Space it out
Short reviews spread over days beat one long cram.
PsychologyHow to studyAbout 3 min: 2 reading, 1 practiceUpdated
Educational, not medical or mental-health advice.
- Explain the spacing effect
- Build a review schedule with growing gaps
- Combine spacing with self-testing
How to study: lesson 2 of 5
- How to study
- Test yourself instead of rereading 3 min
- Space it out 3 min
- Mix your practice 3 min
- Focus in short sessions 3 min
- Make a study plan you will keep 4 min
Try first
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Pairs with OpenStax, Psychology 2e, chapter 8 (Memory), section 8.4 "Ways to Enhance Memory"; Dunlosky et al. (2013)
What it is
Spacing means reviewing the same material several times with gaps in between, rather than all in one sitting. Two hours spread over four days beats the same two hours the night before.
Memory fades fast after you first learn something. Hermann Ebbinghaus showed this curve of forgetting in the 1880s by testing himself on lists of nonsense syllables. Each review, done just as things start to slip, slows the fading down.
Quick check
Tap an answer to check it.
Same 2 hours of study. Which plan helps you remember longest?
- That is cramming: it fades fast
Show answer
30 minutes on four different days. Spreading reviews over days slows forgetting.
Why it matters
Cramming can get you through tomorrow morning, but much of it fades within weeks without review. A large review of more than 300 experiments (Cepeda and colleagues, 2006) found that spaced study beat massed study again and again, and that longer gaps suit material you need to keep for longer.
Worked example
A simple schedule for one lesson, using its quiz as your review:
| When | What |
|---|---|
| Day 1 | Learn the lesson, do the quiz |
| Day 2 | Quiz again from memory |
| Day 4 | Quiz again |
| Day 8 | Quiz again |
| Day 16 | Quiz again |
Each gap roughly doubles. It's a rule of thumb, not a tested optimum. If you miss something, shorten the next gap for that item. Flashcard apps such as Anki do this scheduling for you.
An illustration of the pattern Ebbinghaus described, not measured data.
Text description
An illustration, not real data: how much you remember over 14 days. Without reviews, memory drops steeply and keeps falling. With reviews on days 1, 3, 7, each review brings memory back up and it falls more slowly afterwards.
Common mistake
Spacing by rereading. The gaps help most when each review is a test (see the lesson before this one). Spaced rereading is better than cramming, but spaced self-testing is better still.
Key terms
- spacing effect
- learning lasts longer when reviews are spread out over time
- forgetting curve
- how quickly memory fades after learning, first measured by Ebbinghaus
- cramming
- studying everything in one long session just before a test
Practise the key terms
Tap a card to turn it over. 3 cards.
| Front | Back |
|---|---|
| spacing effect | learning lasts longer when reviews are spread out over time |
| forgetting curve | how quickly memory fades after learning, first measured by Ebbinghaus |
| cramming | studying everything in one long session just before a test |
Practice
Quick quiz
Tap an answer to check it.
You have 2 hours to learn ten new words before a test in a week. Which plan is best?
- Cramming: it fades within weeks
- One session with no review: most is forgotten by the test
Show answer
30 minutes on four different days. Spreading the same time over several days leads to better long-term memory.
Who first measured how quickly we forget?
- Pavlov studied conditioning in dogs
- Freud did not measure forgetting experimentally
Show answer
Hermann Ebbinghaus. He tested his own memory in the 1880s.
In short
- Memory fades fast after first learning; each spaced review slows the fade.
- Spaced study beats cramming across hundreds of experiments (Cepeda et al., 2006).
- Space your reviews out. A simple schedule is day 1, 2, 4, 8, 16. It's a rule of thumb, not a tested optimum.
- Make each review a self-test, not a reread.
Mastery check
Answer without looking back. Score 80% or more and the lesson is marked done. Your result is kept only in this browser.
Check yourself
Answer in your head first, then open the answer. Nothing is saved.
What is the spacing effect?
Show answer
Learning lasts longer when reviews are spread out over time instead of crammed into one session.
In the example schedule, roughly what happens to the gap between reviews?
Show answer
It roughly doubles each time.
What makes a spaced review work even better?
Show answer
Making each review a self-test rather than a reread.
Further reading
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.
- Ebbinghaus, H. (1885). Über das Gedächtnis (English translation: Memory: A Contribution to Experimental Psychology, 1913).
- Dunlosky et al. (2013), as in the lesson before.
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