How to study so it sticks

What it covers

1. Retrieval beats rereading Reading your notes again feels productive because the words look familiar. But familiarity is not memory. Pulling an answer out of your head, with the book closed, is what strengthens it. In classic experiments students who read a passage once and then tested themselves recalled far more a week later than students who reread it four times, even though the rereaders felt more confident. The practical rule: after every lesson, close it and write down three things you remember, then check.
2. Space it out Ten minutes a day for six days beats one hour on one day, even though the total time is the same. Memory consolidates between sessions, and each return forces a little forgetting to be reversed, which is exactly what makes the trace durable. The ideal gap grows as you learn: a day, then a few days, then a week or two. Cramming works for tomorrow's test and fails for the exam in June.
3. Mix it up Doing twenty problems of the same type in a row trains you to recognise the type from context, not from the problem. Mixing types (interleaving) feels harder and slower during practice but produces much better results on a mixed test, which is what exams are. The same holds for subjects: a session of maths, then biology, then maths again beats two blocks.
4. Fluency is a trap Smooth lectures, highlighted pages and a tidy summary all feel like understanding. They are often the opposite: the easier something is to take in, the less work your memory does. Good study has "desirable difficulties": generating the answer before it is shown, explaining a concept in your own words, drawing the diagram from memory. If it feels easy, you are probably not learning much.
5. Errors are information Getting a question wrong, then seeing the answer, produces more learning than getting it right the first time, as long as you find out quickly. Trying to answer before you are taught (and failing) also helps the lesson stick. So quizzes are not just for measuring; they are the learning. Keep a list of what you got wrong and come back to it; that list is the most valuable page in your notes.