Friday, January 6, 2012

Don't lecture me

Another great radio piece by Emily Hanford (I caught the end of what I assume was just part of it on the NPR afternoon news show on Sunday) here (audio and transcript both there). She reports the research on the effectiveness of lectures in prompting actual learning: not much. Anyone reading who lectures must listen to/read it.  A long excerpt (followed by some comments):

Lecturing was the way just about everyone taught introductory physics. To think there was something wrong with the lecture meant physics instructors would "have to really change the way they do things," says Hestenes. A lot of them ignored his study and kept teaching the way they always had. They insisted their lectures were working just fine. But Eric Mazur was unusual, says Hestenes. "He was the first one who took it to heart." Mazur is a physics professor at Harvard University. He came across Hestenes's articles in 1990, five years after they'd been published. To understand why the articles had such a big impact on Mazur you have to know some things about his history. Mazur grew up dreaming of becoming an astronomer.

"When I was five years old I fell in love with the universe," he says. "I tried to get my hands on to every accessible book on astronomy. I was so excited by the world of science." But when Mazur got to university, he hated the astronomy classes."It was all sitting in the lecture, and then scribbling down notes and cramming those notes and parroting them back on the exam," he says. "Focusing on the details, focusing on memorizing and regurgitation, the whole beauty of astronomy was lost." So he switched to physics. It wasn't as heartbreaking for him to sit in a physics lecture and memorize things. Mazur eventually got a Ph.D. in physics and a job at Harvard University. Like most Ph.D.s, Mazur never got any training in how to teach.

"I just mimicked what my instructors had done to me. I think that's what we all do. So, I lectured." Turns out he loved lecturing. It's a lot more fun being on stage delivering a lecture than it is sitting in the audience watching. And that's exactly what a lecture is, says Mazur: a performance. He decided to make it fun. "Thanks to the setup we have here at Harvard, it was very flashy, like a Hollywood show," he says. "Attention-grabbing demos, me shooting through the lecture hall in a rocket car."Mazur's students apparently loved it. His classes were full and he got great evaluations from the students at the end of every semester. "For a long while, I thought I was doing a really, really good job," he says.

Then Mazur read the articles by Hestenes and Halloun. Mazur's first instinct was to dismiss the results. The test covered such basic material; he was sure his students were learning this stuff. But what if they weren't? How boring it would be to learn physics and never really understand the fundamental concepts that make physics so fascinating. Mazur thought back to his own experience with astronomy; if his students were just memorizing information and solving problems, he had to know, and he had to do something about it. So he gave them the FCI, and he was shocked. "They didn't do much better," he says. "In fact, when they looked at the test that I gave to them some students asked me, 'How should I answer these questions? According to what you taught me, or according to the way I usually think about these things?' That's when it started to dawn on me that something was really amiss."

I am a culprit in the promulgation of the lecture. But this comment by Alan Bostick, alongside the critical comments of Keith M Ellis, haunted me for a long time. I now follow Bostick;s advice whenever possible with, in recent experience, quite spectacular results. I find, though, that asking a single undergraduate to prepare a lecture, is really too much pressure. That may be because they are never asked to do so, but they aren't so I have to live with that. I have usually asked them to prepare in pairs; this past semester, mainly due to my own incompetence, I assigned them in 3s, which seems to have been ideal. In my class of 24 students, not one of the 8 classes which were run by students was less good than the average class run by me, and many were far better than my average (of course, I contributed in discussion, a lot I'd like to think, and I did select the for the first presentation a group of students whom I thought, rightly, would set a standard that would press the others to perform well).

Of course, in a class of 160 I cannot assign lectures to all the students. But I use the guidance that almost nobody can concentrate on even my lecturing for more than 20 minutes, and so break up the classes as much as possible with (I hope well considered) discussion questions, often starting out by asking them to talk to each other, then getting them to discuss in the larger format. I know this doesn't work for all the students, and I know a lot of good students find the ramblings of their peers frustrating, so I do still lecture a fair bit, and exercise a good deal of control in the discussions.

My suspicion is that there is a small subset of students who can and do concentrate for more than 20 minutes; in fact they can concentrate for hours. I was one of those, at least when the lecturer met some low threshold of quality. The reason that many academics in the US system think their own lectures are effective is that they were in that small subset (and their belief is never tested, since they assign the assessments, which are not designed to test their belief in their own effectiveness...). We select for people who are like us.

(Crossposted at CrookedTimber)


  1. I'm curious, have you read Paulo Frere's book (which Alan Bostwick mentions)? If so, did it offer any useful correctives?

  2. Harry, do you know what your students thought about how much they learned from their peers' lectures (as opposed to yours)?

    Also, though I haven't looked at it yet, the NPR story's link to Monash's Peer Instruction in the Humanities Project looks useful.

  3. Lectures can be very useful as a threat.

    I'm lucky enough that most of my teaching is in small groups. I like to run classes seminar style - I set some reading, and then we discuss it in class. But frequently, it becomes apparent that none of the students have done the reading. On one occasion, I was so frustrated that I simply took out my own copy of the article, and read it out loud while they listened.

  4. @Ben -

    That's pretty funny (well, you know, not that the situation is funny). How long was the article?

    @All -

    I tend to be a bit ambivalent about the whole thing, to be honest. There's a place for lecturing inside of a discussion course, I think. The problem is when lecture becomes the primary vehicle of delivery. I can't imagine a philosophy class in which I was expected to just sit there and listen for 50 min. At the same time, undergraduate students -- especially in general education philosophy classes -- really have a hard time understanding the material. As a result, mere discussion is really not helpful to their learning. In my view, discussion should be used up until that point where you know that the critical mass simply doesn't understand the lesson on a fundamental level. At that point, it's time to hit the blackboard and do some lecture, and only until the point where they seem to be getting it again.

    So for me, it's just not black and white. But are there really people in non R1 environments who stand up in front of the room and lecture for 50 min?

  5. Chris - I think the article was 20-30 pages. I wouldn't have minded if they hadn't gotten to the end, or had problems understanding it, but they admitted that they hadn't read a single word of it.

  6. I taught a philosophy elective this past term in which I had both philosophy majors and students who had taken no or very little philosophy, and, as usual, I tried my best to lecture little and emphasize group work, student's contributions, etc. A few weeks in, one of my advanced philosophy students came into my office to ask me to lecture more because she felt she had nothing to learn from the students who didn't have the philosophy background she did and that she had taken the class to learn from me. I was sympathetic, as I also was one of the students who relished a good lecture, but I did try to explain to her that I wasn't being fair to the other students if I lectured all the time. She acknowledged my point, though I did try after that to include a bit more lecturing. Perhaps this was a problem with having a class with such diverse philosophy backgrounds and, more likely, I didn't achieve the right balance, but I think she voiced a frustration common among advanced students with peer learning. And I still haven't found a better way to explain, or justify, the benefits to such an approach than fairness.

  7. Jennifer raises an important point about peer-learning. Students are not usually ready to teach - if they were, why would they need us?

    I find the following format helpful. I ask students to give presentations as a preliminary to writing a paper. So the student is presenting a work in progress. I don't grade the student for their presentations: that takes off the pressure. If the presentation is poor, it doesn't matter, and that knowledge keeps them relaxed. I do grade the other students in the class for the way they respond to the presentation - a helpful response is one that enables the presenter to produce a better paper: "You could also have mentioned..." "Yes, but someone might object..." Finally, I offer my own response and advice.

    So, when a good student gives a good presentation, the other students learn from it. When a bad student gives a poor presentation, the smart students at least know they are getting credit for suggesting improvements.

    If a poor presentation is followed by unhelpful suggestions, the students sense that they are floundering around a bit. At that point, they are motivated to hear a short lecture from me, in which, hopefully, I resolve the problems.

    In my experience, a seminar does not eliminate the lecture. It provides me with information about what the students need to hear, and students with an incentive to listen, because they are looking for a solution to a problem. In that context, a brief lecture (half an hour) can work quite well.

  8. Having also been a member of that smaller subset who feel that they can absorb the lecture, I have a lot of sympathy for their reaction to group work. I found discussions to be unfruitful and classmates to miss the point more often than was meaningful - it felt like time was being wasted and I ended up skipping any tutorial that wasn't compulsory.

    Now that I'm on the other side of the equation, I'm really beginning to question how much of my reaction to the group situations arose from some type of cognitive dissonance. I was certainly under the impression that I was learning more from just listening and 'taking in' the lectures, but the memories that have stuck the longest have been the situations where I had to explain and justify myself to others, make connections between various ideas and arguments, politely evaluate another the point expressed by another human being, etc. This 'higher order thinking' stuff is much trickier to do and requires more risk. I certainly *felt* like I was learning more during the lectures, but without feedback or risk I was more prone to leave my preconceptions unquestioned (similar to the research discussed here:

    In the feedback that I received on my classroom instruction last year, there was a trend that indicated that many students would like to hear less from their peers and more from the teachers. But the work that I saw the groups produce (say, piecing together an argument in a small group) was usually of good quality overall.

    I think that the 'students as teachers' strategy would be a useful one to encourage in our students who would otherwise want more lecturing. One way to justify this to the more advanced students could be pointing out that they won't really know that they know unless they can test it out and explain it to others. I agree with Ben about students not being entirely ready; thanks for the activity suggestion. I hope there will always be a place for teacher-talk in any educational context. But I'm going to try to give students more structure this year (perhaps on questioning skills) and see if that makes any difference to their experience / learning during group work, as I think it can offer challenging and meaningful learning opportunities for everyone.

  9. Harry, this is exactly right:
    "The reason that many academics in the US system think their own lectures are effective is that they were in that small subset (and their belief is never tested, since they assign the assessments, which are not designed to test their belief in their own effectiveness...). We select for people who are like us."

    And it's frankly infuriating when I hear faculty say 'I teach X this way - after all I learned it that way!' That's quite compatible with that being a lousy way to teach X to nearly everyone else! Academics become academics because they are freakishly adept at learning in academic settings - like lectures.

  10. Michael -

    I think it's partially right, but it's not a sweeping truth. As I think many above have indicated, many students ask for more lecture to be incorporated when they are not getting things at more foundational levels.

    They key is not to abolish lecture, but to be pedagogically intentional about why, how and when it is incorporated.

  11. The other thing that can lead students to claim to learn better from lecture is that sitting through a lecture "feels" more like learning to most of them. Particularly the good students. They have come to have particular expectations about what teaching/learning looks like, and when you increase the amount of activity in your classroom you both mess with that expectation, but can also threaten their sense of well being. They are very comfortable with knowing what to do to do well in a lecture-based course, but don't have that same sense when it comes to a different format.

    I think lecture is most useful when it comes AFTER an exercise or activity that makes clear to the students that they don't yet get the material.


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