Editing Spaced repetition (section)

{{Short description|Learning technique performed with flashcards}}
{{Use mdy dates|date=January 2022}}
{{More citations needed|date=February 2020}}
[[File:Leitner system alternative.svg|230px|thumb|In the [[Leitner system]], correctly answered cards are advanced to the next, less frequent box, while incorrectly answered cards return to the first box for more aggressive review and repetition.]]

'''Spaced repetition''' is an [[evidence-based learning]] technique that is usually performed with [[flashcard]]s. Newly introduced and more difficult flashcards are shown more frequently, while older and less difficult flashcards are shown less frequently in order to exploit the psychological [[spacing effect]]. The use of spaced repetition has been proven to increase the rate of learning.<ref>{{cite journal |last1=Smolen |first1=Paul |last2=Zhang |first2=Yili |last3=Byrne |first3=John H. |title=The right time to learn: mechanisms and optimization of spaced learning |journal=Nature Reviews Neuroscience |date=January 25, 2016 |volume=17 |issue=2 |pages=77–88 |doi=10.1038/nrn.2015.18 |pmid=26806627 |pmc=5126970 |arxiv=1606.08370 |bibcode=2016arXiv160608370S }}</ref>

[[File:ForgettingCurve.svg|thumb|Spaced repetition with forgetting curves]]

Although the principle is useful in many contexts, spaced repetition is commonly applied in contexts in which a learner must acquire many items and retain them indefinitely in memory. It is, therefore, well suited for the problem of [[vocabulary]] acquisition in the course of second-language learning. A number of [[#Software|spaced repetition software programs]] have been developed to aid the learning process. It is also possible to perform spaced repetition with physical flashcards using the [[Leitner system]]. The [[testing effect]] and spaced repetition can be combined to improve long-term memory. Therefore, memorization can be easier to do.