Spaced Retrieval Practice Benefits Long-Term Learning and Transfer
By Megan Sumeracki
For over a century cognitive psychologists have been studying spaced practice and retrieval practice, resulting in a great deal of evidence that these two strategies work very well to improve student learning. However, no single experiment or paper is going to be able to answer, in full, the question “how does this strategy work in education?”. When we point to a single experiment, or even a set of experiments, it can be quite easy to point out the ways in which the experiment(s) may not be a perfect test of the phenomenon, or might not measure everything we want to measure. Each experiment or set of experiments has strengths and limitations, but by conducting the research in a lot of different ways, we gain more confidence in the recommendations and better understand the way these processes work. (Of course, we still have plenty of work to do as not every nuanced question has been answered.)
There are a few common criticisms of retrieval practice and spaced practice experiments that come up frequently. One is that we often use very simple materials. We explain why this is necessary when we write or talk about the lab-to-classroom model (see this post). However, even when we engage in applied laboratory and applied classroom research, the criticism often becomes that we are only looking at relatively short-term learning (e.g., a few days or weeks) and/or that we are measuring things like memorization, simple remembering, or fact learning. I would argue that learning and remembering facts is important, and the basis for being able to then apply that information in new settings (see this piece by Daniel Willingham). However, the research really does not stop at “memorization”! Many experiments have investigated what strategies help students make inferences, apply what they have learned to new problems or situations, and to generally transfer what they have learned (see this post and this post to read more about transfer). Again, while we have not answered all of the questions, I am confident in saying that spaced practice and retrieval practice do generally help students truly learn and apply what they have learned even after a longer delay.
In the spirit of addressing true student learning and their ability to take what they have learned with them into new situations, today’s blog covers a paper by Robin Hopkins and colleagues (1). They asked whether spaced retrieval practice throughout a precalculus class would help engineering students learn precalculus and perform better on the precalculus course’ cumulative final exam, and whether spaced retrieval practice during precalculus would better prepare them for the following semester’s calculus class.
Overall, what the results show is that yes, spaced retrieval practice during precalculus does lead to better performance in (1) precalculus and (2) on a cumulative final exam in the next semester’s calculus course many months later! This experiment is impressive. Read on to learn about the overall experimental methods and results.
Image from Pexels, Yan Krukov
The Experimental Design and Procedure
The participants were university engineering students enrolled in a precalculus class. All students in the experiment were taught by the same instructor and had the same content covered in class meetings and course requirements. All of the students took weekly quizzes as a part of the class.
The researchers used a hybrid design so that they could examine the effects of spaced retrieval practice both between-subjects* and within-subjects* in the same experiment. The researchers did this because they wanted to know whether spaced retrieval practice for some concepts might improve learning for other related concepts.
The engineering authors of the paper also identified the most important learning objectives in the course. They selected 48 objectives that are foundational to the mathematics sequence in the engineering program. Students were then randomly assigned to either the control group or the experimental group. In the control group of students, retrieval practice for all of the learning objectives was massed, and in the experimental group of students, retrieval practice for half of the learning objectives was massed and for the other half was spaced (counterbalanced* to account for differences in difficulty).
Massed Retrieval Practice: In this condition, students answered multiple quiz questions for each learning objective, and all of the questions for the objective were assigned within the same weekly quiz.
Spaced Retrieval Practice: In this condition, students answered multiple quiz questions for each learning objective, but each question for the objective was assigned within a different weekly quiz. Therefore, when the students were in this condition, they practiced retrieval of the learning objective spread out over multiple quizzes across multiple weeks.
The researchers measured learning by examining performance on various exams for each learning objective in the experiment. Importantly, the researchers analyzed learning on the cumulative final exam at the end of the precalculus course, and on exams given in the second semester in the series, a calculus class required by all Engineering students. In this way, the design can inform whether spaced retrieval practice helped students learn in the long-term, and transfer their knowledge to the next course within an essential sequence.
*For a review of research methods, see this blog. The “True Experiment” section covers these terms!
The Results
Precalculus learning
Students performed better on the cumulative final exam in their precalculus class when they learned the material with spaced retrieval practice, rather than massed.
Looking only at the massed learning objectives on the cumulative final exam: Those in the experimental condition performed better than those in the control for the massed learning objectives. (Note for our research readers: the p-value was .058, but the authors make the case for a true effect, while also acknowledging alternate explanations.) This finding suggests that learning some of the content through spaced retrieval practice “spilled over” into learning some of the other content better, good news for educators!
Calculus learning the following semester
Students who were in the experimental group, and thus had spaced retrieval practice during precalculus, performed numerically better on the first unit exam in their next semester's calculus course, though this difference was not statistically significant. This particular unit exam was important to examine because it covered a lot of the concepts from precalculus.
Students who were in the experimental group, and thus had spaced retrieval practice during precalculus, performed better on the cumulative final exam in their next semester's calculus course.
Students from the experimental group, who experienced spaced retrieval practice during precalculus, were much more likely to earn a satisfactory grade (C or better on an A-F scale with +/- grades) than those who only experienced massed retrieval practice.
Bottom Line
Engaging in spaced retrieval practice during precalculus led to greater learning than engaging in massed retrieval practice in a precalculus course for engineers. Most importantly, these differences carried over into the next semester when students took Calculus. Thus, spaced retrieval practice did not just help the students memorize precalculus content, but rather helped them learn and transfer what they learned into future courses within their program of study!
Image from Pexels, Monstera
References:
(1) Hopkins, R. F., Lyle, K. B., Hieb, J. L., & Ralston, P. A. S. (2016). Spaced retrieval practice increases college students’ short- and long-term retention of mathematics knowledge. Educational Psychology Review, 28(4), 853-873. https://doi.org/10.1007/s10648-015-9349-8
