• Issue 61 / January - February 2008

    Peer Instruction: A Better Way to Learn

    Ertan Salik

    Teaching and learning are two common human activities. If we need to name a great difference between humans and animals, this is the one. As Nursi points out1 almost from the very moment of birth an animal seems to have been trained and perfected elsewhere, whereas people are born knowing nothing of life and their environment and so must learn everything. Learning more and the correct things improves one’s life. So, we are all concerned with how we can learn more efficiently, and, in turn, how we can teach more efficiently.

    Education becomes more formal at school. There are a great many different teaching styles inspired by different educational philosophies. Likewise, there are very many learning styles based on different personalities. Every person is created differently and every person may have a slightly different learning style. However, at schools where mass teaching is done, teachers need to decide on a certain method. There are some traditional methods and some novel ones. Here we will focus on peer instruction,2 a non-traditional teaching method developed over the last decade based on physics education research, and later applied in other science teaching as well. We will also try to extract lessons from the peer instruction experience to guide us not only in learning in the classroom but also in everyday informal learning practices.

    Eric Mazur is a professor of physics at Harvard University. About a decade ago, Mazur discovered that his students could not correctly answer seemingly simple qualitative questions, despite being able to work through much more difficult quantitative problems. He was shocked as he was considered to be one of the best instructors in the physics department. Mazur began to document the disparity between student performance on the two types of questions, by including on his exams paired qualitative and quantitative questions on a single physical concept. He soon confirmed that for his students, success in solving traditional physics problems did not imply that they understood the underlying physics. Many physics instructors across the United States shared Professor Mazur’s experience. Mazur started developing what is now known as peer instruction.

    As the name suggests, peer instruction promotes learning through interaction with one’s peers in the classroom, in addition to listening to the instructor. This is very new, considering that many remember science classes in the form of a plain lecture, where the only player is the instructor, and the students are the audience, except for a few outgoing students who are not always appreciated by their peers. Peer instruction transforms the students into active players during the class. This is actually common sense in all our education experiences. If you just listen to an idea, you will understand very little, and retain very little. If you think about the subject matter, try to apply it in different circumstances, and finally teach it to someone else then your chance of comprehension and retention greatly improves. This is what the instructor achieves through peer instruction. The students are gently pushed toward thinking, discussing, and finally teaching each other, and so they learn more and better.

    Every class in peer instruction includes three or four short mini-lectures followed by (or sometimes preceded by) a conceptual question. Students are assigned prior reading so as to come to the class prepared and to have at least some familiarity with the new concepts and terminology. Each mini-lecture’s goal is to highlight certain concepts and give the students further insight. Very different from traditional physics lectures, the instructor does not feel obligated to solve many example problems where a lot of math is needed. That is done through homework and during the problem sessions, which are usually administered by teaching assistants. Between mini-lectures three to five conceptual questions are distributed. Each conceptual question is a qualitative multiple-choice question that gives students and the instructor a means to assess what students have learned. Most questions are asked twice. In the first stage, the instructor shows the question on a projector screen and reads it aloud. Each student is asked to think individually about the answer. No talking is allowed. At the end of this first one- or two-minute period, the instructor asks the students to show their responses. This can be done with flashcards, or electronic transmitters (clickers). A flashcard may have the choices (A, B, C, …), or the instructor may prefer to use color flashcards. Some schools provide students with clickers (or students buy them), and the instructor has the receiver that is connected to a computer.

    After receiving the answers from the students, the instructor assesses the situation. If there are only a few correct answers, then the question was asked prematurely. If there are only a few incorrect answers, then the question was too easy, no more time is devoted to that concept. However, in most cases the instructor selects a question to which 30–70% of the answers will be correct. Then, in the second stage, without giving the correct answer, the instructor asks the students to turn to their peers sitting next to them, and discuss the answer and its reasoning. This is peer instruction. These interactions between students have proven very useful. At the end of the second stage, which typically lasts two to three minutes, the instructor asks the students to show their responses to the same question once again. It has been shown that most of the time the number of correct answers goes up. Clearly, success is conditional on the pre-class reading, a mini-lecture that highlights the concepts, and selection of the carefully designed conceptual questions. Based on the responses, the instructor can decide whether to elaborate on the topic or proceed to something new.

    Here is a conceptual question3 that may be asked while studying the law of gravitation:

    The Moon does not fall to Earth because…
    1. it is in the Earth’s gravitational field.
    2. the net force on it is zero.
    3. it is beyond the main pull of the Earth’s gravity.
    4. it is being pulled by the Sun and planets as well as by the Earth.
    5. All of the above.
    6. None of the above.

    At this point we suggest that the reader should think about this question before reading the next paragraph, which includes the correct answer at the end. If possible, ask someone near you and discuss your reasoning.

    This question is carefully designed with choices representing various misconceptions. For example, any student with some introductory knowledge of physics will accept that if the net force on an object is zero, then the object will not move, so it is tempting for some students to say, “Oh, yes. The Moon does not fall to Earth. This means that the net force on it is zero!” Or, everybody has a direct experience of the gravitational pull of the Earth. You jump and you fall to Earth. You cannot escape. Again, it is tempting to say that the Moon is beyond the main pull of the Earth’s gravity, but that is not true because if there were not enough gravitational force on the Moon, it would escape the Earth’s orbit. Option 4, for example, is correct as a statement. By virtue of having a mass, the moon is pulled by the Sun and other planets. One might tend to think that there is a balance between the gravitational forces applied by the Earth and other heavenly objects. But, no, that is not the actual reason for the Moon not to fall to Earth. None of the options alone gives the correct answer. Since two of the options (2 and 3) are incorrect, the correct answer to this question is option 6, “None of the above.” The correct answer is that the Moon orbits the Earth as well as being pulled by its gravitational force. The reason the Moon keeps changing its direction is the gravitational pull of the Earth. The Moon was given an initial speed so that it does not fall. If the Moon should stop at any instant, it would fall to Earth.

    To reiterate our main point, peer instruction causes students to think through and apply a general principle to different cases through conceptual questions and teach each other what they have just learned. That is, our brain becomes much more active, and it is forced to synthesize difference pieces of information, rather than keeping busy with factual information only.
    Research has shown that peer instruction improves the learning gains of the students greatly.4,5,6,7 Peer instruction has been used in astronomy, chemistry, biology, and mathematics as well. How can we benefit from the peer instruction experience to improve our everyday teaching and learning practices? Before trying to answer this question, let us remember occasions when we learn and teach in our daily lives. We teach and learn when we talk to our friends. When we browse through a newspaper, listen to the radio, or watch a TV program, we are bombarded with information. We read books hoping to learn something from them.

    The first message we should receive from the success of peer instruction is that passive listening and watching only injects a lot of information in a short time into our memories. Because such information is not processed with an active mind, or we do not try to apply it in different situations, we should be aware that such information might not be so reliable in general. The irony is that many people in the twenty-first century look to the TV, movies, and radios for information. On the TV screen we see twenty-four pictures every second, that is, about a quarter million pictures daily, if we watch TV for three hours per day. In order for TV and radio to be useful, as peer instruction shows, viewers and listeners need to stop and think about what they have just seen and listened to. If possible, then turn to a friend, discuss what you have just watched and get their opinion. Try to teach what you have just learned and see the reaction of people around you.

    When we read we have more time to think. We should gently push our brains to make connections with what we know, and what we have just read. What is the purpose? What is the message? Why is this significant? Then again, try to teach it to a friend, enter into a short discussion. This can really help minimize misconceptions and refine our understanding. It will help us assimilate the information, and make it our own. As Nursi puts it, “A learned guide should be a sheep not a bird. A sheep gives its lamb milk, while a bird gives its chick regurgitated food.”8 Yes, we should try to digest information, and our chances of digesting it improves with continuous thought, meaningful discussions, and when we try to teach someone else, just like what happens in peer instruction.

    1.Bediuzzaman Said Nursi, The Words, The Twenty-Third Word, Fourth point, NJ, The Light: 2005, pp 331–32.
    3.Eric Mazur, Peer Instruction: A User’s Manual. Prentice-Hall, Upper Saddle River, NJ, 1997.
    4.D. Meltzer, and K. Manivannan, Am. J. Phys. 70, June 2002.
    5.Mark C. James, Am. J. Phys. 74, August 2006.
    6.Catherine H. Crouch and Eric Mazur, Am. J. Phys. 69, September 2001.
    7.T. J. Bensky, Am. J. Phys. 71, November 2003.
    8.Bediuzzaman Said Nursi, The Letters, Seeds of Truths, NJ, The Light: 2007, pp 445-458.


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