Wednesday, May 30, 2012

Peer Instruction Beats out Lecturing by Factor of Two

In the early 1990s, Harvard physics professor, Eric Mazur, was teaching advanced physics courses to bright students. He gave exciting lectures, complete with compelling, thought-provoking demonstrations.  He was praised by students for his clarity in delivering the material.  Then, something unusual happened.

Mazur set out to gauge the effectiveness of his teaching scientifically.  He employed a standardized test known as the Force Concept Inventory (FCI) to assess his students' conceptual understanding of mechanics, before and after teaching his courses.  The results surprised him.

He was not surprised that most students entering his class came in with a relatively weak understanding of mechanics.  He was, however, astounded that after having taken his mechanics course, his students performed only marginally better on the FCI.  Mazur was dumbfounded.  In the years that followed, he set out to determine, scientifically, what constitutes effective pedagogy for science education.

Traditional lectures, where a teacher communicates information to students who dutifully take note of the content, are fairly useless.  At its best, such an approach can be entertaining, but not cognitively stimulating for students.  In fact, cognitive function in students while attending a lecture (even a good one) has been shown to be lower than while sleeping.  In this context, who can fault a student for sleeping through a lecture?

Students learn content in a much deeper sense when they are actively engaged.  Rather than the passive recording of information, Mazur had his students use an in-class technique known as peer instruction.  Here, the students enter class with some background information on the content because they did some assigned readings and practice questions to prepare for the lecture.  When trickier problems are posed during class, the students attempt to solve them in groups of three or four.  The process involves students defending their own solutions and reflecting on what their fellow students think.

This non-standard approach to teaching is actually quite sensible.  There are two parts to learning... The first, the transfer of information, is the easy part.  The second, the making sense of the information, is the hard part.  Why should in-class time be spent regurgitating content that is readily available in a textbook?  This is the easy part, and can be done to a reasonable extent individually by each student.  Classroom time should be used to understand this information.  Historically, this more difficult aspect of learning has been done by students on their own time, in the form of homework.  The idea with peer instruction is that the teacher is present to manage the harder more critical part of learning.

What is more, a discourse occurs between the majority of the class, not just a few extroverted students who choose to partake in a typical classroom discussion.  Also, students are communicating with students.  When information comes from a teacher, students see this person as an authoritative figure - an expert.  Since the expert is probably correct, students turn their thinking caps off, as there is no need to question the correctness of the expert.  On the other hand, a fellow student may very well be wrong, and so students tend to be critical of their approach.  This transforms the student from passive observer to active participant.

If you would like to see this process in more detail, you can watch Professor Mazur describe it himself in his presentation: "Confessions of a Converted Lecturer".

I had the pleasure of witnessing Eric Mazur present his latest pedagogical research live at Dawson College last week (yes, there is some irony in conveying the shortcomings of lecturing through a lecture).  In his talk, he reminded the audience of his breadth of research indicating that the improvement on the FCI for students taught using active learning techniques rather than traditional lecturing was about two times greater.

He went on to discuss that while everyone benefits from active learning, females seem to benefit most.  The reasons for this are only speculative at this point.  He then described the futility of science demonstrations conducted by teachers as students simply observe.  If the students are not called on to make a prediction before the demo and/or to properly reflect on it, then it is more likely to confuse students than to reinforce course material.

Perhaps his most interesting finding is the one he concluded with.  Mazur showed that students who stated that a given science topic was clear to them and had no questions or concerns regarding it, were two times more likely to not understand it as students who did have questions.  The moral here is that confusion is not a bad thing - rather, it is the first step to learning something.

I want to remind the reader that all of the conclusions presented here are supported by data.  This is the story of a scientist who used a scientific method to identify effective teaching practices.  Science teachers wish to instill in their students a profound respect for the scientific method; it is time that we practice what we preach, and adapt our teaching methods according to the scientific evidence.

It makes sense that there be some resistance to make such a major change to the way science courses run.  There is resistance on the student end as well as the teacher end.  My students last semester said they needed to hear it from me, that they needed me to walk them through it, and that they were not disciplined enough to learn on their own time.  Well, this tells me that these students need to develop more discipline, but also that the textbook might be overly complex for their level of physics and math knowledge.

As for the teachers, we are just doing what was done for us in our school years.  We enjoyed going to school and attending lectures.  Furthermore, we enjoy giving lectures; they are so engaging... for us.  Part of the problem here is that the science students who go on to become science teachers are not representative of the science student population.  They tend to be individuals for whom science seemed, for the most part, quite intuitive.

I cannot speak for any other teachers, but I do intend to change my teaching approach over the coming year.  I have recognized for a long time that one learns content most effectively by teaching.  By employing peer instruction in my class, I will begin to offer my students that opportunity.

1 comment:

Brett Moller said...

Agree - we are finding that to be true even with younger students... this is some work done by a 12 year old student to help teach peers a common spelling rule...