Remember those flashcards mom made you cycle through every morning while she drove you to school? Times tables, vocab words. Then she’d start quizzing you on your spelling words. As much as you might hate to admit it, these methods worked. You remembered the information she was trying to pound into your head. But why did it work? The answer: the testing effect.

The testing effect has been given many names over the years—active recall, retrieval practice—but it all refers to the same mechanism: asking your brain to remember and retrieve information on cue. And, as Henry Roediger and Jeffrey Karpicke put it, “Testing has a powerful effect on long-term retention.”

Some might say, “Flashcards are a lot of work. What about just re-reading? That’s got to be as good as testing, right?” Wrong. Re-reading material might make you better at reading the test questions, but making yourself pull the information out of your brain makes you better at answering the questions.

Studies have compared students who prepared for an exam by testing themselves against students who prepared by reading. The result: the pre-testing students received higher scores on the exam than the reading students. Furthermore, the success of testing is linked to timing. The power of the testing effect increases as more time passes between the practice test and the actual exam.

Research has also shown that multiple practice tests can further improve retention and test performance. Repeatedly asking your brain to dig around and produce sought-after information creates stronger connections and retrieval pathways in the brain. In one study, students who repeatedly practiced retrieval (testing) doubled their proportion of correct responses on the final test compared to students who only practiced retrieval once.

So what can we learn from the testing effect? Not only are quizzes the way to go when we want to remember information, but also—at least when it comes to flashcards and spelling quizzes—mom was right.