Interleave related skills, not random subjects
Mix things you might confuse with each other — not unrelated subjects thrown together.
Key takeaways
- What it is: Mix things you might confuse with each other — not unrelated subjects thrown together.
- Why it works: Interleaving works largely by training discrimination: noticing the subtle cues that say "this is a type-A problem, not type-B." That benefit only exists when the items are similar enough to be confused. Mixing genuinely unrelated material adds task-switching cost without the discrimination payoff.
- Evidence: Backed by randomized trials / meta-analyses.
- Avoid: Interleaving wildly different subjects (French verbs, then calculus, then history dates) and concluding "interleaving does not work" when the real issue is that nothing needed discriminating.
Why it works
Interleaving works largely by training discrimination: noticing the subtle cues that say "this is a type-A problem, not type-B." That benefit only exists when the items are similar enough to be confused. Mixing genuinely unrelated material adds task-switching cost without the discrimination payoff.
How to do it
- 1Pick categories that learners commonly mix up (e.g. different formula types, similar concepts).
- 2Interleave within that confusable family rather than across totally separate domains.
- 3Notice which pairs you keep misclassifying and weight those more heavily.
What the evidence says
RCT / meta-analysisStudies on inductive learning (e.g. classifying painters by style) and on math problem types show interleaving helps most when categories are similar and must be distinguished, supporting the discrimination account of the effect.
Honest caveat: For wholly unrelated tasks the main mechanism (discrimination) does not apply, so benefits are weaker and switching costs can dominate.
Common mistake
Interleaving wildly different subjects (French verbs, then calculus, then history dates) and concluding "interleaving does not work" when the real issue is that nothing needed discriminating.
IX Coach groups your confusable skills together so the mix is doing discrimination work, not just shuffling unrelated tasks.
Practice this with IX Coach →