Spaced repetition
One of the most robust findings in learning science is the spacing effect: distributing practice over time produces much better long-term retention than concentrating it into a single session (cramming). A student who studies for one hour on three separate days will retain significantly more than one who studies for three hours the day before a test. Spaced repetition tools like Anki (which schedules cards to be reviewed just as you are about to forget them) operationalise this finding.
Retrieval practice
Another robust finding is the testing effect or retrieval practice effect: attempting to recall information from memory — even before you feel confident you know it — produces substantially better retention than re-reading or re-watching the same material. This runs counter to intuition: re-reading feels like consolidation, but retrieval practice is more effective. Practical applications: close the book and try to recall what you just read, write practice questions for yourself, use flashcards.
Interleaving
Most people practise skills in blocks: complete all type-A problems, then all type-B problems. Research consistently finds that interleaving — mixing problem types within a practice session — produces better long-term performance, even though it feels harder in the moment (and students typically rate interleaved practice as less effective than blocked practice, even when they perform better on tests after it). The difficulty appears to be the mechanism: struggling to identify which approach to use encodes the learning more deeply.
Deliberate practice
Anders Ericsson's research on expert performance found that what distinguishes experts is not raw hours of practice but the quality of practice — specifically, practice that targets weaknesses, operates at the edge of current ability, and incorporates immediate feedback. Playing chess games or performing music pieces does not qualify as deliberate practice; analysing your mistakes and specifically practising what you do poorly does.