I’m surprised when I talk to college students and professors these days and hear that lectures are still a common method of instruction. This week, however, I came across two sources that challenge the old tradition. The first was a study of Astro 101 (that is, Introductory Astrology) teaching methods, which explored ways to improve the effectiveness of very large mega-classes sometimes averaging over 1,000 students. The second was an article recently shared by Kim Marshall in his weekly Marshall Memo. Perhaps the tide will soon be shifting, as it should, away from lecturing.
Cutting to the quick, here’s the overview of the study’s findings:
“Classes that spent 25 percent of their class time (or more) using interactive learning strategies averaged more than twice the normalized gain scores as compared to classes that spent less than 25 percent of class time teaching interactively. Furthermore, we found no correlation between student learning gain and type of institution or class size (even in a class of almost 800 students, as we discuss in detail below).”
In this thoughtful Harvard Magazine article, Craig Lambert describes how Harvard professor Eric Mazur, who had been teaching a popular introductory physics for seven years, found out that his success as a teacher was “a complete illusion, a house of cards.” In 1990, he gave his 150 students a simple test to check their understanding of one of the most basic concepts in physics – force – and only a third of them passed. “After a semester of physics,” he says, “they still held the same misconceptions as they had at the beginning of the term.” They could recite Newton’s Third Law and apply it to numerical problems, but when asked about the forces at work when a heavy truck collides with a light car, they mistakenly said that the truck exerts a larger force.
Mazur flailed around for an explanation: “Maybe I have dumb students in my class. There’s something wrong with the test – it’s a trick test!” But in the end he had to face up to the fact that although he had been delivering polished lectures and doing artful demonstrations and getting excellent course evaluations every year, his students weren’t learning the most important things he was supposedly teaching. Mazur went over the conceptual test with his students, trying twice to explain the basic physics principles. No success. Students remained obstinately confused.
Peer-to-Peer Teaching & Discussion
“Then I did something I had never done in my teaching career,” he recalls. “I said, ‘Why don’t you discuss it with each other?’ It was complete chaos, but within three minutes, they had figured it out. That was very surprising to me – I had just spent 10 minutes trying to explain this. But the class said, ‘OK, we’ve got it, let’s move on.’” The magic he had witnessed was peer instruction – those who understood the principles did an excellent job explaining it to their clueless peers. Why were some students so much better at explaining than him? “You’re a student,” he says, “and you’ve only recently learned this, so you still know where you got hung up, because it’s not that long ago that you were hung up on that very same thing. Whereas Professor Mazur got hung up on this point when he was 17, and he no longer remembers how difficult it was back then. He has lost the ability to understand what a beginning learner faces.”
The key to learning, concluded Mazur, is being an active explainer rather than passive sponge. “The person who learns most in any classroom is the teacher. From cognitive science, we hear that learning is a process of moving information from short-term to long-term memory; assessment research has proven that active learning does that best.” The key is taking new information and applying it to real situations, connecting it with personal experiences, projects, and goals, taking personal ownership of it.
Flipping the Classroom
As Mazur began to rethink his lecture-centered approach, he realized that instruction is a two-step process: first, new information is transferred from teacher to learner; second, the learner makes sense of and assimilates the information. “In the standard approach,” he says, “the emphasis in class is on the first, and the second is left to the student on his or her own, outside the classroom. If you think of this rationally, you have to flip that, and put the first one outside the classroom, and the second inside. So I began to ask my students to read my lecture notes before class, and then tell me what questions they have, and when we meet, we discuss those questions.”
Mazur projects these questions onto the screen and students respond with clickers. If 30-70 percent of students don’t answer correctly, he has them find a person sitting nearby who got a different answer and argue about it. After 2-3 minutes, Mazur re-polls the question, and almost invariably, the number of correct answers improves dramatically. Students are solving problems they don’t fully understand, which is just what Mazur wants. “Let’s turn our students into real problem solvers,” he says. “In a real-world problem, you know where you want to get, but you don’t know how to get there… Most tests and exams at Harvard are not like that; they are questions where you need to determine what the answer is… It’s the opposite of a real-life problem, because you know the prescription, but you don’t know the answer.”
Mazur’s students sometimes complain that his tests ask them to solve problems they’ve never encountered before. He tells them, “If you had done a problem of this kind, then by definition, this would not be a problem” – which definitely takes students outside their comfort zone. “It’s not easy,” he says. “You get a lot of student resistance. You should see some of the vitriolic e-mails I get. The generic compliant is that they have to do all the learning themselves. Rather than lecturing, I’m making them prepare themselves for class – and in class, rather than telling them things, I’m asking them questions. They’d much rather sit there and listen and take notes. Some say, ‘I didn’t pay $47,000 to learn it all from the textbook. I think you should go over the material from the book, point by point, in class.’ Not realizing that they learn precious little by that, and they should actually be offended if I did that, because it’s an insult to their intelligence – then, I’m essentially reading the book to them.”
Mazur says the architecture of college lecture halls also works against peer learning. He believes elementary classrooms, with four students sitting at desks facing each other, are far better set up – as long as the teacher assigns a well-thought-out group activity. “That’s how we learn,” he says. “For some reason we unlearn how to learn as we progress from elementary school through middle school and high school.” Mazur is not a fan of student course evaluations; he considers them popularity contests and thinks they should be abolished. “There is zero correlation between course evaluations and the amount learned,” he says. “Award-winning teachers with the highest evaluations can produce the same results as teachers who are getting fired.” What matters is how much students are learning, and that’s not picked up in student surveys.
Preaching to the Choir
Mazur has become something of a Johnny Appleseed for interactive instruction, giving almost 100 talks around the world each year and influencing untold numbers of instructors to change their approach. When he speaks about pedagogy, he asks listeners to think about something they’re really good at and reflect on how they attained a high level of proficiency. About 60 percent of people say it was because they practiced a lot. Strikingly, nobody mentions lectures. Mazur likes to quote Camus – “Some people talk in their sleep. Lecturers talk while other people sleep.” – and he’s on a campaign to get teachers to stop lecturing. “The danger with lucid lectures – of which we have so many on this campus, with so many brilliant people – is that they create the illusion of teaching for teachers, and the illusion of learning for learners. Sitting passively and taking notes is just not a way of learning. Yet lectures are 99 percent of how we teach!” Education is more than just the transfer of information, he concludes. If that were all there is to it, web-based instruction could do the job – sites like Khan Academy. “They have 65 million users,” says Mazur; “it’s a force to be reckoned with. But ultimately, learning is a social experience. Harvard is Harvard not because of the buildings, not because of the professors, but because of the students interacting with one another.”
Terry Aladjem of Harvard’s Bok Center concurs: “The live classroom is still the best medium for a student to truly be known as an intellectual being and to engage with other such beings. You learn from your peers in all walks of life. Students have always hidden in their rooms; social media can keep them in their rooms longer.” The way to coax them out of their rooms and into each other’s minds is to make classroom learning a social experience. Over the last 20 years, Mazur has gathered extensive data on this “flipped”, interactive approach. Among the findings: – Students’ conceptual understanding of physics is three times better; – Students’ long-term retention of factual knowledge has improved significantly. “In a traditional physics course,” says Mazur, “two months after taking the final exam, people are back to where they were before taking the course. It’s shocking.” – The achievement gap between male and female students closes. – Students in interactive courses are much less likely to transfer out of science, technology, engineering, and math concentrations.
“Twilight of the Lecture” by Craig Lambert in Harvard Magazine, March/April 2012 (Vol. 114, #4, p. 23-27), https://harvardmagazine.com/2012/03/twilight-of-the-lecture; Mazur’s book on this subject is Peer Instruction, which is summarized in Marshall Memo 241.