Center for Teaching and Learning

How People Learn

Effective teaching is less about the perfect delivery of information and more about aligning our instructional choices with the cognitive realities of our students. This page offers a brief introduction to several key concepts—from the "illusion of explanatory depth" that can mask a lack of understanding, to the transformative power of engaging students in making predictions and quizzing themselves on their reading.

While this overview is far from comprehensive, these research-backed insights offer a starting point for reflection. We invite you to explore these concepts not as rigid rules, but as ideas to help you modify your course design or teaching practices to better support how students actually process, retain, and apply new knowledge.

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The Illusion of Explanatory Depth

While some of the criticism of lecturing that appears in the literature on teaching and learning is overblown, the illusion of explanatory depth is one quite serious problem with non-interactive lectures. Simply put, it refers to the finding that students tend to confuse their ability to follow along with an expert's explanation of a concept/method for their own mastery of that concept/method, with the result that they often discover (too late) that they do not know nearly as much as they think they know about the material, and cannot spontaneously reproduce the expert’s performance by themselves. If you've ever watched a cooking demonstration and come away convinced that you will be able to execute the recipe, only to discover that you need to rewatch the video at almost every step, you’ve experienced this illusion.

What it means for instructors … We need to make sure that we are making our lectures interactive, pausing frequently to compel our students to practice or recapitulate what we have just shown them in their own words or with their own hands before proceeding to the next step or topic. This method of interactive teaching, in which students engage in problem-solving in tandem with (or even in substitution of) our lecturing, is commonly called active learning, and there is abundant evidence that it significantly improves student outcomes and retention (even if students do not always appreciate this fact).

Attention Span

There is a considerable amount of research on attention span, with quite a range of results. It's likely safest to assume that average human attention span falls somewhere in the range of 10–12 minutes. This does not mean that instructors must change their topic every 10–12 minutes; rather, it means that something in their students' environment must shift on that timescale—for instance, that lecture should give way to a brief activity or poll question, or that a segment of group work time should not last uninterrupted for longer than 10–15 minutes.

What it means for instructors … We need to make sure that we are varying the kinds of activities that occur in our classrooms several times over the course of every hour, irrespective of their merit—i.e. even active learning, for all of its advantages, loses its efficacy after a relatively brief period of time. 

The Power of Prediction

Most instruction is sequenced as follows: instructor introduces concept → instructor explains concept → students practice/apply concept. While this makes a certain kind of logical sense, it also neglects the vital role of student motivation, assuming that students will be interested in the material just because the instructor put it on the syllabus. Research has shown that students pay more attention to their instructors' explanations, and learn more, when they are asked to create their own explanations (or solve a problem) before receiving instruction, even in spite of the fact that—by definition—they will become stuck or fail. The simple act of making a prediction about the material they will be taught “hooks” students into the subject, harnessing their intrinsic motivation and increasing learning.

What it means for instructors … We should reverse the conventional order of instruction, presenting students with a problem or application of what we are about to teach them before we have explained it. This allows them to discover for themselves why the problem is interesting, and the limits of their own knowledge, and creates an authentic desire to know and to understand what they are about to be taught.

The Mixed Evidence for “Flipped” Classrooms

Around two decades ago, instructors teaching large lecture courses at public universities without adequate instructional support reported increases in student success when they "flipped" their classrooms, transforming their lectures into pre-recorded videos to be watched outside of class so that students could spend their in-class time engaged in interactive problem-solving practice. By reorganizing their material in this way, instructors found that they were able to provide much more tailored, just-in-time guidance to students who were stuck or confused, compensating for their lack of TAs and meaningful contact hours. Given its demonstrated success at large institutions, "flipping" became a popular practice in STEM classrooms across US higher education. Yet many institutions did not see the same kinds of learning gains as the early adopters had reported—perhaps because subsequent adopters assumed that the mere act of flipping would guarantee success, and thus did not devote enough time to making sure that the in-person class time they had reclaimed by moving their lectures to video was truly interactive and well-designed to promote learning.

What it means for instructors … We should not assume that simply swapping conventional lectures for generic “active learning” lesson plans automatically leads to improved learning. Instead, we must be thoughtful about how we use group work, problem solving, and other forms of classroom interactivity to make sure that students are compelled to recall, practice, apply, and internalize the concepts and methods we intend to teach them. It might be a good sign if the students in a classroom are spending much of their time talking with each other—but only if that talking is in service of a lesson plan that is well-aligned with the instructor’s goals.

Retrieval Practice

It turns out that the best way to make sure that a concept is retained in long term memory is not simply to review it passively a number of times (for example, by reading and then re-reading a textbook chapter before the exam). Rather, we must also make at least as many attempts to retrieve the concept from memory—to pull it back out of our minds—as we do to load it in the first place. In its simplest form, this means quizzing or testing ourselves (and the benefit of retrieval practice is sometimes called the "testing effect" in pedagogical literature). This is often unwelcome news to students, as they (like all humans) would probably much rather read something two or even three times than to make flashcards and quiz themselves, since quizzing feels like hard work (which, in fact, it is—in the best way).

What it means for instructors … We would do well to build in as many opportunities for quizzing (including low- or no-stakes self-quizzing) into our courses as possible. If you are worried about students coming to class prepared to discuss the reading, for example, you might create a short, ungraded quiz in Moodle, to be completed before students come to class, that compels them to retrieve the main points or key terms from the reading once or twice in order to "unlock" a handout that they need to bring to the class discussion. At the very least, it would be in your interest to remind students regularly throughout the term that the most effective way to study is not to re-read the course materials, but rather to quiz themselves on them.

Spacing and Interleaving

These two concepts have to do with how we sequence material across the semester. Spacing refers to the (unsurprising) finding that, however well short-term cramming might work to pass a single exam, the only way for students to optimize for long-term retention is to study a subject at intervals spaced out across a longer span of time. It is much more effective to study for 1 hour/day than for 5 hours in a single day. Interleaving refers to the finding that, when we set out to learn multiple concepts (let's call them A, B, and C), the most effective way to do so is to study A, then B, then A+B, then C, then A+B+C, and so on, revisiting earlier concepts frequently even as new ones are introduced. This is something that effective elementary school math teachers learn—that rather than teaching a unit on addition, then a unit on subtraction, then multiplication, and so on, they should make sure that addition problems are interleaved into the subtraction unit, etc.

What it means for instructors … We should make sure when designing our courses to sequence material and concepts in a way that guarantees that students are revisiting things they learned earlier in the semester multiple times as the semester advances, always integrating new concepts into the existing material with which students have become familiar. This is as true of assessments, like exams, as it is of homework and in-class activities. It is important that courses with multiple midterms not “forget” about material covered on earlier midterms until it reappears all at once on a cumulative final exam.

Four Determinants of Student Motivation

Research has shown that Agency, Value, Expectancy, and Environment play a major role in shaping student motivation.

  • Agency refers to the extent to which students feel that they have a say in their learning—in what they learn and/or how they are asked to learn it. While faculty should determine the overall plan for a course, allowing students some freedom to choose among topics, or to explore them in different ways or mediums, can help students feel that they have a stake in shaping their own educations.
  • Value refers to the extent to which students believe that the course material is important and useful to them. Students may be significantly more motivated to engage in learning when they see (e.g.) the practical, "real world" implications of what you are teaching them.
  • Expectancy refers to the extent to which students believe that they can succeed in a course if they follow the plan articulated by the instructor. While instructors ideally design courses that ask students to stretch beyond their current sense of what is possible/comfortable, that stretch should not be so great as to be discouraging.
  • Environment refers to the extent to which students feel that they are part of a supportive community—one in which their instructors and peers value their unique contributions, will not hold their mistakes or failures against them, and want them to succeed.
What it means for instructors … We should adopt practices and policies that "activate" these four drivers of student motivation—giving students agency to help define the scope of the course (e.g. by letting them nominate or choose between some topics or readings), helping them to see the value of what they are learning (e.g. by connecting lessons to real-world figures and events), setting realistic goals and showing them the steps by which to attain them, and creating a supportive environment (e.g. by co-creating a class contract or group agreement at the start of the term).

Further Reading