Active Recall and Spaced Repetition: How to Remember What You Study
UPDATED · 7 MIN READ
If you only change two things about how you study, make it these. Active recall and spaced repetition are the two best-supported techniques in learning research, and they work best together: recall is what you do in a session, spacing is when you do it.
What is active recall?
Active recall means retrieving information from memory instead of looking at it again. Answering a question, covering your notes and writing out what you remember, or turning a flashcard over are all active recall.
Each successful retrieval makes the memory easier to find next time. Research on the testing effect shows that practising retrieval leads to better long-term retention than spending the same time re-reading — even when you get some answers wrong, as long as you check them.
What is spaced repetition?
Memories fade quickly after you first learn something — the forgetting curve described by Hermann Ebbinghaus in the 1880s. Reviewing material just as you are starting to forget resets that curve and makes it slower each time.
Spaced repetition means scheduling reviews at increasing intervals instead of all at once. The same total study time, spread out, leads to much better retention than a single long session.
A simple spaced repetition schedule
If you got something wrong, shorten the next gap for that item; if it was easy, lengthen it. Flashcard apps automate this, but a paper schedule works too.
- Day 0: learn the topic, then test yourself at the end of the session.
- Day 1: review with active recall.
- Day 3: review again.
- Day 7: review again.
- Day 14–21: review again, then before the exam.
Ways to practise active recall
- Flashcards: a question or term on the front, the answer on the back.
- Practice questions and past papers.
- Blurting: write down everything you remember about a topic, then check what you missed.
- Teaching: explain the topic out loud as if to a friend.
- Mind maps drawn from memory, then compared with your notes.
Skip the hours of making flashcards
Writing good cards takes time that could go into reviewing them. You can generate flashcards, a practice quiz and a summary straight from your own notes or a PDF, then spend your time on the part that builds memory: recalling.
Make reviews a daily habit
Spaced repetition only works if the reviews actually happen. A short daily review block — even 15 minutes — is enough to keep up. Put it at the start of each study session.
Frequently asked questions
Is active recall better than re-reading?
Yes. Studies comparing the two consistently find that practising retrieval produces better long-term memory than re-reading for the same amount of time.
How often should I review with spaced repetition?
A common starting schedule is one day, three days, one week and two to three weeks after learning, adjusting gaps shorter for items you miss and longer for items you know well.
Can I use active recall for subjects like math?
Yes. For problem-based subjects, active recall means solving problems without looking at worked examples first, and mixing problem types so you practise choosing the method.