The Good Lecture…
G. K. Gilbert was arguably the best geologist America has produced. He received a classical education rich in languages and math and physics but poorer in other sciences. Much later, in advocating a particular style of intellectual attack suitable for geology, he reflected on college courses. “Gilbert [said] in an address, 20 years [after he graduated], that the important thing is to train scientists rather than to teach science, and that the ‘practical questions for the teacher are, whether it is possible by training to improve the guessing faculty, and if so, how it is to be done;’ thus implying not so much that, in his own experience, accurate observation is easy, but that successful guessing is difficult. It must also have been not his professor’s idea but Gilbert’s, prompted perhaps by a remembrance of an over-insistence on the names of things, that the content of a subject is often presented so abundantly in college teaching as to obstruct the communication of its essence, and that the teacher ‘might do better to contract the phenomenal and to enlarge the logical side of his subject, so as to dwell on the philosophy of the science rather than on its material.'” (Wm. Morris Davis, National Academy Memoir on Gilbert, 1928).
This comes up in part because of a recent New York Times op-ed in favor of lecturing that rather unfortunately seems to pit student-centered learning as practiced in the sciences against lecture-based learning in the humanities. Molly Worthen, in this column, argues that “Lectures are essential for teaching the humanities’ most basic skills: comprehension and reasoning, skills whose value extends beyond the classroom to the essential demands of working life and citizenship.” One has to wonder, are these skills limited to the humanities? Shouldn’t scientists also be learning how to comprehend and reason thoroughly?
At first blush, newer styles of teaching with in-class exercises and the like would seem to be what Gilbert was looking for, but on closer examination, it isn’t clear that this is really enlarging the logical side of the subject.
This gets to the very heart of the “guide on the side” mode of teaching. It is very good at getting basic relationships through and can work well at times in getting students to recognize how to apply some of these relationships in new situations. There are several studies showing quantitative gains in what the instructors think they are teaching. But get to the point of a much higher hill to climb and the gains maybe aren’t there. The kinds of exams and surveys used in the evaluation of teaching in the sciences do not demand the student develop or defend some line of logic. In a class like historical geology, where we might be asking students to connect changes in the fossil record with changes in climate with changes in tectonics, we often find tremendous difficulties and frustration. That higher level of understanding that can integrate material and synthesize it is extremely difficult to tease out. It does not seem to be a desired outcome of the science education projects out there. This isn’t to say that the changes in science courses are not an improvement (the fewer days of instructors spewing terms like regolith and trondhjemite at hapless students, the better), merely that the defense of the lecture suggests that there are aspects of an education that are missing.
This defense does help to point out what is bad in science lectures. Pouring forth a wealth of facts without a context or argument or some other excuse leads nowhere. And yet science lectures often devolve to exactly this. Perhaps the challenge isn’t as much to eliminate science lectures as to reexamine their purpose. If all you are doing is showing, say, how radiometric dating works, then in-class exercises might be fine. If you are looking to argue for the relevance of radiometric dating versus, say, Biblical dating of events then maybe something different is appropriate. Maybe it isn’t nearly as much about how we teach as what we teach….