Most math textbooks follow this structure: Chapter 1 — 20 linear equation problems. Chapter 2 — 20 quadratic equation problems. Intuitively, this seems right. But cognitive science research shows this approach is not optimal.
Blocked Practice vs. Interleaving
Blocked Practice means solving the same type of problem repeatedly in sequence: A, A, A, A, B, B, B, B.
Related: exercise for longevity
Interleaving means mixing different types of problems: A, B, C, A, C, B.
In a study by Rohrer & Taylor (2007), the blocked practice group performed better immediately after practice. But in a test one week later, the interleaving group significantly outperformed them.
Rohrer, D., & Taylor, K. (2007). The shuffling of mathematics problems improves learning. Instructional Science, 35(6), 481–498.
Why Is Interleaving More Effective?
In blocked practice, you already know which method to use. In interleaving, you must first ask yourself, “What type of problem is this?” every single time. That identification process is itself a core skill — because on real exams, students must classify problem types on their own.
Applying Interleaving in an Earth Science Classroom
Instead of giving chapter-specific quizzes in Earth Science, I created mixed review sheets that combined concepts from multiple chapters. At first, students were confused: “Which chapter does this come from?” That confusion was exactly the point. Scores were lower in the first few weeks, but a month later, retention improved dramatically.
The Interleaving Paradox
Kornell & Bjork (2008) found that even though interleaving was more effective, most students felt that blocked practice was more effective. Their perception was the opposite of reality.
Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories. Psychological Science, 19(6), 585–592.
ADHD and Interleaving
The ADHD brain gets bored quickly with repetitive patterns. Interleaving can actually be a better fit for ADHD brains, since every problem presents a new challenge. That said, blocked practice is still necessary when learning a concept for the first time.
Key Takeaways
Blocked practice is good for immediate performance but weak for long-term retention. Interleaving feels harder but is stronger for long-term memory and transfer. Put it into practice with mixed homework sets, cross-chapter review questions, and tests that include material from previous units.
References:
Rohrer, D., & Taylor, K. (2007). The shuffling of mathematics problems improves learning. Instructional Science, 35(6), 481–498.
Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories. Psychological Science, 19(6), 585–592.
Taylor, K., & Rohrer, D. (2010). The effects of interleaved practice. Applied Cognitive Psychology, 24(6), 837–848.
Disclaimer: This article is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with any questions about a medical condition.
Your Next Steps
- Today: Pick one idea from this article and try it before bed tonight.
- This week: Track your results for 5 days — even a simple notes app works.
- Next 30 days: Review what worked, drop what didn’t, and build your personal system.
Last updated: 2026-03-16
About the Author
Written by the Rational Growth editorial team. Our health and psychology content is informed by peer-reviewed research, clinical guidelines, and real-world experience. We follow strict editorial standards and cite primary sources throughout.