Saturday, February 14, 2009

Hey, college science teachers! Time to Play Baseball!

The distinguished scientist Bruce Alberts, formerly President of the National Academies of Science, is now Editor-in-Chief of Science, one of the top voices for science both within and outside the science community. He has a bully pulpit, and he’s using it these days to beat the drums for reform in science education. He led off the year 2009 with an editorial entitled “Making a Science of Education”. He argues there that we need to use all the new tools placed at our disposal by technological advances to deliver science education to young people in both school and non-school settings. But as Alberts has made clear on other occasions, improving science education will depend on much more than implementing new technologies. As he says, in addition to emphasizing a knowledge of the facts and figures of a given science, or rote knowledge of how to use formulas and diagrams, three additional goals “of equal merit and importance are to prepare students to generate and evaluate scientific evidence and explanations, to understand the nature and development of scientific knowledge, and to participate productively in scientific practices and discourse.” These goals must be addressed if we are to have a scientifically literate citizenry, and if we are to inspire young people to consider careers in science. But he goes on to ask of science courses taught at the college level: “Why do most science professors teach only the first one [of these four goals]?”

It’s not as though there were no evidence bearing on this subject. For starters, consider the format of learning. It has been known from several studies that the amount of conceptual understanding conveyed in a typical science lecture is pitifully small. Eric Mazur, professor of physics at Harvard University, has been teaching introductory physics to undergraduates for many years. In a recent Perspective on Education in Science Mazur describes how he came to realize that while lecturing is a great ego trip for him, as it is for all “popular” science lecturers, he was conveying very little conceptual understanding to his students by that mode of delivery. He describes the techniques he now uses to impart greater conceptual understanding of physics. They involve dynamically engaging the students during class in active discussions of the concepts needed to come up with a correct answer to a question. The students come to class now to do real intellectual work!

His methods have been adapted by others; there is a great paper in that same issue of Science on how in-class peer discussion improves student performance on measures of conceptual understanding in biology as well as physics. These successes are readily understandable in terms of cognitive science principles. Frederick Reif, in his new book, “Applying Cognitive Science to Education”, shows that the standard lecture format does not get at students’ conceptual misunderstandings. They memorize a lot of stuff they are told they should know, but the process does nothing to help them overcome their limited and often incorrect beliefs of how things work in the world. Reif shows that to overcome this sort of blockage to understanding, students must be presented with questions and problems that stimulate them to rethink their beliefs, that produce a reorganization in their conceptual frameworks. Reif writes about teaching mathematics and physics, but what he, Mazur and others have to say applies as well to chemistry, biology or any other introductory science course. (Reif’s book is reviewed in Science)

Given that the methods employed in teaching introductory science courses fail to convey genuine understanding of the subjects, one has to wonder why science departments and faculty persist for the most part with the traditional format. Sure, we now have Powerpoint presentations and visual aids to enliven lectures, but the underlying metaphor that sustains this mode of instruction remains the same. It was powerfully analyzed many years ago by Michael J. Reddy, in his classic chapter in the book “Metaphor and Thought”. I can’t do justice in this short space to Reddy’s analysis of the underlying concepts we hold of how we communicate, but a much bowdlerized version is as follows:
Ideas are (metaphorically) objects. Our minds are (metaphorically) containers that hold these objects. Communication consists in putting these thoughts or ideas into other containers -words, sentences or paragraphs. We communicate by placing our thoughts and ideas into these containers- words, sentences, paragraphs, and so on-that are then sent from one person to another through some sort of conveyance-direct talk, TV, telephone, writing. The recipient, takes them out of the conveyance and places them in his/her mind. If you are not into conceptual metaphor theory this will sound weird, but believe me, it is a powerful and useful way to understand what people believe, mostly unconsciously, about how they communicate. The wonderful book by George Lakoff and Mark Johnson, “Metaphors We Live By” contains a discussion of Reddy’s conduit metaphor, in which they show that this metaphor underlies much of our understanding of human communication. One consequence of the conduit metaphor is that we think of communication as a passage of an “object” from speaker to listener, and that this process occurs without any change in the object. Whatever it was to the speaker, it is to the recipient. In Reddy’s words, we “transfer human thoughts and feelings.” So in lecturing we imagine that we are transferring ideas from ourselves to the students, and they absorb these ideas in the form and shape that we gave to them as we uttered them. But as Reddy. Lakoff and Johnson make clear, that’s all wrong! We know full well from a multitude of psychological and cognitive studies that it doesn’t work that way. What a thought means to the speaker may not match at all what that thought means to the recipient. Thus, the lecture format, in which the intended meaning of the lecturer’s words is mostly not conveyed, is a poor means of transferring ideas, and particularly conceptual understanding.

So why do science educators at the college level keep to this failed method of education, especially in the context of the large lecture hall? There are several reasons, some not so flattering to the professoriate:
· Ignorance. Not many teaching faculty in the sciences pay much attention to the literature of science education, nor are they aware of cognitive science results that might inform their decisions on how to teach more effectively.
· Inertia and stubbornness. It has always been done it this way, and it seems to be satisfactory. Clearly, in this response there is a lot of denial, laziness and hubris. The problems are with the students, not with us.
· Lack of commitment. It would take too much effort to change to another system. To busy faculty, whose teaching duties often take second place to their research ambitions, the effort needed to research best practices, prepare an entirely new set of materials for conducting the class, and implement new technologies such as the “clicker” responders that Mazur and others use seems overwhelming. It is easy to just keep at the same old way of doing things.
· Lack of support from departments and colleges. Many faculty who might be willing to make an effort to instigate change are not encouraged by the administrations of their departments and colleges.
· Assessment. It is difficult to properly assess a student’s conceptual understanding of material, especially when one is dealing with large classes. Try writing a multiple choice test that really gets at whether students have a conceptual understanding of the material. It is much easier to test for whether students can “name that compound” or “plug and chug.” Much has been written about all the grievous failings of programs that call for assessments based on test scores. But even after taking account of the ways in which such standards are gamed- for example by teaching to the test – the simple fact is that there are no really good instruments for evaluating conceptual understanding that can be conveniently applied to large groups of students. Ever try grading an essay question administered to 1,200 students?

This list is hardly exhaustive, but it does illustrate the impediments to real change. But as Alberts has written, if the model set by the colleges doesn’t change, it is doubly difficult to instigate change at the K-12 level. So we need to keep working at this, at every level.
As a coauthor of a widely used general chemistry textbook, I feel obliged to say that the problem is not with the textbooks available, or at least not with the ones I am familiar with. Good textbooks do of course provide loads of factual information, nomenclature and so on, but they also encourage conceptual understanding and application of science to the real world. These texts are precisely what a teacher needs to build a format based on problem-solving and conceptual reasoning.

My previous blog had to do with baseball and science. I hope to come back to that analogy in further discussion of science education. For now, just imagine you are a little league coach with a new bunch of kids who don’t know a lot about baseball. Imagine teaching them baseball as if you were a college level chemistry lecturer. Would that work? Or conversely, imagine that you are responsible for teaching some kids about chemistry. Imagine teaching them chemistry as if you were a little league baseball coach. The one mode is “learn by listening”. The other is “learn by doing.”

1 comment:

  1. I agree with what has been said. Although a lecturer may formulate a basic scientific concept in a clear and linguistically understandable oral expression, the student too often may understand the semantic meaning of the sentence without grasping the concept, which requires adequate mental preparation and thought.
    I would ask a question: do those small collges noted for their science teaching actually achieve a more efficient transmission of underlying scientific concepts (by any objective measure), and do they employ markedly different teaching methods?