In Defense of Lecture

Lectures have a black eye on college campuses today.  We’re told that they are useless, and that they are ineffective with out “explicit constructionism.” We’re told to use active learning techniques in lecture, like clickers.  I’m realizing that there’s nothing wrong with lecture itself, and that the psychology results tell us that lectures should be a highly efficient form of learning.  The problem is that there is an interaction between lecture as learning intervention and our students. That is an education (or broadly, a learning science) result, and it’s important to note the distinction between education (as instructional engineering, as psychology-in-practice) and psychology.

I just served on a Psychology Masters thesis committee.  In 2009, Micki Chi published a paper where she posited a sequence of learning approaches: From passive, to active, to constructive.  She suggested that moving along the sequence resulted in better learning. While her paper drew on lots of dyad comparison studies between two of those styles of learning, nobody had compared all three in a single experiment.  This Masters student tested all three at once. He put subjects into one of three conditions:

• Passive: Where students simply read a text on ecology drawn from a Sophomore-level textbook.
• Active: Where students either (a) highlighted text of interest or (b) copy-pasted key sections into “Notes.”
• Constructive: Where students either (a) created self-explanations of the text or (b) created questions about the text.

He had a test on the content immediately after the training, and another a week later.  Bottomline: No difference on either test. But the Masters student was smarter than just leaving it at that.  He also asked students to self-report on what they were thinking about when they read the text, like “I identified the most important ideas” or “I summarized (to myself) the text” (both signs of “active” cognition in Chi’s paper), or “I connected the text to ideas I already knew” or “I made hypotheses or predictions about the text” (“constructive” level).  Those self-reported higher-levels of cognitive processing were highly correlated with the test scores.  Micki Chi called these “potential covert activities” in these kinds of studies.  That’s a bit of a misnomer, because in reality, it’s those “covert” activities that you’re really trying to engender in the students!

The problem is that Georgia Tech students (the subjects in the study) are darn smart and well-practiced learners.  Even when “just reading” a text, they think about it, explain it to themselves, and summarize it to themselves.  They think about it, and that’s where the learning comes from.  All the “active learning” activities can help with engendering these internal cognitive activities, but they’re not necessary.

Lectures are a highly-efficient form of teaching.  Not only do they let us reach many students at once, but they play upon important principles of instructional design like the modality effect.  Hearing information while looking at related pictures (e.g., diagrams on Powerpoint slides) can allow for better learning (more information in less time) than just reading a book on your own.  Coding live in lecture is a “best practice” in teaching computer science. I don’t dispute all the studies about lectures, however — lectures don’t usually work.  Why?

We add active learning opportunities to lectures because students don’t usually learn that much from a 90 minute lecture. Why? Because it takes a lot of effort to keep learning constructively during a 90 minute lecture.  Because most students (especially undergraduates) are not great learners.  This doesn’t have anything to do with the cognitive processes of learning.  It has everything about motivation, affect, and sustained effort to apply those cognitive processes of learning.

Maybe it has to do with the fact that most of these studies of lectures take place with WEIRD students: “Western, educated, industrialized, rich, and democratic cultures.”  A recent study in the journal Science shows that many of our studies based on WEIRD students break down when the same studies are used with students from different cultures.  Maybe WEIRD students are lazy or inexperienced at focused learning effort. Maybe students in other cultures could focus for 90 whole minutes.  In any case, I teach WEIRD students, and our studies of WEIRD students show that lectures don’t work for them.

There’s another aspect of this belief that lectures don’t work.  I attended talks at education conferences lately where the speaker announces that “Lectures don’t work” and proceeds to engage the audience in some form of active learning, like small group discussion.  I hate that.  I am a good learner.  I take careful notes, I review them and look up interesting ideas and referenced papers later, and if the lecture really captured my attention, I will blog on the lecture later to summarize it.  I take a multi-hour trip to attend a conference and hear this speaker, and now I have to talk to whatever dude happens to be sitting next to me? If you recognize that the complete sentence is “Lectures don’t work…for inexperienced or lazy learners,” then you realize that using “active learning” with professionals at a formal conference is insulting to your audience.  You are assuming that they can’t learn on their own, without your scaffolding.

When I was a student, I remember being taught “learning skills” which included how to take good notes and how to review those notes. I don’t know that those lessons worked, and it’s probably more effective to change lecture than to try to change all those students.  We do want our students to become better learners, and it’s worth exploring how to make that happen.  But let’s make sure that we’re clear in what we’re saying: Lectures don’t work for learning among our traditional American (at least) undergraduate students.  That’s not the same as saying that lectures don’t work for learning.