Spaced repetition

Spaced repetition is a learning technique in which increasing intervals of time are used between subsequent reviews. Alternative names include expanding rehearsal, graduated intervals, repetition spacing, repetition scheduling, spaced retrieval and expanded retrieval.

Applications

Practical applications of spaced repetition were first suggested in the book Psychology of Study by Prof. C. A. Mace in 1932.

Pimsleur language courses use spaced repetition techniques, and in the 1970s Sebastian Leitner devised his Leitner system, an all-purpose system based on flashcards.

More recently, spaced repetition has also been implemented into computer-assisted language learning software to gradually adapt the optimum spacing of repetitions to individual needs. A typical optimization criterion used in spaced repetition is the requested level of knowledge retention, i.e. percent of knowledge that is to be remembered.

There are several families of algorithms for scheduling spaced repetition:

• Neural networks based
• Sebastian Leitner system learning machines:
  • 5 stages
  • n stages
• SM-family of algorithms (SuperMemo):
  • SM-0
  • SM-2
  • SM-4
  • SM-5
  • SM-6
  • SM-8
  • SM-11

Prominent researchers

• Cecil Alec Mace
• Hermann Ebbinghaus
• Sebastian Leitner

Software

• SuperMemo
• Mnemosyne (spaced repetition software)

See also

• Study Software
• Testing effect
• Spacing effect

Computer software using spaced repetition

The discussions tab for this page contain an informative list of products based around spaced repetition. This list is useful for those who want to find such software to use themselves and for those who are interested in seeing what the current state of play in this field is. Unfortunately this list has been deleted from the main article page by an editor on the grounds that it contravenes Wikipedia policy on maintaining long lists of links to external sites and products. Whether this list is inappropriate is open to discussion and just removing it without at least providing a link to where an equally useful list can be found seems unhelpful. If a better list is available elsewhere then please link to it otherwise the removal of information that is not easily available elsewhere and is certainly useful and/or of interest to many readers of this page is not constructive.