Spaced repetition and retrieval practice: how to actually remember what you study

Absorbing what I studied was one of the reasons I went looking for help and, eventually, an ADHD evaluation. When I started reading the research on learning, two ideas came up again and again: retrieval practice and spaced repetition. This article explains both, what the studies found, and how to use them. For the bigger picture, including sleep, breaks and exercise, start with my guide to improving memory and focus.

What is retrieval practice?

Retrieval practice is any activity that makes you pull information out of your memory. Flashcards, practice questions, a blank page where you write everything you remember, or explaining a topic out loud without notes all count.

The best-known experiment comes from Roediger and Karpicke. Students read short texts and then either restudied them or took recall tests. On a test five minutes later, restudying gave slightly better results. On tests two days and one week later, the students who had practiced recall remembered substantially more (Psychological Science, 2006).

The lesson: the effort of remembering is part of what makes memory last.

What is spaced repetition?

Spaced repetition, also called distributed practice, means reviewing material across several sessions with gaps in between, instead of in one long block.

Cepeda and colleagues combined the results of 317 experiments, covering 839 assessments, in a meta-analysis on spacing. Spreading practice out improved retention, and the best gap between reviews grew as the time you needed to remember the material grew (Psychological Bulletin, 2006). In plain words: for a quiz next week, review a few days apart. For something you need months from now, the gaps can be longer.

Why does rereading feel like it works when it does not?

When you reread, the text feels familiar, and familiarity feels like knowing. In the Roediger and Karpicke study, the students who restudied were more confident about their memory, yet they remembered less on the delayed tests.

The large review by Dunlosky and colleagues rated rereading, highlighting and summarization as low utility, and practice testing and distributed practice as high utility (Psychological Science in the Public Interest, 2013). That does not mean you should never highlight. It means highlighting is a starting point, not the learning itself.

How do I use retrieval practice when I study?

• Flashcards with a real question. Write a question on one side and the answer on the other. Say or write your answer before you flip the card.
• The blank page. After reading a chapter, close the book and write everything you remember. Then open the book and check what you missed.
• Practice questions. Use end-of-chapter questions, old exams, or questions you write yourself.
• Teach it. Explain the idea out loud, as if to a friend, without looking at your notes.

Getting answers wrong is part of the process. Check the correct answer right away and come back to that item in your next review.

How far apart should I space my reviews?

Research shows that the best gap depends on how long you need to remember the material, so there is no single perfect schedule. The plan below is a practical starting point, not a formula from a specific study. Adjust it to your exam date or goal.

Many flashcard apps schedule reviews for you, and paper cards in a few boxes work too. The method matters more than the tool.

What about other study techniques, like interleaving or self-explanation?

Dunlosky and colleagues rated three more techniques as moderate utility: elaborative interrogation, self-explanation and interleaved practice (Psychological Science in the Public Interest, 2013). Moderate means they showed promise, but with less evidence or a narrower range of uses than testing and spacing.

• Elaborative interrogation: asking yourself why a fact is true, and answering it.
• Self-explanation: explaining how a new idea connects to what you already know, or explaining each step while solving a problem.
• Interleaved practice: mixing different kinds of problems in one session, instead of doing all of one kind and then all of another.

These pair well with retrieval practice. For example, when a flashcard asks “what”, add a second question that asks “why”.

What does a study session with these methods look like?

Here is one way to organize a single session. It is a template, not a rule, so change the timing to fit your day.

1. Warm up with recall. Before opening anything, write down what you remember from your last session.
2. Check and fix. Open your notes and correct what you missed or got wrong.
3. Learn new material. Read or watch with one goal: to be able to explain it afterward without looking.
4. Close everything and test yourself. Use flashcards, practice questions or the blank-page method.
5. Plan the next review. Put the next recall round on your calendar a day or a few days later.

Short breaks between steps help, as I explain in the section on breaks of my main guide.

Does this work for people with ADHD?

The studies above tested general groups of students. They were not designed specifically for people with ADHD, so I cannot tell you they will work the same way for you.

What I can say is that these techniques are flexible. Recall rounds can be short, and spacing can be built into a calendar or an app so you do not have to remember to review. A clinician, therapist or ADHD coach can help you adapt study strategies to your needs. Study habits support professional care; they do not replace it. You can read more about ADHD from the National Institute of Mental Health.

How can I use this at work, not just at school?

• New software or processes: after a training, close the slides and write the key steps from memory.
• Product or client knowledge: turn facts you keep looking up into a short set of flashcards.
• Meetings: right after a meeting, write the three main decisions without looking at your notes.
• Languages and certifications: these are a natural fit for spaced flashcards.

And remember the foundation: memory needs sleep. See how sleep affects memory and focus.

About the author: Amanda Abreu

I was diagnosed with ADHD three years ago, after I went to a neuropsychologist to understand why I could not keep my concentration while studying or absorb what I was learning. Since then I have been reading the research on memory and focus and writing it up here in plain language, with every source linked.

I am not a doctor or a health professional. This guide is general education, not medical advice. Read my story or email me.

Medical note: this article is for general information and does not replace advice from your doctor. If you have concerns about your memory, attention or sleep, talk to a qualified health professional. See our medical disclaimer. This page contains no affiliate links.