Testing yourself teaches more than rereading

Picture two ways to prepare for an exam. One: reread your notes four times. The other: read them once, then close the notebook and try to recall everything, even if you get it wrong. The second wins by a landslide.

It's called the testing effect, demonstrated by psychologists Roediger and Karpicke: students who quizzed themselves remembered up to twice as much a week later as those who only reviewed, even though the reviewers felt more confident while studying.

The key is effort. Every time you pull something from memory unaided, you strengthen the path back to it. Rereading, by contrast, gives you a false sense of mastery: you recognise the text, but recognising isn't remembering.

So close the book before you're sure you know it. Cover the answers, quiz yourself, get things wrong. That discomfort of searching your memory is, quite literally, learning happening.