Research strongly indicates that human attention span begins to evaporate somewhere between 10-15 minutes (Bligh, 2000; Bonwell & Eison, 1991; Middendorf & Kalish, 1996). It follows that an effective lecture is one that is divided into a series of mini-lectures – 20 minutes at the most – with short (2-5 minutes) exercises in between that support student learning. Incidentally, this is the reasoning behind the 18 minute TED Talk format.
If the thought of removing twenty minutes from your ninety-minute lecture puts you off, know that if your lecture is that long, no matter how great an orator you may be, most of your students are tuning in and out for the majority of the time that you are speaking. Many of your words are simply floating over their heads as your students struggle to refocus their attention.
Short and simple exercises in between mini-lectures can provide both a 'brain break', allowing students to reset, and an opportunity to self or peer-check their comprehension. Here are some examples from Linda Nilson's excellent book*, Teaching at its Best: A Research-Based Resource for College Instructors (2016, pp. 147-149).
Pair and Compare
Students pair off with their neighbor and compare lecture notes, filling in what they have have missed. This activity makes students review and mentally process your mini-lecture content. Time: 2 minutes.
Pair, Compare, and Ask
This is the same as pair and compare but with the addition that students jot down questions on your mini-lecture content. Students answer one another's questions; then you field the remaining ones. Time: 3 minutes, plus 1 to 2 minutes to answer questions.
Periodic Free-Recall, with Pair-and-Compare Option
Students put away their lecture notes and write down the most important one, two, or three points of your mini-lecture, as well as any questions they have. The first two times you do this, use a slide, overhead, or the board to give instructions. After that, just telling them will do. Again, this activity makes students review and mentally process your mini-lecture content. Students may work individually, but if they work in pairs or triads, they can answer some of each other's questions. Time: 3 minutes, plus 1 to 2 minutes to answer students' questions.
Active Listening Checks
This is the same as the previous activity, except that you have your students hand in their three most important points, and then you reveal what you intended as most important. Lovett (2008), the researcher who devised this activity, uses it to improve her students' listening and note-taking skills. From the first time she did this in class to the third time, the percentage of students who correctly identified her three most important points rose from 45 to 75 percent. Time: 2 to 3 minutes
Students individually write out their affective reaction to the mini-lecture content (or video or demonstration). Ask a few volunteers to share. Time: 3 to 4 minutes.
Solve a Problem
Students solve an equational or word problem based on your mini-lecture. They can work individually or, better yet, in pairs or triads. Randomly call on a few individuals or groups to sample their answers. Time: 1 to 3 minutes for problem solving, depending on the problem's complexity, plus 1 to 2 minutes for surveying responses.
Put a multiple-choice item, preferably a conceptual or application type, related to your mini-lecture on the board or a slide, and give four response options. Survey your students' response options. You can also ask students to rate their confidence level in their answer. Then given them a minute to convince their neighbor of their answer, and resurvey their responses. This activity makes students apply and discuss your mini-lecture content while it's fresh in their minds, and it immediately informs you how well they have understood the material. You can then clarify misconceptions before proceeding to new material. Time: 3 minutes, plus 1 to 3 minutes to debrief and answer questions.
Multiple-Choice Test Item
In contrast to the previous multiple-choice item task, this one puts students in pairs or small groups to compose multiple-choice items on your mini-lecture for a test you will give in the future. As we know, this is no easy task, so provide your students with some training in good test-item writing. Teach them Bloom’s taxonomy. Tell them the characteristics of possible distractors. Show them examples of well-constructed and poorly constructed items, then lower-order recall and higher-order thinking items. Students will be motivated to write test items you will want to use because they will know the answers to the ones they submitted. And you will never have to write multiple-choice items again. Nor will students ever again blame you for items they find tricky, ambiguous, or too hard. Of course, you should reserve the right to tweak their submissions. Time: 1 to 3 minutes for each item they write.
Listen, Recall, and Ask; Then Pair, Compare, and Answer
Students only listen to your mini-lecture, no more talking allowed. Then they open their notebooks and write down all the major points they can recall, as well as any questions they have. Instruct students to leave generous space between the major points they write down. Finally, they pair off with their neighbor and compare lecture notes, filling in what they may have missed and answering one another’s questions. Again, this activity makes students test themselves, and practice retrieval of your lecture content. Time: 3 to 4 minutes for individual note writing plus 2 to 4 minutes for pair fill-ins and question answering.
Students develop a concept map, mind map, thinking map, graphic organizer, picture, diagram, flow-chart, or matrix of your mini-lecture content in pairs or small groups. What they are actually doing is integrating and reassembling their understanding of the content into a big-picture graphic. It is one of the purest constructivist activities you can have them do, and it yields powerful learning benefits. Because these graphics provide you with deep insight into your students’ interpretation of the material, you may want to collect and peruse them. You may also want to return them with some feedback – at the very least, pointing out any misconceptions and oversimplifications they reveal. Time: 3 to 10 minutes in class.
Quick Case Study
Students debrief a short case study (one to four paragraphs) that requires them to apply your mini-lecture content to a realistic, problematic situation. Display a very brief case on a slide; put longer ones in a handout. You may add specific questions for students to answer or teach your class the standard debriefing formula: What is the problem? What is the remedy? What is the prevention? Instruct students to jot down their answers. Students can work individually or, better yet, in pairs or small groups. Time: 3 to 5 minutes, depending on the case length or complexity, plus 5 to 10 minutes for class exchange and discussion.
Pair/Group and Review
This is the same as the previous activity but with an essay question designed for pre-exam review. Randomly select student pairs or groups to present their answers to the class. Then mock-grade them based on your assessment criteria (explain these before the exercise). You can also have the rest of the class mock-grade these answers to help students learn how to assess their work. Time: 3 to 10 minutes, depending on the question’s complexity, plus 5 to 15 minutes for pair/group presentations.
For more strategies, see page 149 of Linda Nilson's book, Teaching at its Best.
*Source: Nilson, L. (2016). Teaching at its best: A research-based resource for college instructors (4th ed.). San Francisco, CA: Jossey-Bass. Copyright 2016 by Copyright Holder. Used with permission.