Effective study methods: why you forget what you've read three times
Rereading feels productive, but little of it sticks. What works instead: active recall and spaced repetition, explained through one student's midterm prep.
Lukas is a first-year medical student in Debrecen, and his first cell biology midterm is next Thursday. Over the weekend he read through the lecture slides twice, highlighted everything that looked important, and by Sunday evening he felt more or less ready. On Monday, on the bus, he tried to walk through the steps of cellular respiration in his head and got stuck on the second one. He'd known it on Saturday.
That isn't laziness, and it isn't a bad memory. Rereading just doesn't do what most of us use it for. In this post we look at what to do instead: the two effective study methods with the most research behind them, and how to fit them into an ordinary semester.
Why rereading fools you
The second time you read a page, you move faster, the sentences feel familiar, and your brain takes that as a sign that you understand and remember the material. But recognising something and recalling it are two different skills. In the exam nobody asks you to nod along to a familiar sentence. You have to produce the answer on a blank page.
In 2013, John Dunlosky and his colleagues published a long review that rated ten common study techniques based on the experiments done so far. Rereading, highlighting and writing summaries came out fairly weak. The two best ratings went to something else: students testing themselves, and spreading their study over several sessions with gaps in between. These usually go by the names active recall and spaced repetition.
You still need to read, of course. There's no other way to understand the material the first time. The trouble starts when the second and third pass are also just reading.
How fast do we forget?
In the late 19th century the German psychologist Hermann Ebbinghaus ran memory experiments on himself. He learned lists of nonsense syllables and then measured how much of them he still knew after hours, days and weeks. The forgetting curve he drew from the results has been in psychology textbooks ever since: most of what you've just learned slips away in the first day or two, and after that forgetting slows down.
The curve can be bent, though. Every time you manage to pull something out of memory, you forget it more slowly the next time. That's why it matters how and when you review.
Active recall: test yourself
Active recall simply means closing your notes and trying to bring back what you want to know from memory. It isn't glamorous, and at first it's uncomfortable, because it shows you exactly what you don't know yet.
One of the most cited experiments on this was published by Jeffrey Karpicke and Henry Roediger in Science in 2008. University students had to learn Swahili–English word pairs. The ones who kept testing themselves while studying remembered far more words a week later than the ones who spent the same time restudying. Interestingly, while they were studying, both groups felt about equally confident.
For Lukas, this would mean that after each lecture he doesn't flip through the slides again. Instead he writes down everything he can remember about cellular respiration on a blank sheet, and only then compares it with his notes. Whatever he missed, he looks up, and two days later he tries again. Flashcards work the same way (a question on one side, the answer on the other), and so does a short practice quiz, or explaining the topic to a classmate. What they have in common is that the answer has to come from your head, not from the page.
One small but important rule for flashcards: say the answer before you flip the card. If you flip first, you're back to recognising instead of recalling.
Spaced repetition: the same hours, spread out better
Spaced repetition means reviewing the same material in several shorter sessions with growing gaps between them, rather than in one long sitting. The next day, say, then three days later, then a week later.
If Lukas spends three hours on cell biology the night before the midterm, he'll probably remember a fair amount on Thursday. For the end-of-semester exam, though, he'll be starting almost from scratch. If he spreads the same three hours over two weeks, twenty or thirty minutes a day, he's ready for the midterm and doesn't start from zero in exam season either.
People used to do this with a Leitner box: a card you knew moved to a compartment further back that you checked less often, and a card you got wrong went back to the front. Today apps do the scheduling for you. Whichever you use, two things decide whether it works. Start early, because the method pays off over weeks, and the night before the exam there's nothing left to spread out. And be honest with yourself: if you hesitated on a card, don't mark it as easy.
When to start, and how much each day
The simplest setup combines the two: you learn from flashcards and review them on a schedule. That way you get both the recall and the timing.
If your midterms are just starting, it isn't too late. After each lecture, write down the key terms, and from then on go through the cards that are due each day. That's ten minutes at first and more later. If the daily pile grows too big, take on less new material for a few days until you catch up.
If you're already planning for exam season and need to juggle several subjects, our page on preparing for university exams walks through a detailed week-by-week example. And if you're studying in Hungary in a language that isn't your first, have a look at our page for international students.
Where KognitiMind fits in
To be honest, you don't need an app for any of this. Paper, a pen and a bit of persistence are enough. We built KognitiMind because we kept seeing students give up not at the recall stage but before it, when they'd have to write flashcards by hand for a whole semester's worth of slides.
You upload your notes: a PDF, a Word file, lecture slides, or on a paid plan even a photo of a handwritten page. From that we make flashcards and a practice quiz, and we hand the cards back to you on a review schedule. For each card you mark how well it went and see how many days it will be until it comes back. If something doesn't make sense, you can ask about it in the document chat, and we show you which page or slide the answer comes from. You can also ask for a summary, but use it as a map rather than as study material (we covered why at the start). The cards, quizzes and summaries are generated in the language you choose, English or Hungarian, whatever language the original document is in. If you prefer reviewing in Anki, you can export the cards there too. The features page has everything in one place.
The one thing we can't do for you is the recalling itself. And the AI can make mistakes, so if a card looks off, check it against your original notes. You can see exactly how it goes from upload to first review on the How it works page, and the plans are on the pricing page.
Frequently asked questions
What is the most effective study method?
There's no single magic method, but based on the research, active recall and spaced repetition have the strongest evidence behind them, and they work best together.
Is highlighting bad?
It isn't bad, just not enough. It helps you find the important parts. You'll only remember them, though, if you later bring them back from memory.
How long before the exam should I start?
As soon as you've understood a section. Even two or three weeks make a big difference, but the earlier you start, the less time you need each day.
Does this work for midterms too, or only finals?
Both. In fact, midterm season is the best time to start. Whatever you put on cards then and review regularly won't be new material when finals come around.
More questions are answered in our FAQ. If you'd like to try it on your own notes, sign up for free. No card needed.