What 10 minutes a week can do

Let’s be honest: as a teacher, you want more than students who can recite definitions or repeat tricks. You want them to understand why something works, remember when it’s relevant, and apply how to use it — even in unfamiliar situations.

Take physics, for example: it’s not just about knowing the difference between a series and a parallel circuit, but about recognising which type of circuit fits a particular situation, and why.

And there’s the challenge: deep understanding often fades faster than we’d like. What seems clear today can already be vague by next week — let alone next month. Unfortunately, many textbooks and curricula unintentionally contribute to this problem by promoting blocked instruction and practice: covering one topic at a time, in neat order, with as little interference as possible.

But what if that very interference — that “noise” — is actually the key?

The study by Sana and Yan (2022) combines two well-established principles from cognitive psychology: retrieval practice and interleaving. Retrieval practice involves actively recalling information from memory — for example, through a quiz or no-stakes test (aimed at learning, not grading). Interleaving means mixing together related topics (such as different styles of expressionist painting or types of electrical circuits), instead of practising one topic in full before moving on to the next.

Each of these strategies is proven effective on its own. But in this study, they were combined and — crucially — implemented in real classrooms. Not a lab study with volunteers, but actual students and teachers at a Canadian secondary school. That makes the findings all the more relevant to everyday teaching.

What did they do?

In this study, students from eight classes (grades 9–12, across subjects like biology, physics, and chemistry) completed a short quiz at the end of each week for four weeks. Each quiz lasted no more than 10 to 12 minutes. For each quiz, teachers selected three concepts that had been taught that week and were known to be challenging for students. Half the quizzes presented the questions in blocked order — all questions on concept A, followed by B, then C. The other half used interleaved order — questions on A, B, and C shuffled together.

One month after the final quiz, students were given a surprise test on the same concepts. The results were clear: concepts that had been quizzed were remembered better than those that had not been practised. Even more strikingly, concepts practised with interleaved quizzes were remembered best of all. The learning gains were substantial — even compared to many other educational interventions.

“But it felt harder!”

Interestingly, students found the interleaved quizzes more difficult and initially performed worse on them than on the blocked ones. That might seem like a drawback, but it isn’t. That very sense of difficulty — the constant switching between concepts, the need to reactivate knowledge again and again — turns out to be a powerful driver of long-term learning.

Robert and Elizabeth Bjork call this kind of challenge a desirable difficulty: an obstacle that actually improves learning. When the brain has to work harder, it encodes more deeply. In contrast, when learning feels too easy, it often stays superficial. The harder the effort, the more durable the memory.

What does this mean for your classroom?

The good news is: you don’t need to overhaul your teaching. This approach is remarkably simple to implement. You could start by adding a short quiz at the end of each teaching week — no more than ten to twelve minutes. Choose three key concepts from that week, ideally ones your students tend to confuse or find difficult. Use questions you already have — from the textbook, your test archive, or past exams — and present them in a mixed-up order. Have students take the quiz without giving it a grade. Don’t treat it as an assessment, but as a learning activity. And there’s no need to give immediate feedback; the act of recalling from memory is already doing the heavy lifting.

Try this approach for four weeks and you’ll likely notice a difference. Students will not only retain more, but their understanding will deepen. It requires almost no extra time, yet delivers powerful results.

In short: low effort, high impact

This study shows that a small investment of time and effort can make a big difference in student learning. You don’t need to rewrite your curriculum, buy new materials, or attend additional training. What you do need is to make regular room for active processing — and that starts with something as simple as a well-designed quiz.

It may take some getting used to — for both you and your students — but it’s well worth it. Understanding grows. Knowledge sticks. And best of all, you don’t even have to give up a full lesson to make it happen.

Sana, F., & Yan, V. X. (2022). Interleaving retrieval practice promotes science learning. Psychological Science, 33(5), 782–788. https://doi.org/10.1177/09567976211057507