A/C Educator
The Lecture as a Learning Device
classes. The facial expressions on the stuThe challenge in dents made it obvious that they were captivated by his lecture. His lucid presentation, college teaching is notrange of knowledge, wit, humor, and enmanner made it difficult to turn covering the material, gaging one's attention awayfromthe speaker and It was no surprise to me that the stubut uncovering it (1). topic. dents broke into applause at the end of the I remember watching an episode of the U.S. TV science program Nova, which waa about Stephen Jay Gould, the noted paleontologist from Harvard University. What most caught my attention were clips of a lecture he was delivering to one of his Thomas J . Wenzel Bates College
class. I would have applauded too. I am sure that each one of us has experienced a presentation by a gifted lecturer and know what an enlightening and invigorating learning opportunity that can be. Of course, each one of us has also experienced the boring lecturer, when one's mind begins to drift and staying focused on the presentation becomes a chore. The lecture has been the mainstay of
college science teaching for a long time. The lecture is also the preferred mode of presentation at scientific meetings and in corporate settings. Lately, however, lecturing as a mode of teaching has come under increasing criticism with voices advocating that we adopt instead what is broadly termed collaborative learning. When people contrast the "sage on the stage" with the "guide on the side", it is apparent which phrase is pejorative and whiih is sot. Do these criticisms have merit? The effectiveness of lecturing as a learning device has been examined and it is worthwhile to consider the findings of these studies (1-15) Do students learn from lectures?
Typically, the lecture is a long period of
Analytical Chemistry News & Features, December 1, 1999 8 1 7 A
A/C Educator uninterrupted talk by the teacher. (In contrast to some disciplines, most science lectures involve considerable use of visual aids, either through the development of topics at the blackboard or with overhead transparencies.) In one study, lectures accounted for 92% of the class time in large science classes. The remaining 8% was about evenly divided between students talking and moments of silence (2). The material to be learned is usually presented in final form. Students mostly passive spectators in lectures There are certain drawbacks with lecturing. Even with visual aids, students require good auditory learning skills, a high working memory capacity, and good notetaking skills to benefit from a lecture. Students also need to be adequately prepared with the prior knowledge expected by the instructor (2). Although lecturing tends to promote the coverage and learning of factual material it has been shown to be no effective than reading at transmitting factual information to students provided suitable reading material exists (3) In the context of a lecture it is difficult to promote thinking and encourage students to analyze synthesize or integrate complex material Another drawback is that lecturing assumes that all students need the same information at the same pace without the benefit of much dialogue with the instructor. Unless students freely ask questions during a lecture, misconceptions or gaps in understanding are difficult to identify and correct. Some students even feel isolated in lectures, especially if they are confused or too timid to ask questions. Finally, after listening to an especially enthusiastic, engaging, and entertaining lecturer, students leave with the false impression that they understand the material only to realize later thcit it is more complex than imagined (I) A legitimate response to some of these drawbacks is that students must also bear considerable responsibility for their learning. The lecture notes, in combination with the textbook, provide the basis for continued study, refinement, and development of understanding. The disciplined student who reviews the material shortly after the lecture and before the next class will usu818 A
ally develop a deeper understanding than the student who leaves any substantive review until shortly before the exam. The ability to review assumes, however, that students leave the lecture with a thorough set of notes. Even the instructor who uses overhead transparencies and provides copies to the students adds a considerable amount of oral expository comments to the material (if the lecturer did not add information beyond the visual aids, then there would be no point in holding class).
Lecturing assumes that all students need the same information at the same time without the benefit of much dialogue with the instructor. But do students typically leave class with a thorough set of notes? To do so requires the students' complete attention on the material as it is presented. It has been found that the utility of a lecture is more dependent on how focused students are, rather than the ability of the lecturer to organize and develop the material (4). Many science lectures involve the development of a concept, perhaps with several pieces of evidence that tie together into a logical conclusion. Student attentiveness ir such a lecture is essential. One study examined students' thoughts and behaviors during lectures (4). The instructors in the study were willing participants in the process and were well regarded by students. The students' behaviors (e.g., note taking, fidgeting, sleeping, etc.) were recorded at specific intervals. Periodically, a bell was rung and the student participants were asked to record their thoughts immediately. The results of the study are illuminating. Students exhibited on-target, attentive
Analytical Chemistry News & Features, December 1, 1999
behavior 56% of the time and were observed fidgeting or exhibiting some other off-target behavior for the remainder. Students' self-reports showed them to be ontarget only 60% of the time. Off--arget thoughts recorded in the study showed how the lecture was competing with other significant aspects of the students' lives. Common categories of off-target thoughts included issues of time (e.g., how long until class ends, an obligation occurring later in the day), personal relationships food and thoughts about other people in the class which often included musings about the instructor The general patterns and extent of on- and off-target behavior and thoughts did not vary bv gender The results were also fiuite comnarable from instructor to
instructor and from class to clace
Other studies have found that student attention decreases as the lecture proceeds (5-7). After a "settling in" period of about five minutes, students did well assimilating material for five minutes, after which confusion or boredom reduced attentiveness. An analysis of student notes showed that about 40% of the content was recorded in a 15min lecture, 25% in a 30-min lecture, and 20% in a 45-min lecture (5)) There was usually some revival of interest toward the end of the class. The consistent finding of these studies on lecturing is that no ordinary student is able to track the relevant content for an entire 50-min lecture It is unreasonable, though, to think that the lecture as a mode of teaching could or should ever be entirely eliminated. Certain portions of analytical chemistry courses involve dissemination of factual information (e.g., components and operation of an instrument), and this material is often appropriately taught through lecturing (1). Even in a course that makes extensive use of collaborative learning, the instructor must at times summarize findings, relate outcomes of class exercises to an accepted body of knowledge, and explain current work that might not be in the textbook. Given that lecturing will always be some component of teaching are there strategies to improve the quality of the learning that occurs? Lectures that work
Because it is the rare student who can follow an entire lecture, redundancy is usually
necessary. As some would advocate, 'Tell them what you are going to tell them, tell them, and then tell them what you told them (1)." Questions must be encouraged, and outside readings that provide a clear and thorough explanation of the material are important. Skillful lecturers maintain eye contact, avoid distracting behaviors, modulate voice pitch and volume, and use appropriate gestures and movements (8). Achievement by students is generally higher when presentations are delivered with enthusiasm (9) One strategy that can enhance the quality of learning that occurs in lectures is the use of pauses (10-13). Many instructors pose questions to the students during the lecture, but then do not give them enough time to think about the question and formulate a response. Typically, instructors wait no more than one second after posing a question before answering the question, repeating the question, redirecting the question to another student or starting a new sequence of questions (12) If the goal is to actually have students consider the question sufficient time for formulating a rf^^normf m nfif*fissaT*v Inf*nmoT"3ting planned pauses into the lecture can be especially valuable During these pauses students can review their notes and discuss their iinrfpnitanrlino" rvf the material with a n e i t r h h n r TTiere micrht tVifti K P a n n p c t i n n
and answer
to further Harify
The utility of planned, 2- to 3-min pauses interspersed at intervals of between 12-18 min of lecturing has been evaluated (13). During the pauses, students worked in pairs to review the material with no interaction with the instructor. Another class, which served as the control, received the same lecture with the same visual aids and anecdotes. At the end of the lectures in both types of classes students were asked to write everything they could remember (free recall) A test was given 12 days after the last lecture In two separate courses over two semesters students in the classes with the pauses did significantly better on both the free recall and test (mean scores were nn to two letter grades better dependinD" on trie rntrtff nnints"! The chanrp to immediately and actively m a t e r i a l a n r l +Vi£» b r e a l / - frr»m r\r\te
talrinrr
enabled the students to begin the next portion of the lecture with renewed interest and attentiveness. Incorporating such pauses into the lecture involves little effort on the part of the instructor and only sacrifices about six min of lecture time. If the goal of teaching is to uncover material for the students and not just to cover it, alternatives or modifications to the lecture as it is typically practiced in college courses today are warranted. References (1) Johnson, D. W.; Johnson, R. T.; Smith, K. A. Cooperattve Learning: :ncreasing College Faculty Instructtonal Productivity; ASHE-ERIC Higher Education Report No. 4; The George Washington University, Graduate School of Education and Human Development: Washington, DC, 1991. (2) Bonwell, C. C; Eison, J. A. Active Learning: Creating Excitement in the Classroom; ASHE-ERIC Higher Education Report No. 1; The George Washington University, Graduate School of Education and Human Development: Washington, DC, 1991. (3) Bligh, D. A What's the Use ofLecturess Penguin: Harmondsworth, U.K., 1972. (4) Pollio, H. What Students Think About and Do in College Lecture Classes. In Teaching-Learning Issues; University of Tennessee, Learning Research Center: Knoxville, TN, 1984; pp 3-18. (5) Penner, J. G. Why Many College Teachers Cannot Lecture: How To Avoid Communication Breakdown in the Classroom. Charles C. Thomas: Springfield, IL, 1984. (6) Stuart, J.; Rutherford, R. J. D. Lancet 1978.2, 514-16. (7) Verner, C; Dickinson, G. Adult Education 1967,17, 85-100. (8) Rosenshine, B. Educational Leadership 1968,26, 303-09. (9) Armento, B.J. Teacher Education 1977, 28, 46-52. (10) Rowe, M. B.J. Res. Sci. Teaching 1974, 11, 81-94. (11) Rowe, M. B. Teaching the Sciences. In New Directions for Community Colleges; Brawer, F. B., Ed.; Jossey-Bass: San Francisco, CA, 1980; No. 31. (12) Rowe, M. B. Teaching Science as Conttnuous Inquiry; McGraw-Hill: New York, NY, 1973. (13) Ruhl, K. L.; Hughes, C. A; Schloss, P. J. Teacher Education and Special Education 1987,10,14-18. (14) Costin, F. British J. ofEducational Tech. 1972.3, 4-30. (15) McKeachie, W.; Kulik, J. Review of Research in Education; Kerlinger, F., Ed.; Peacock: Itasca, IL, 1975.
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COMING JANUARY 2000
Wenzel is a professor of chemistry at Bates College. Address correspondence to Wenzel, Dept. of Chemistry, Bates College, Lewiston, ME 04240 (
[email protected]). Analytical Chemistry News & Features, December 1, 1999 8 1 9 A
