Harvard experiment reveals the psychological grip of lectures
From The Hechinger Report
By Jill Barshay
March 14, 2022
The research evidence is clear. Learning by trying something yourself is superior to passively listening to lectures, especially in science. It’s puzzling why more university professors don’t teach in this more hands-on, interactive way.
Logan McCarty, director of science education at Harvard University, is a prime example. Ten years ago, he told me, he was aware of the anti-lecture studies dating back to the 1980s. But he continued to lecture. Indeed, his title at Harvard was and is “lecturer.” He also happens to be very good at it. A former opera singer, McCarty has a flair for drama and is a natural performer. When I interviewed him by Zoom, his blue-violet hair was styled vertically like a DreamWorks troll (the adorable kind). He makes the intricacies of static electricity comprehensible and fascinating to lay people. Frankly, I would listen to him read the phone book.
But he changed his classroom approach after 2014, when Canadian Louis Deslauriers joined the physics department. Deslauriers is a proselytizer for teaching by doing, what he calls “active learning,” and promised to show McCarty how to do it. McCarty was a convert.
The two scratched their heads about why scientists – who teach the scientific method to their students – weren’t heeding the science themselves. So they conducted an experiment together where they each taught both ways and studied what happened.
Half the students in introductory physics classes were randomly assigned to learn the concept of static equilibrium the traditional way through lectures. The other half was instructed to solve sample problems on static equilibrium without any explanation by working together in small groups. McCarty and Deslauriers, in their respective sections, roamed the room asking questions and offering assistance. After the students attempted each problem, the instructors showed the solution. In total, the instructor talked for only half of the lesson time.
For the next class, the students swapped. The lecture students learned about fluids through problem sets first. And the active learning students listened to a long lecture on fluids.
At the end of each lesson, students filled out surveys about their perceptions of the class and completed a 12-question multiple choice test to demonstrate their knowledge. As expected, students mastered the material more when they were actively learning regardless of whether McCarty or Deslauriers had been their instructor. McCarty’s students did as well as Deslauriers’; it didn’t seem to matter if they had the superstar lecturer or not.
But the fascinating outcome was that most students felt just the opposite, that they had learned more in the lecture. The lecture students more strongly agreed with statements such as “I enjoyed this lecture,” “I feel like I learned a great deal from this lecture,” “Instructor was effective at teaching,” and “I wish all my physics courses were taught this way.”
To confirm, McCarty and Deslauriers repeated the experiment the following semester and got the same results. Almost 150 Harvard undergraduates agreed that lectures were more enjoyable and easier to follow, but they were deluding themselves that they were learning more that way.
“When students hear a lecture from a superstar lecturer, they feel, ‘This is good. I am learning.’ But an hour later, they’re not going to remember it,” said Deslauriers. In other words, the feeling of learning is misleading.
The results were published in a 2019 article, “Measuring actual learning versus feeling of learning in response to being actively engaged in the classroom,” in the Proceedings of the National Academy of Sciences, the journal of the National Academy of Sciences.
In follow-up interviews with some of the students, researchers heard the students complain that active learning felt “disjointed” and they didn’t like the frequent transitions from group work to instructor feedback. They were worried that their errors during class wouldn’t be corrected. Generally, they felt frustrated and more confused. (Interestingly, none of the students complained about group work itself even though conventional wisdom suggests that students often don’t like it.)
Two things appear to be going on here. When you’re listening to a great expert explain something well, it’s easy to mistake the speaker’s smooth, easy delivery for your own understanding. If you’ve ever watched a great cooking show and then stumbled to make a béchamel sauce at home, you’ve experienced this. Students often think they’re following along in class, but at home, they don’t know how to do the homework and they struggle in the course.
The second part of the explanation is that real learning is hard work and it often doesn’t feel good. When you’re struggling to solve a problem in an active learning classroom, it may feel frustrating. Making mistakes and getting feedback to correct misunderstandings is where the learning happens.
It’s also more challenging to teach this way. “As an instructor, I’m adapting what I’m saying on the fly to what I see when they’re working on the problem,” said McCarty. “So I’m not giving a canned lecture. And that makes it a little bit like a high wire act. But it’s also definitely more cognitively engaging for me because I have to decide in the moment, ‘Okay, I have five minutes to talk about this question, what are the most important things for me to say?’”
I was captivated by this study because I think it not only explains why active learning isn’t more popular in college classrooms, but it also helps to explain why teachers, students and parents often reject the conclusions of well-designed educational experiments. We trust our instincts and gut feelings to tell us when we’re learning, but we don’t know what actual learning feels like. (This study should also make us more skeptical of the veracity of student evaluations, but that’s a different topic.)
I am a huge fan of lectures. They inspire me. When I look back on my undergraduate years, I wouldn’t trade my best professors for more time spent on problem sets in class. McCarty and Deslauriers agree that not every course should be taught through active learning. In physics classes, the goal is to get students to solve the kinds of problems that physicists encounter so it makes sense to spend class time practicing this.
“Sports and music instruction make this really clear,” McCarty said. “Watching [Roger] Federer play tennis can get you really excited about tennis, but it’s not going to make you a great tennis player.”
McCarty also co-teaches a class with a biologist called “What is Life? From Quarks to Consciousness.” Inspiration is the goal. Here, McCarty spends much more of his time lecturing. I’m jealous of his students.
Photo: CollegeData
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