Retrieval practice and spacing: two study methods with strong support

Two of the best-supported ideas in the science of learning are simple to describe and surprisingly under-used.

Retrieval practice, sometimes called the testing effect, is the finding that recalling information from memory, by self-quizzing or low-stakes tests, strengthens learning more than simply re-reading it. Re-reading feels productive because the material seems familiar, but familiarity is not the same as being able to recall it.

Spaced repetition is the practice of reviewing material at increasing intervals over time, rather than cramming in one session. Spreading study out generally produces longer-lasting memory than the same time spent in a block.

What the evidence suggests: both methods help across a range of subjects and ages, though the size of the benefit varies, and learners often misjudge which methods work best for them.

Limits: they are techniques for remembering and applying knowledge; they do not replace understanding or motivation. Time and effort are still required, and the experience of retrieval can feel harder than re-reading, which is part of why it works.

Practical use: after a lesson, close the book and write down what you remember, then check, and repeat a few days later.