Discussions of education are generally
predicated on the assumption that we know
what education is. I hope to convince you
otherwise by recounting some of my own
experiences. When I started teaching
introductory physics to undergraduates at
Harvard University, I never asked myself how
I would educate my students. I did what my
teachers had done--I lectured. I thought
that was how one learns. Look around
anywhere in the world and you'll find
lecture halls filled with students and, at
the front, an instructor. This approach to
education has not changed since before the
Renaissance and the birth of scientific
inquiry. Early in my career I received the
first hints that something was wrong with
teaching in this manner, but I had ignored
it. Sometimes it's hard to face reality.
When I started teaching, I prepared lecture
notes and then taught from them. Because my
lectures deviated from the textbook, I
provided students with copies of these
lecture notes. The infuriating result was
that on my end-of-semester
evaluations--which were quite good
otherwise--a number of students complained
that I was "lecturing straight from (his)
lecture notes." What was I supposed to do?
Develop a set of lecture notes different
from the ones I handed out? I decided to
ignore the students' complaints.
A few years later, I
discovered that the students were right. My
lecturing was ineffective, despite the high
evaluations. Early on in the physics
curriculum--in week 2 of a typical
introductory physics course--the Laws of
Newton are presented. Every student in such
a course can recite Newton's third law of
motion, which states that the force of
object A on object B in an interaction
between two objects is equal in magnitude to
the force of B on A--it sometimes is known
as "action is reaction." One day, when the
course had progressed to more complicated
material, I decided to test my students'
understanding of this concept not by doing
traditional problems, but by asking them a
set of basic conceptual questions (1,2).
One of the questions, for example, requires
students to compare the forces that a heavy
truck and a light car exert on one another
when they collide. I expected that the
students would have no trouble tackling such
questions, but much to my surprise, hardly a
minute after the test began, one student
asked, "How should I answer these questions?
According to what you taught me or according
to the way I usually think about these
things?" To my dismay, students had great
difficulty with the conceptual questions.
That was when it began to dawn on me that
something was amiss.
In
hindsight, the reason for my students' poor
performance is simple. The traditional
approach to teaching reduces education to a
transfer of information. Before the
industrial revolution, when books were not
yet mass commodities, the lecture method was
the only way to transfer information from
one generation to the next. However,
education is so much more than just
information transfer, especially in science.
New information needs to be connected to
preexisting knowledge in the student's mind.
Students need to develop models to see how
science works. Instead, my students were
relying on rote memorization. Reflecting on
my own education, I believe that I also
often relied on rote memorization.
Information transmitted in lectures stayed
in my brain until I had to draw upon it for
an exam. I once heard somebody describe the
lecture method as a process whereby the
lecture notes of the instructor get
transferred to the notebooks of the students
without passing through the brains of either
(3).
That is essentially what is happening in
classrooms around the globe.
Since this agonizing discovery, I have begun
to turn this traditional
information-transfer model of education
upside down. The responsibility for
gathering information now rests squarely on
the shoulders of the students. They must
read material before coming to class, so
that class time can be devoted to
discussions, peer interactions, and time to
assimilate and think (4).
Instead of teaching by telling, I am
teaching by questioning.
I
now structure my time during class around
short, conceptual multiple-choice questions.
I alternate brief presentations with these
questions, shifting the focus between
instructor and students. The questions
address student difficulties in grasping a
particular topic and promote thinking about
challenging concepts. After posing the
question, I give the students 1 to 2 minutes
to think, after which each must commit to an
individual answer. They do this by
submitting their answers using handheld
devices called "clickers" (see the figure).
Because of the popularity of these devices,
questions posed this way are now often
referred to as "clicker questions." The
devices transmit the answers to my computer,
which displays the distribution of answers.
If between 35% and 70% of the students
answer the question correctly, I ask them to
discuss their answers and encourage them to
find someone in the class with a different
answer. Together with teaching assistants, I
circulate among the students to promote
productive discussions and guide their
thinking. After several minutes of peer
discussion, I ask them to answer the same
question again. I then explain the correct
answer and, depending on the student
answers, may pose another related question
or move on to a different topic. This
approach has two benefits: It continuously
actively engages the minds of the students,
and it provides frequent and continuous
feedback (to both the students and the
instructor) about the level of understanding
of the subject being discussed.
I
often meet people who tell me they have
implemented this "clicker method" in their
classes, viewing my approach as simply a
technological innovation. However, it is not
the technology but the pedagogy that matters
(5).
Unfortunately, the majority of uses of
technology in education consist of nothing
more than a new implementation of old
approaches, and therefore technology is not
the magic bullet it is often presumed to be.
Although clickers offer convenience and (at
least for now) an amount of trendiness that
appeals to students, the method can be
implemented with flash cards, which are
inexpensive and never prone to technological
glitches (6).
Data obtained in my class and in classes of
colleagues worldwide, in a wide range of
academic settings and a wide range of
disciplines, show that learning gains nearly
triple with an approach that focuses on the
student and on interactive learning (7,8).
Students are given the opportunity to
resolve misunderstandings about concepts and
work together to learn new ideas and skills
in a discipline. Most important, students
not only perform better on a variety of
conceptual assessments, but also improve
their traditional problem-solving skills (9).
Also, data show that such interactive
engagement helps to reduce the gender gap
that exists in introductory physics
classrooms (10).
So, evidence is mounting that readjusting
the focus of education from information
transfer to helping students assimilate
material is paying off. My only regret is
that I love to lecture.
References and Notes
D. Hestenes, M. Wells, G.
Swackhamer,Phys.
Teach.30,
141 (1992).
A version of (1)
revised in 1995 by I. Halloun, R. Hake,
E. Mosca, and D. Hestenes is available
in (4).
D. Huff,How
to Lie with Statistics(Norton,
New York, 1954).
E. Mazur,Peer
Instruction: A User's Manual(Prentice
Hall, Upper Saddle River, NJ, 1997).