Issue 34, Spring 2008

William A. McEachern, Editor

Teaching, Thinking, and Learning

The Cognitive Science Society holds its 30th anniversary conference this July. The group's objective has been no less than developing a "unified theory of cognition." At the first conference, Herbert Simon, fresh off his Nobel Prize in economics, sounded this keynote: "Cognitive science is, of course, not really a new discipline, but a recognition of a fundamental set of common concerns shared by the disciplines of psychology, computer science, linguistics, economics, epistemology, and the social sciences generally. All of these disciplines are concerned with information processing systems, and all of them are concerned with systems that are adaptive..."(Simon, p. 33). Though cognitive science remains a work in progress, with most areas far from settled, decades of experiments have yielded enough fruit to warrant review in this issue of The Teaching Economist.

The fundamental goal of education is generating learning that is durable, flexible, and transferable in a generalized way to new situations. Cognitive scientists have drawn three conclusions about learning that have special relevance for teaching: (1) people have separate information processing channels for visual-spatial material and for verbal material; (2) people can pay attention to only a few pieces of information in each channel at a time; (3) people learn by focusing on the relevant material, organizing it into a coherent mental structure, integrating it with their prior knowledge, then retrieving that new knowledge. All this seems straightforward enough, but dozens of laboratory experiments suggest that instructors and students alike are easily misled about what works and what doesn't. For example, measures that boost short-term learning may not work in the long term, while measures that introduce difficulties for learners in the short term seem to aid long-term learning and transfer. Here are some findings (references are listed on the back page under "Odds and Ends").

• Intuition misleads students about how they learn.
  How many times have you heard this lament from a student who just did poorly on an exam: "But I read each chapter twice!" Students mistakenly believe they function like memory machines. They sit in class and soak up the knowledge. They read a chapter and absorb the material; read it again and encode it. All this sounds reasonable, but cognitive scientists find no evidence to support this memory-machine model as an efficient way to learn. Instead, new information enters long-term memory only if linked to what the student already knows. This linking, or mapping, is then reinforced by retrieval.


• The single most important student activity in promoting long-term learning is practicing retrieval.
  As noted already, students learn by organizing new information into a coherent mental structure, integrating that new material with their prior knowledge, then retrieving that information from memory. Students practice retrieval by generating responses based on minimal "cues," repeated over time. Experiments by Cull and many others find that learning improves when students actively retrieve information from memory rather than passively studying course material. Practicing recall, by engaging the learner, is far superior to rereading class notes or textbooks. Information that's more frequently retrieved thereby becomes more retrievable in the future and is therefore more transferable to other situations. By recalling information repeatedly, especially in varied contexts, the student strengthens access to that information across contexts. Students practice recall during study sessions and during tests. Retrieving is more effective the less the student relies on external memory cues.


• Instructors can help students practice retrieval.
  Ideas imbed in long-term memory when students have opportunities to retrieve, review, and reflect on them. To engage the course material actively, students need to develop cues that trigger links. Give students time during lectures to review and apply ideas. Stop to ask questions that help students relate lecture material to what they already know. Use prompts that encourage students to pose and answer deeper questions of course material. And give assignments that encourage them to retrieve key information. You might, for example, ask students to create a matrix, flow chart, table, or map based on course material. And encourage students to form study groups where they actively practice retrieval based on minimal cues. By reviewing, interpreting, and applying course material, students are more likely to build durable memories that are transferable to new situations.


• Link new material to what the student already knows.
  Students are much more likely to retrieve information that relates to ideas or experiences they already know. Spell out how new material relates to previous material. Use examples from student life, current events, or popular culture. Ask students to generate their own examples from personal experience. Show students how specific skills can be applied to real-world problems. Create class activities or assignments that ask students to fit new information into the overall themes of the course. Have students compare two schools of thought, synthesize competing perspectives, or discuss the evolution of one theory into another. Have them debate issues, play roles, carry out experiments, play games, brainstorm, discuss presentations and readings—in short, do anything that actively engages them with the material. By integrating new material into the student's existing knowledge base and experience, these techniques make it more likely that students will be able to remember and transfer the relevant information.


• Give 'em a break.
  Student attention during a lecture drops dramatically after ten minutes of listening (see Bligh). They remember most of the first ten minutes but much less from the middle part of a lecture. Give students short breaks throughout your lecture to review their notes and ask questions. A short break refreshes class attention, so students are more likely to remember information from throughout the lecture. This also gives you a chance to assess student understanding and to adjust the rest of the lecture as necessary. You can include a more formal activity or assignment after every 15-20 minutes of presentation. For example, ask students to summarize key points in their notes. You can then review the points and move on to the next phase of the lecture.


• Use tests to reinforce retrieval.
  Learning occurs at various stages—during the initial exposure to a lecture or text material, during a period of retention, and during retrieval. These together determine what's remembered and how much is transferable at some point in the future. Tests, even practice tests, are exercises in retrieval, reinforcing ideas and offering students valuable feedback. The act of remembering during tests strengthens some memory traces and weakens others. Asking students to recall specific information leads to selective forgetting of what they are not asked to recall. Testing for unimportant material increases the retention of that material at the expense of main points. Likewise, testing only recent material may yield higher test scores, but students become overconfident about their long-term retention, so they tend to study less for future tests. Consequently, tests should cover key concepts, not trivia, and should be cumulative during the term, not limited only to the most recent material.


• Raise key ideas again over time.
  Align your lectures, assignments, and tests so that key ideas are recalled at different times throughout the term. A spacing effect found by cognitive scientists indicates that review and testing sessions that are spaced out over time are more effective for long-term retention and transfer. While concentrated coverage of information produces better short-term performance, distributing coverage over time yields significantly better long-term performance. In fact, the long-term advantages of distributing coverage over time have been found repeatedly for more than a century of controlled research into human memory. For example, in a study by Glover of long-term retention, undergraduates were tested on either essay passages or labels for diagrams. When a single intervening test was administered immediately after the initial coverage, long-term benefits were minimal compared to when the intervening test was administered two days later. And when intervening tests were spaced, two tests were more effective than a single test at improving long-term retention. Instructors should present key points over time, then review them several weeks after the initial presentation.


• Vary the conditions of learning.
  Research by cognitive scientists find that when learning occurs under varying conditions, key ideas develop more pathways and are therefore more retrievable. Varying the learning conditions makes learning more challenging initially but yields deeper, more transferable understanding. For example, organize some lectures in a different way than the textbook. Also mix different types of problems and solutions in the same lesson, even though this takes longer and may frustrate some students. Learning is also enhanced when students translate information presented in one format into an alternative format. There is also some evidence that mixing up the study venue can improve recall (perhaps by developing alternative retrieval pathways for long-term memory). You might suggest to students that from time-to-time they vary where they study—library, dorm, home, study hall, or student union.


• Introduce "desirable difficulties".
  Desirable difficulties are challenges introduced during instruction that seem to benefit long-term learning. Teaching that appears to create difficulties for students, such as presenting material in different contexts and different formats, may seem to slow the apparent rate of learning in the short run, but this improves long-term retention and transfer. For example, in an experiment by Mannes & Kintsch, students were required to read an article about the industrial uses of microbes after first having studied an outline that was either consistent with the organization of the article or inconsistent with that organization (but offering the same information in either case). The inconsistent condition impaired verbatim recall and recognition of the article's content (compared to the consistent condition) but improved performance on tests that required students to solve problems based on their general understanding of the article's content. I'm not suggesting that you should purposely confuse students, but a lecture that challenges students engages them more and helps them learn. The benefit of desirable difficulties even applies to tests. Intervening tests help subsequent test performance, especially when intervening tests are of a different form than subsequent tests. Landauer & Bjork and Rea & Modigliani have found that mixing up the type of test seems to help students on later retrievals. More generally, the easier you make your course and the more uniform the tests, the less students seem to engage and learn. Putting your class notes online, for example, may make you feel like a student champion (and might improve your student evaluations), but presenting the course on a silver platter does not promote learning and transfer. You take one step forward, and students take one step back. Easy come, easy go.


• Be careful with multimedia, especially PowerPoint®.
  PowerPoint and other multimedia are abused when instructors overwhelm students with material while offering no cognitive guidance as to how it's to be learned. Slides can amount to an information dump—one numbing bullet point after another. We might first ask whether a PowerPoint slide is more effective than what you could sketch on a blackboard or overhead. In experiments by Stern and colleagues, one group was presented complete economics graphs while another group constructed graphs following the instructions provided. Questions were later posed that could be answered by recalling similar graphs. Two studies based on 281 subjects found that active graphical construction turned out to be a much more powerful transfer tool. Still, if multimedia seems like the preferred presentation mode, here are some guidelines, most of which were suggested by Mayer & Moreno. Keep in mind that people have separate information processing channels for visual-spatial material and for verbal material. Students learn better from words and spatial figures combined, than from words alone. Research suggests that more memory capacity is available when dual tracks are used. For example, we should talk students through a visual display, such as a graph, rather than include a written explanation on the exhibit. If an oral description is not possible, words should be presented next to the graph on the same screen. This allows for cognitive interaction. Students also learn better when extraneous material is excluded. Several studies show that the less relevant the pictures, clip-art, animations, or sound effects, the worse the students performed and the more they disliked PowerPoint. For example, Bartsch & Cobern found that students who attended PowerPoint presentations with sound and pictures performed worse than students who attended PowerPoint presentations without these elements (see also Sosin et al.). Finally, if material is presented in an intelligible format, such as your spoken voice, then the same information does not need repeating in another format, such as the written word. Jamet & Le Bohec found that when written sentences repeated spoken information, this duplication impaired subsequent retention and transfer.


• Student effort is critical to long-term retention and transfer.
  UC-Santa Barbara psychologist Richard Mayer argues that there is too much emphasis on differences across students in their ability to learn and too little emphasis on differences in student effort. What students do determines what and how much they learn, how well it's remembered, and under what conditions it's recalled and transferred. What we do in class matters less than what we ask and expect students to do in the course. For example, assigning a good textbook can help compensate for below average teaching. Student practice at retrieving is key. Remember, it's not what we teach—it's what they learn.


• Finally, begin with an end in mind.
  The level of detail that the student will need at some point in the future is what should guide us about what to cover in the course. If a cursory knowledge of a broad area is what's called for, then broader is better. If a deeper understanding of basic principles is what's needed, then teaching and learning need to be structured accordingly. Instructors and students should have clearly articulated goals. The course should not be like some giant Easter-egg hunt. Your intentions should be transparent—students should be able to see right through you.

Top                                                                                                                                                                                          Next