Why something this crude works
Because it is pure retrieval, with no cues. A flashcard gives you a prompt. A past paper gives you a question. A blank page gives you nothing at all, which makes it the hardest and therefore the most productive form of retrieval practice there is.
It also does something almost no other technique does: it shows you what you did not know you did not know. A flashcard can only ask about a card you made. A blank page reveals the entire section you forgot existed — and the topic you forgot existed is the one that will end your exam.
How to do it properly
- Study a topic. Read it, watch the lecture, whatever. Once.
- Close everything. Genuinely everything. The tab counts.
- Write for ten minutes. Everything you can dredge up. Bullet points, diagrams, half-remembered fragments. Do not stop to check anything.
- Keep going past the point of comfort. The last thirty seconds, when you are convinced you have nothing left, is where the effortful retrieval happens — and effortful retrieval is what strengthens memory.
- Now open the source and mark the gaps in red. The red is the whole output.
- Study only the red. Then blurt again tomorrow.
The mistake everybody makes
Peeking. You stall after four minutes, you feel stupid, you open the notes "just to get going again", and you have converted an active recall exercise into a re-reading exercise with extra steps. The stall is not a failure state. The stall is where the entire benefit lives.