Interleave different topics during study or work

Mix related but distinct material rather than blocking all of one topic before moving to the next.

Why it works

Blocked practice (all of topic A, then all of topic B) feels more fluent but produces weaker learning because the brain never has to reconstruct the retrieval route — it's already warm. Interleaving forces the brain to retrieve from scratch on each switch, which strengthens the memory trace and also requires the brain to compare categories — building the discrimination skills that transfer to novel problems.

How to do it

1. When studying or preparing on related topics, mix them in the same session rather than completing one fully.
2. After 10–15 minutes on topic A, shift to topic B, then return to A.
3. Accept that the session will feel harder and less "productive" — this is the learning signal.

Evidence

Interleaved practice reliably outperforms blocked practice on delayed retention tests across mathematics, motor learning, and perceptual learning domains, despite feeling less effective during acquisition. (rct)

Effects are strongest for discrimination and retention; for early acquisition of entirely new skills, some blocking may be needed before interleaving is productive.

Sources

• Rohrer & Taylor (2007), interleaving mathematics practice, European Journal of Cognitive Psychology
• Kornell & Bjork (2008), interleaved inductive learning, Psychological Science

Common mistake

Abandoning interleaving because it "feels like it's not working" — the metacognitive sense that blocked practice is better is a documented and consistent illusion.