“When I started teaching, I never asked myself, ‘how am I going to teach?’ Which is strange, because that should be the first question you ask yourself when you do something new.” — Eric Mazur, Area Dean for Applied Physics at Harvard University
Premeds are not very kind to physicists. Physics is a requirement for med school, and it's treated with a bit of dread, but mostly indignation. Eric Mazur knew that, but accepted the challenge when he started teaching at Harvard.
Over the next six years, he'd go on to develop an engaging lecture style.
I would go through my classroom on a rocket-propelled cart. I would climb up to the ceiling. It was like a Hollywood show. I would have this big ball swing on a pendulum, and it would swing from my nose across the classroom, and come back. The whole class would gasp. I was a star.
And he got results.
On the dreaded end-of-semester questionnaire, I got 4.5, even 4.7, on a 5-point scale.
The other metric is exam assessment. [My premed students] were able to solve problems that were complicated. Questions I wasn't even sure I could do flawlessly under the pressure of an exam. Like, two stick are lying on a frictionless surface. A puck hits them and the two sticks start to rotate together. Calculate their angular and translational positions as a function of time. No problem for most of these pre-meds.
I started to believe I was the world's best physics teacher. It was an illusion that lasted many years.
Then he came across a study by Ibrahim Halloun and David Hestenes, across the country in Arizona, that attempted to distinguish between memorization and understanding. It opened with a confrontational stance:
Each student entering a first course in physics possesses a system of beliefs and intuitions about physical phenomena derived from extensive personal experience. [...] Yet conventional physics instruction fails almost completely to take this into account.
In other words, students entering university physics courses had "common sense" mental models about how physical objects, the same as any layperson. That mental model didn't change after learning Newtonian theory.
The study had covered thousands of university students across California, New Mexico and Arizona, and the results showed little improvement in students' answers. If you define learning physics as understanding physics around you, no learning was actually happening.
Their research employed a simple test, the same real-world physics problems were asked before a physics course and after. But rather than make them math calculation questions, they were multiple-choice questions based on real situations described in words.
A car and a truck collided head-on on the highway. Was the force exerted by the heavy truck on the light car:
a) larger than the force exerted by the light car on the truck
b) equal to the force exerted by the light care on the truck
c) less than the force exerted by the light car on the truck
Newton's Third Law is that when one body exerts a force on another, the other simultaneously exerts an equal force in the opposite direction. This question tested if someone recognised when Newton's Third Law was happening in the real world.
These researchers showed that it doesn't make any difference whether you ask the questions before the students have had their physics course or after.
"I thought, 'Not my students.' But I'm a scientist. If you make a statement, you better show the data."
So Eric used the test on his students.
And when he did a hand shot up. The question:
"How should I answer this? According to what you taught me, or how I usually think about these things?"
Exactly as the paper predicted, the student was asking if they should repeat what they learned, or use their common sense. They weren't the same thing.
Succes is defined by what the learner becomes.
All along there were signs that something was wrong. For example some students would write in there at the bottom of their end-of-semester evaluation: 'physics is boring' or 'physics sucks' (even though they gave me a high rating ).
I remember at one point, trying to explain to my students something that, to me, was completely trivial. I took two minutes, made some sketches on the board and then said turn around to the class and said and by Newton's Third Law these two forces are equal to each other.
I could see at once from my students faces that they were confused, so I asked if they had a question. They were so confused they could not articulate a question so I erased the board and tried it a different way.
I added equations and after eight minutes of what I thought was an absolutely brilliant explanation, the entire blackboard was covered with equations and drawings. I turned around and the students looked even more confused.
I didn't know what to do.
[But] half the students had given the right answer to that question on a test. So in a moment of despair, I said to them why don't you discuss it with each other?
The quiet, intent stares immediately disappeared as the classroom erupted into conversation.
Imagine you have two students next to each other, John and Mary. Mary has the right answer because she understands it and John does not. Mary is more likely to convince John than Professor Mazur in front of the class, because she has only recently learned it. She still knows what the difficulties are that the beginning learner has. Whereas Professor Mazur has learned it such a long time ago, he can't even imagine the difficulties going on in John's mind. The better you know something, the more difficult it gets to teach because you're no longer aware of the conceptual difficulties of the beginning learner.
The mass broadcast expectation set in a classroom works against responsiveness. They don’t lend themselves to individually diagnosing each student, let alone customising each lecture accordingly.
But Eric had stumbled into a way to let students do this customisation for themselves. In small group conversations, they could assess each others’ mindsets and respond accordingly.
It actually took quite a while to find out that my award-winning lecturing was not really accomplishing what I wanted to accomplish. I was focusing information transfer, and hoping that sense-making would occur on its own, outside of the classroom.
Eric made his first steps in a new approach to university lectures that would spread around the country, what he'd soon call Peer Instruction.
I had my students read the book before coming to class. In class, I taught by questioning rather than by telling.
I'll ask a question. I'll give students time to think about it for a few minutes then commit to an answer. Then they try to convince each other of their answer and then I have them vote again, and we wrap up the cycle with an explanation. Basically, that cycle repeats until class time is up.
Twenty years after Eric Mazur's first developments with Peer Instruction, he reflects on his work in improving university education:
Education really is no longer about information. It's about how to use information.
If you design a bridge and the bridge is conceptually correct, but it collapses because it only withstands 1/10 of the weight it was supposed to withstand, you don't get any credit for that.
What is the process of education? Some people will say transmission of knowledge. But I can only transmit information. Knowledge is something
that needs to be constructed in the heads of the students.
Better understanding leads to better problem-solving but the converse of this statement is not true. Good problem-solving does not necessarily mean understanding.
The true hallmark of understanding is to be able to transfer your knowledge to a new context.
Eric Mazur shows us that success in education is defined by what the learner becomes. If their behaviour changes, only then has learning happened.
But to do that, educators need to step away from the instinct to teach more. That path leads to one-way information overload and away from the desired effect.
The true mark of success is when the learner evolves.