Verified by 
Key points
- Frequent quizzes promote learning of material.
- Grouping quiz questions by topic helps students recall information more easily.
- Interweaving questions from different topics on quizzes is hard at first, but leads to better long-term learning.
Last year, I finished my 31st year teaching at the university level. I have taught a variety of classes that include content from cognitive psychology and cognitive science. One thing that I tell my students is that cognitive psychology will confirm all of your worst fears about how to learn. You have to work hard and study early and often. I say that these are the worst fears of students because they are hoping that there will be an easy trick to learning new material.
Another interesting aspect of what cognitive psychology can teach is that students' beliefs about how they want a class to go often lead to worse performance than alternatives. This point was driven home to me when reading a May 2022 article in the journal Psychological Science by Faria Sana and Veronica Yan.
They compared two forms of tests in real science classrooms in Canada. For four weeks, students in a number of science classrooms learned a series of topics. Of six core topics each week, students were tested on three of those topics at the end of the week.
Half the time, the tests were structured so that the questions about the topics were presented in blocks. That is, students got all the questions about one topic, then all the questions about the second topic, then all the questions about the third topic.
The other half of the time, the questions were interleaved, so that a question on one topic was followed by a question on another topic, followed by a question on the third, and then this pattern was repeated.
My experience is that students prefer to get questions blocked together (just as they prefer to have final exams that focus only on the material in the last part of the class rather than finals that are cumulative across all of the topics covered across the semester).
A month after the last of the quizzes, students were given a final test covering both topics that were part of the weekly quizzes as well as topics that were never tested.
So, what happened?
Impact of quizzes with blocked vs. interleaved questions
First off, students are justified in wanting to get information on a quiz blocked rather than interleaved if you look at their performance on the weekly quiz. They did slightly better on the weekly quiz when each of the topics was tested together rather than when the questions were interleaved. This finding probably reflects that it is easier to retrieve information about a topic when you are already thinking about that topic than when you are thinking about something else.
That said, the rest of the results suggest that students' desire is not best for their long-term learning.
First off, weekly quizzes help (even though students hate those, too). That is, students did better on topics that were part of the weekly quizzes than on topics that were not quizzed.
Second, on the final test, students did better on topics that were presented in quizzes in which the information was interleaved than on topics that were presented in quizzes that were blocked.
Why would that happen?
Benefits of interleaved quizzes
You have to work a little harder to pull out information when the questions are presented in an interleaved fashion. As a result, you’re a little worse at it initially. But, that extra effort is rewarded later, because the information is learned better in the long run.
Essentially, students (like most people) would like to put in the minimum amount of effort needed to reach a goal. If the goal is getting a good grade (which is how a lot of school is set up), then it is better to have fewer quizzes, for those quizzes to focus only on information that was presented recently, and for the information to be presented in blocks.
But, a growing amount of work suggests that a moderate amount of difficulty and frustration during learning actually promotes good learning. So, the very factors that make learning and studying a little harder in the short-term lead to better long-term learning. Of course, it would help a lot if we focused less on grades than on learning in school. That might help to align what students want with what promotes the best learning in the long run.
References
Sana, F., & Yan, V. X. (2022). Interleaving Retrieval Practice Promotes Science Learning. Psychological Science, 33(5), 782–788. https://doi.org/10.1177/09567976211057507
Bjork E.L, Bjork R.A. (2011). Making things hard on yourself, but in a good way: creating desirable difficulties to
enhance learning. In Psychology and the Real World: Essays Illustrating Fundamental Contributions to Society,
ed. MA Gernsbacher, RW Pew, LM Hough, JR Pomerantz, pp. 56–64. New York: Worth
