# Spaced Repetition Space Repetition is a learning and memorization technique based on the [[Spacing effect]], that aims to fight against the [[Forgetting curve]]. The main idea is that active recall with increasing time intervals reduces the probability of forgetting information. Newly introduced or difficult material thus needs to be reviewed more frequently, while older or easier material needs to be reviewed less often. Here's a visualization of the effect of spaced repetition on the [[Forgetting curve]]: ![[Spaced repetition - Effect on the forgetting curve.png]] Spaced repetition was conceived in the 1880s by [[Hermann Ebbinghaus]], a German psychologist. Spaced Repetition is valuable for almost everyone, not just students. It's all about retaining, and applying what you have learned. ## In practice... In practice, the goal is to revisit the material at increasing intervals to increase retention. So, we must review the right information at the right time. One popular approach is to use flashcards (physical or digital) with knowledge and questions to assess it. Using digital flash cards is interesting, because specialized software (e.g., Anki, SuperMemo, Memrise) can help us centralize those and manage the whole process for us, presenting us the right information at the right times. Correct answers, leading to longer intervals before the next review, while incorrect answers imply earlier reviews. ![[Spaced repetition - in practice.png]] Many rely on the [[Leitner system]], which can also be implemented using paper flashcards. ## Intervals After learning something new, the first review/repetition should be done within hours or a day. Further reviews are spaced out further and further. For example, the intervals could be: - 1 day, 3 days (day 4), 7 days (day 11), 14 days (day 25), ... - 1 day, 1 day (day 2), 2 days (day 4), 4 days (day 8), 7 days (day 15), 15 days (day 30) There are no hard and fast rules, but intervals should be set in function of the target. If you want to retain something by date X, then work backwards from there. If you want to retain something forever, then just increase the intervals each time you succeed (cfr [[Leitner system]]), etc. Many spaced repetition applications (e.g., Anki, RemNote, etc) use algorithms to determine the optimal review intervals for each piece of information. ## Related - [[Forgetting curve]] - [[Spacing effect]] - [[Learning curve]] - [[Leitner system]] ## References - https://en.wikipedia.org/wiki/Spaced_repetition - https://www.khanacademy.org/science/learn-to-learn/x141050afa14cfed3:learn-to-learn/x141050afa14cfed3:spaced-repetition/a/l2l-spaced-repetition - https://www.kpu.ca/sites/default/files/Learning%20Centres/Think_SpacedRepetition_LA.pdf - https://collegeinfogeek.com/spaced-repetition-memory-technique - https://help.remnote.com/en/articles/9337171-understanding-spaced-repetition