Teach like a champion 3.0: 63 techniques that put students on the path to college - Lemov Doug 2021

Technique 7: Retrieval practice
Check for understanding

Forgetting is a constant problem in almost any setting that involves learning—so familiar and pervasive that we almost overlook it. Hours after demonstrating their understanding of juxtaposition in Romeo and Juliet or how to find the area of an irregular polygon, students may remember only a fraction of that knowledge. In a few days, they may have forgotten the majority of it. This simple if frequently overlooked fact is one of the most important considerations in teaching: Once students have initially learned something, they quickly begin to forget it.

You have probably seen this play out in your own classroom. On Tuesday you are confident in your students' skill and knowledge. They're solid on the what, why, and how. But when you assess them a week and a half later, it's as if Tuesday's lesson never happened. Then, Rodrigo completed five complex area problems with ease; now you glance over his shoulder and see that he has gotten even simple problems wrong.

There is a silver lining, however, to this persistent challenge. The process of forgetting contains the seeds of its own solution. If you ask students to recall what they learned yesterday about the area of polygons or juxtaposition in Romeo and Juliet they will strain to remember but if successful, that struggle will more deeply encode the material in their long-term memories. They will remember a little more and forget a little less quickly.

Retrieval Practice, or the process of causing students to recall information they've learned after a strategic delay, is a practical solution to the problem of forgetting. If you graphed the process of retrieval practice it might look something like this, with each repetition along the top axis an iteration of retrieval practice and the percentages on the y-axis representing how much of a given body of content students remember.

This illustration is an example of what's called a forgetting curve.¹ It represents the nature of forgetting as educational psychologists understand it. At point 1, the end of your lesson, students have acquired a certain amount of knowledge and skills. But as soon as the bell rings, the forgetting begins. And forgetting is a relentless enemy. Even a few minutes later some of the details will have gotten hazy. By the next day students will have forgotten even more—possibly more than half of what they learned. If steps aren't taken to arrest this process, they may lose most of what they know. On the curve, the process of unchecked forgetting is represented by line A.

Point 2, however, represents what happens when you come back to the content and review it. Perhaps this happens the next day. When you do so, students' knowledge is recalled into working memory. Having done so, their knowledge of it returns roughly to the level it was at by the end of the original lesson.

Of course, after this review, forgetting begins again. What students know again starts to slip away. The second downward sloping line (B) captures this. But the rate of forgetting is slower now and the line starts to flatten sooner—which suggests that more remains in long-term memory. If you review again, knowledge is refreshed and forgetting again resumes immediately after—represented by line C—but again the rate is slower yet and the floor (total amount of knowledge retained) is higher still.

As the cognitive psychologists Paul Kirschner, John Sweller, and Richard Clark write: “The aim of all instruction is to alter long-term memory. If nothing has changed in long-term memory, nothing has been learned.”² If we spent an hour studying the systems of the human body only to have students forget it—a day later, a week later, a month later—then the lesson might have been interesting and engaging, but students would have learned precious little. Even the deepest and most profound discussions remain at risk of evaporating as if into ether. As Harry Fletcher Wood puts it, “Student performance while being taught is a poor indicator of lasting learning.” We should by all means check for understanding at the end of a lesson. But just because students appear to know something at the end of that hour does not mean they will know it in a week, a month, or a year. If we want lasting learning, we have to get things into long-term memory, and retrieval practice is the best way to do that.

Since the concept of Retrieval Practice is discussed throughout cognitive psychology in a wide variety of contexts, the following is a useful “teacher's definition.”

Retrieval Practice occurs when learners recall and apply multiple examples of previously learned knowledge or skills after a period of forgetting. This definition suggests two key things. First: intentionality. You might say, “Oh, asking kids about concepts we previously learned? I do that all the time,” but what we're talking about here is more than just occasional episodic review—“Remember how we talked about juxtaposition when we read Romeo and Juliet?” It's the strategic use of retrieval, systematically and regularly. This might even mean Retrieval Practice becomes a discrete part of your lessons—a chunk of time you design with the explicit purpose of causing students to recall important things in strategic ways, probably using tools like Cold Call and Call and Response to ensure that every student recalls the requisite information. Retrieval in these settings need not be simplistic or rote. A bit of challenge is beneficial, so changing formats or asking students to apply concepts in new ways is likely to help.

Second, the definition suggests strategic delay. Notice on the Forgetting Curve that the delay between rounds of retrieval increases slightly each time. Gradually increasing the intervals between rounds of retrieval aids memory because the best time to remember something is when you have begun to forget it, and the rate of our forgetting is constantly changing. And if nothing else, a glance at the Forgetting Curve should confirm that it is almost impossible to master a concept in a durable and enduring way in a single lesson.³

You might be tempted to think of Retrieval Practice as a recipe for mere rote memorization, but this is not the case. Retrieval is an opportunity for what Brown, Roediger, and McDaniel call “elaboration”: connecting an idea to other ideas, reflecting on it, and expanding it as you review it. Elaboration aids in retrieval, in fact.⁴ When a concept is connected to other related ideas and when students can describe it in different ways, it becomes more powerful. So you might, in reviewing juxtaposition, deliberately ask for elaboration. “Asha, what's juxtaposition? Darius, what's an example from Romeo and Juliet? Katie, what's another? Roberto, what's another example of two characters who are juxtaposed from something else we've read? Good, and Kyra, in your own words, why might an author use juxtaposition?” The elaboration, causing students to explain and put into new words, to make connections, increases their knowledge of the concept and the likelihood that they will remember it when they need it.

The first half of the video Christine Torres: Keystone is a great example of other ways that Retrieval Practice can work. Christine is reviewing vocabulary words with students. Notice the richness of the questions Christine asks. Retrieval Practice questions don't have to be simple recall. Christine asks her students to apply the vocabulary words they're learning in different ways and new settings. That's important, because words work differently in different settings. To truly understand a word, you'd want students to constantly encounter it in all its nuanced shades of meaning. Christine asks students to know the definition, but also to apply the word in challenging and interesting ways. It's both simple and more elaborated retrieval. Christine makes sure that every student wrestles with almost every question. She uses Turn and Talk (see technique 43). For retrieval practice, we can't just take hands from volunteers or let a few highly verbal kids call out answers. We need to cause everyone to remember and apply the concept.

Interestingly, the period of delay between initial learning and retrieval is short in Christine's classroom. Forgetting, she knows, starts right away. With challenging and potentially confusing concepts, especially, it's not too soon to begin retrieving right away. So even though students learned what the words meant just a few minutes ago, Christine is already trying to get them into long-term memory. And Christine will be sure to follow up the next day and/or a few days later—and again a few days after that—with more fun and engaging questions to retrieve and apply their knowledge of their vocabulary words. She also frequently includes previously mastered vocabulary words when she's retrieving new words. In this way they will have both depth and richness of understanding and long-term memory of the words.

It's not just that more of the original material remains in long-term memory that matters with Retrieval Practice. It's that the knowledge that is there is easier for students to recall. After three rounds of review, the neural pathways back to those discussions about juxtaposition in Romeo and Juliet, for example, are well worn. When students come upon an example of juxtaposition in some other text they are reading, the examples from Shakespeare will snap readily to mind. They will form connections. Easier retrieval leads to more than just knowing facts, in other words. Having various models of juxtaposition that come easily and naturally to mind becomes a schema—a connected body of knowledge that becomes familiar enough that people can use it quickly and easily to process information at minimal load to working memory as they interact with the world around them. Knowledge in that form—encoded in long-term memory and easily accessed—helps students perceive and understand more. This is one key reason why educational psychologists like Daniel Willingham remind us that knowledge easily accessed in long-term memory is the key to higher-order thinking.⁵ The best way to maximize the capacity of working memory for higher-order thinking, as I discussed in Chapter One, is to give it access to lots of ideas in long-term memory that it can draw upon.⁶

You can see some unexpected benefits of retrieval practice in the video Lauren Moyle: Cranium. Lauren here is asking her first-grade students to retrieve into active memory key details about the body. The brain is an essential organ that controls our decision making. It is encased in a bone called the cranium. The heart is a pump that distributes blood to the body like an engine. You can see them recalling the pieces of this content in different ways: What's it called, Why is it called that, What does it do? Every child is engaged with the task.

Interestingly this video is about ten years old and only recently did I come to understand it! We used to show it at workshops, inspired by Lauren's dynamic teaching—the questioning that fostered eager hands supported by the use of Cold Call and with No Opt Out, to ensure accountability and engagement. We were focused on how Lauren taught and didn't spend much time thinking about the value of what she was doing. In fact, ironically, when what she was teaching came up in discussions at workshops, I often found myself apologizing for it. Participants would occasionally note that she was just recalling facts, the phrase implying there wasn't much substantive teaching going on. Eventually we stopped showing the video altogether.

Now I can see much more clearly that what Lauren is doing is at least as valuable as how she's doing it. Future discussions in her class will be richer and based on firm knowledge because of what she does here. The other unexpected thing the video shows is how much students tend to like Retrieval Practice. Lauren's students are eager, happy, and confident. Teachers sometimes presume that facts are boring for students and so focusing on retrieval practice will make their classes dull, but the opposite is often the case. Students who know their material are proud to know it and eager to use it. And as they begin they see examples of what they know in more and more places, their confidence grows, often transferring to more complicated tasks in which they are asked to put those facts to use.

I'll close the discussion of Retrieval Practice by sharing a video, Retrieval Practice Montage, of several teachers employing the concept in different ways. Art Worrell's AP U.S. History students stand to answer his retrieval questions. It's a regular and intentional part of the day and the importance of Retrieval Practice is transparent to students. This helps them to understand how important it is for them to use in their own studying! Art again undercuts the idea that Retrieval Practice questions have to be simple. He asks Tarik what the compromise of 1877 was, but also why it was important. He then asks Kamari to expand on Tarik's answer. As Kamari's answer shows, it's broad knowledge, not just narrow facts, that they're recalling.

Annette Riffle uses Retrieval Practice in her middle school math classroom to make ideal use of what might otherwise be down time—one student is at the board modeling a problem and, rather than allowing everyone else to sit passively, she peppers them with key questions about coordinate geometry.

Barry Smith's use of Retrieval Practice in his French class shows two things: first, a variety of ways to engage—Cold Call, Call and Response, hands raised—and also that the content goes in two directions. Barry asks his students to go both from French to English and English to French. Teachers of other content areas might think about naming a concept and asking students to describe it and then flipping the process: describing a concept and asking students to name it, asking, for example, “What is hyperbole?”; “What is it called when authors intentionally exaggerate to make a point?”; and perhaps even “If I say I've got a million things to do today, what literary device am I using?” All of these strengthen the neural pathway.

Finally, Alonte Johnson reminds us in his literature classroom that we can ask students to retrieve a full range of content types: plot, character, background knowledge, and even themes.