspiring, but being inspired and being taught are not the same thing, and just having one’s thoughts provoked doesn’t mean that one has interacted with the lecturer in any real way. I am inspired by many of the TED talks and sermons I hear, but it doesn’t mean I have learned anything. I had a pastor once who was unfailingly inspirational -- and I couldn’t remember a single bit of what he preached on, nor could I give even a coherent outline of the sermon, within two hours of church being over.
But while running an entire class in the lecture format is probably not best for students, lectures do have their place, and when it makes sense to give one, we should do so with clarity, organization, and rhetorical skill. We ought to aim for balance, with lecture and active work combining together to produce as rich a learning environment as possible.