A problem teachers face when delivering lectures is the issue of “transience.” Information is transient when elements of information that must be processed by a learner disappear to be replaced by new elements (Wong et al., 2019). You can simulate the experience of transient information yourself by taking a simple digit span test; Most of us can remember a string of 4-5 random digits without much difficulty, but increase the digit span any more and working memory becomes overloaded. In a similar way, non-interactive lectures containing a continuous flow of novel information will overload students because there are limits to how many elements of information they can process at a time.
Of course, we shouldn’t stop explaining things to students because of the limitations of working memory when dealing with transient information. Instead, we should find ways to reduce the transience of information by making presented information more permanent. Two ways to do this include: 1. Segmenting presentations and 2. Providing students with permanent materials, such as worked examples and diagrams.
One way to reduce transient information is to break lectures into manageable segments. I find it useful to think of lectures as alternating between two distinct types of segments: Input segments and output segments*. An input segment is the part when the teacher presents a chunk of information, such as an example or an explanation. These should be crystal clear, concise, and unambiguous. An output segment is an opportunity for students to participate, such as answer a question, write something down, or share with a partner. Choral response works well for short responses (1-2 words), mini-whiteboards are good for medium-length responses and quick drawings, and think-pair-share, cold calling, and “stop and jot” are more appropriate when responses are meant to be several sentences.
Breaking up lectures into alternating segments of inputs and outputs brings permanence to the information by ensuring that each bit of presented information is fully processed in working memory before it is replaced with the next bit.
Using Permanent Materials (e.g., Worked Examples and Diagrams)
Another way to reduce the negative impact of transient information on learning is to provide the information in a permanent format. Instead of orally describing the material, the teacher can distribute or project a diagram or a worked example, such as these below.
While most textbooks and online learning platforms (e.g., IXL or Khan Academy) use lots of diagrams and worked examples, it wasn’t until recently that I decided to be a bit more intentional about incorporating these materials into my regular lessons. In addition to explaining something on the whiteboard by progressively adding elements of information one at a time, I will sometimes ask students to study whole diagrams/worked examples in silence. Sometimes I project the diagram/worked example on the screen, and other times I distribute it by LMS or on paper. Either way, I use a routine to ensure that students cognitively engage with the material that goes something like this:
Stop: I say, In a moment I am going to project a worked example/diagram and I am going to have you study it in silence. I want you to put all of your mental effort into acquiring the information I am projecting.
Study: Once everyone’s eyes and body are focused towards the front, I project the worked example/diagram and say, You may begin. I stand in one place and do “Be Seen Looking” to keep expectations high for this activity.
Signal: Once they’ve studied the material, hard, for 1 minute (or a bit longer/shorter depending on what it is), I say Eyes on me and I proceed to integrate the worked example/diagram into my lecture by using my hand to signal to the individual parts that students are to be thinking about.
Explanations help with the construction of knowledge, but a non-stop, non-interactive lecture consisting entirely of transient information presented orally will likely go in one ear and out the other. Two ways to improve lectures include breaking presentations up by alternating between explanations and opportunities to interact with the material, and using permanent materials such as diagrams and worked examples.
Are you interested in finding out more ways that research can help improve your presentations? Come check out my March 2022 webinar with InnerDrive, here, on applying cognitive load theory to teaching.
Wong, M., Castro-Alonso, J. C., Ayres, P., & Paas, F. (2019). The effects of transient information and element interactivity on learning from instructional animations. Advances in Cognitive Load Theory, August 2019, 80–88. https://doi.org/10.4324/9780429283895-7