Spaced repetition
Encyclopedia
Learning
Learning is acquiring new or modifying existing knowledge, behaviors, skills, values, or preferences and may involve synthesizing different types of information. The ability to learn is possessed by humans, animals and some machines. Progress over time tends to follow learning curves.Human learning...
technique that incorporates increasing intervals of time between subsequent review of previously learned material; this exploits the psychological spacing effect
Spacing effect
In psychology, the spacing effect refers to the fact that humans and animals more easily remember or learn items in a list when they are studied a few times over a long period of time , rather than studied repeatedly in a short period time .The phenomenon was first identified by Hermann Ebbinghaus;...
. Alternative names include spaced rehearsal, expanding rehearsal, graduated intervals, repetition spacing, repetition scheduling, spaced retrieval and expanded retrieval.
Although the principle finds use in many contexts, spaced repetition is commonly applied in contexts in which a learner must acquire a large number of items and retain them indefinitely in memory. Hence, it is well suited for the problem of vocabulary
Vocabulary
A person's vocabulary is the set of words within a language that are familiar to that person. A vocabulary usually develops with age, and serves as a useful and fundamental tool for communication and acquiring knowledge...
acquisition in the course of second language learning due to the usually enormous size of a given language's inventory of open-class
Open class (linguistics)
In linguistics, a word class may be either an open class or a closed class. Open classes accept the addition of new morphemes , through such processes as compounding, derivation, inflection, coining, and borrowing; closed classes generally do not....
words.
Research and Applications
The notion that spaced repetition could be used for improving learning was first proposed in the book Psychology of Study by Prof. C. A. MaceCecil Alec Mace
Cecil Alec Mace was a British philosopher and industrial psychologist.He discredited the notion that workers are primarily incentivized by money. He also stated that people have a "will to work." In 1935, he conducted the first empirical studies of goal setting.- Literary works :Sibylla; or, the...
in 1932. In 1939, Spitzer tested the effects of a type of spaced repetition on 6th Graders in Iowa to learn science facts. Spitzer tested over 3600 students in Iowa and showed that spaced repetition was effective. This early work went unnoticed and the field was relatively quiet until the late 1960s when cognitive psychologists, notably including Landuaer & Bjork and Melton, explored manipulation of repetition timing as a means to improve recall. Around the same time, Pimsleur language courses
Pimsleur language learning system
The Pimsleur language learning system is a language acquisition method developed by Paul Pimsleur. The system is based on four main ideas: anticipation, graduated interval recall, core vocabulary, and organic learning. The Pimsleur method is an audio-based system, in which the listener constructs...
pioneered the practical application of spaced repetition theory to language learning and in 1973, Sebastian Leitner
Sebastian Leitner
Sebastian Leitner was a German commentator and science popularizer.As a student in Vienna, he was briefly kept in custody by the Nazis in 1938 because of his opposition against the annexation of Austria into Greater Germany. Later he moved to Frankfurt to study law, but he was recruited by the...
devised his "Leitner system
Leitner system
The Leitner system is a widely used method to efficiently use flashcards that was proposed by the German science journalist Sebastian Leitner in the 1970s...
", an all-purpose spaced repetition learning system based on flashcard
Flashcard
A flashcard or flash card is a set of cards bearing information, as words or numbers, on either or both sides, used in classroom drills or in private study. One writes a question on a card and an answer overleaf. Flashcards can bear vocabulary, historical dates, formulas or any subject matter that...
s.
At the time, spaced repetition learning was principally being implemented via flashcard systems; these systems were somewhat unwieldy since any significant study base requires many thousands of flashcards. With the increase in accessibility of personal computing, spaced repetition began to be implemented with computer-assisted language learning
Computer-assisted language learning
Computer-assisted language learning is succinctly defined in a seminal work by Levy as "the search for and study of applications of the computer in language teaching and learning"...
software-based solutions in the 1980s. The aim of these programs was to tailor the repetition spacing based on learner performance. To enable the user to reach a target level of achievement (e.g. 90% of all material correctly recalled at any given time point), the software adjusts the repetition spacing interval. Material that is hard is shown more often and material that is easy is shown less often, with hard or easy being defined by the ease with which the user is able to produce a correct response.
There are several families of algorithms for scheduling spaced repetition:
- Neural networkNeural networkThe term neural network was traditionally used to refer to a network or circuit of biological neurons. The modern usage of the term often refers to artificial neural networks, which are composed of artificial neurons or nodes...
s based - Leitner systemLeitner systemThe Leitner system is a widely used method to efficiently use flashcards that was proposed by the German science journalist Sebastian Leitner in the 1970s...
: 5 stages and an arbitrary number of stages - SM-family of algorithms (SuperMemoSuperMemoSuperMemo is a learning method and software package developed by SuperMemo World and SuperMemo R&D with Piotr Wozniak in Poland from 1985 to the present...
): SM-0 (a paper implementation) to SM-11 (in SuperMemo 2006)
Some have theorized that the precise length of intervals does not have a great impact on algorithm effectiveness, although it has been suggested by others that the interval (expanded vs. fixed interval, etc.) is quite important; the experimental data regarding this point are mixed.
Pimsleur's graduated-interval recall
Graduated-interval recall is a type of spaced repetition published by Paul PimsleurPaul Pimsleur
Paul Pimsleur was a scholar in the field of applied linguistics.Pimsleur grew up in New York City and earned a bachelor's degree at the City College of New York and a Ph.D...
in 1967. It is used in the Pimsleur language learning system
Pimsleur language learning system
The Pimsleur language learning system is a language acquisition method developed by Paul Pimsleur. The system is based on four main ideas: anticipation, graduated interval recall, core vocabulary, and organic learning. The Pimsleur method is an audio-based system, in which the listener constructs...
and it is particularly suited to programmed audio instruction due to the very short times (measured in seconds or minutes) between the first few repetitions, unlike other forms of spaced repetition which may not require such precise timings.
The intervals published in his paper were: 5 seconds, 25 seconds, 2 minutes, 10 minutes, 1 hour, 5 hours, 1 day, 5 days, 25 days, 4 months, 2 years.
By timing a Pimsleur language program with a stopwatch, it is possible to verify that the intervals are not followed exactly but have upper and lower bounds. A similar principle (graduated intervals with upper and lower bounds) is used in at least one open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
software project (Gradint) to schedule its audio-only lessons.
Prominent researchers
- Hermann EbbinghausHermann EbbinghausHermann Ebbinghaus was a German psychologist who pioneered the experimental study of memory, and is known for his discovery of the forgetting curve and the spacing effect. He was also the first person to describe the learning curve...
- Thomas K. Landauer and Robert A. BjorkRobert A. BjorkRobert Allen Bjork is Distinguished Professor of Psychology at the University of California, Los Angeles. His research focuses on human learning and memory and on the implications of the science of learning for instruction and training...
- Cecil Alec MaceCecil Alec MaceCecil Alec Mace was a British philosopher and industrial psychologist.He discredited the notion that workers are primarily incentivized by money. He also stated that people have a "will to work." In 1935, he conducted the first empirical studies of goal setting.- Literary works :Sibylla; or, the...
Prominent practitioners
- Paul PimsleurPaul PimsleurPaul Pimsleur was a scholar in the field of applied linguistics.Pimsleur grew up in New York City and earned a bachelor's degree at the City College of New York and a Ph.D...
- Sebastian LeitnerSebastian LeitnerSebastian Leitner was a German commentator and science popularizer.As a student in Vienna, he was briefly kept in custody by the Nazis in 1938 because of his opposition against the annexation of Austria into Greater Germany. Later he moved to Frankfurt to study law, but he was recruited by the...
- Piotr WoźniakPiotr Wozniak (researcher)Piotr A. Woźniak is the principal author of SuperMemo and a researcher in the theory of spaced repetition.-Partial bibliography:Academic articles he has authored include:...
Software
Most programs are modeled after the manual style of learning with flashcardFlashcard
A flashcard or flash card is a set of cards bearing information, as words or numbers, on either or both sides, used in classroom drills or in private study. One writes a question on a card and an answer overleaf. Flashcards can bear vocabulary, historical dates, formulas or any subject matter that...
s: items to memorize are entered into the program as question-answer pairs; when a pair is due to be reviewed, the question is displayed on screen, and the user must attempt to remember the answer; when the user has succeeded or failed, the answer is manually revealed, and then tells the program how easily he recalled the answer or failed to. The program schedules pairs based on spaced repetition algorithms.
Without a program the user has to schedule flashcard
Flashcard
A flashcard or flash card is a set of cards bearing information, as words or numbers, on either or both sides, used in classroom drills or in private study. One writes a question on a card and an answer overleaf. Flashcards can bear vocabulary, historical dates, formulas or any subject matter that...
s; this takes time and restricts to simple algorithms like the Leitner system.
Further refinements are found:
- Question/answer can be a sound-file to train the recognition of spoken words.
- Automatic generations of pairs; e.g. for vocabulary it's useful to generate three question-pairs—written foreign word, its pronunciation and its meaning—but data has to be typed only once.
- Show additional information retrieved automatically, like example-sentences containing a word.
- Support advanced input formats such as LaTeXLaTeXLaTeX is a document markup language and document preparation system for the TeX typesetting program. Within the typesetting system, its name is styled as . The term LaTeX refers only to the language in which documents are written, not to the editor used to write those documents. In order to...
. - Using a web platform instead of an installable program.
- Combine spaced repetition with online community functions, e.g. sharing courses.
Some Implementations:
- AnkiAnkiAnki is a spaced repetition flashcard program. The software is similar to SuperMemo, a commercial product for the same purpose, and Mnemosyne, another free flashcard program. Anki is the Japanese word for "memorizing"....
- eSpindle LearningESpindle LearningeSpindle Learning is an online vocabulary and spelling coaching program. It was founded in 2004, and incorporated as a 5013 nonprofit. Membership fees range from $79.80 a year to $599 for a lifetime membership and the organization had 5000 members in 2007.- Features :The program is based on a...
aka LearnThat.org - Flashcard ExchangeFlashcard ExchangeFlashcard Exchange is a free web-based application for the creation, study, and sharing of flashcards. With more than 21 million flashcards generated by its users, Flashcard Exchange's electronic flashcard library is the biggest in the world.-History:...
- MnemosyneMnemosyne (software)Mnemosyne is spaced repetition software developed from 2003 until the present. The software is similar to SuperMemo, commercial software developed by Piotr Wozniak....
- SkritterSkritterSkritter is a tool for learning Chinese and Japanese writing with stroke-level feedback, tone practice, audio playback, definition practice, and progress feedback. Skritter is owned by Ohio-based start-up Inkren....
- SuperMemoSuperMemoSuperMemo is a learning method and software package developed by SuperMemo World and SuperMemo R&D with Piotr Wozniak in Poland from 1985 to the present...
- WinflashWinflashWinFlash Educator is a member of a family of educational software programs developed by Open Window Software known collectively as WinFlash. It is a flashcard program....
- OpenCardsOpenCardsOpenCards is a free spaced repetition flashcard program. The software is similar to SuperMemo, Anki or Mnemosyne.The flashcards are saved as PowerPoint presentation files and may include text, images, sounds and LaTeX equations. The learning states are saved in hidden meta-data files in the same...
The above list is not comprehensive, nor does it intend to be. The list of flashcard software provides a broader overview.
Further reading
- Caple, C. (1996). "The Effects of Spaced Practice and Spaced Review on Recall and Retention Using Computer Assisted Instruction". Dissertation for the degree of Doctor of Education, North Carolina State University.http://www.eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=ED427772&ERICExtSearch_SearchType_0=no&accno=ED427772
- de Boer, V. (2003, August). "Optimal Learning and the Spacing Effect: Theory, Application and Experiments based on the Memory Chain Model". Artificial Intelligence Master's Thesis for Computational Psychology, University of Amsterdam.http://www.neuromod.org/mnemo/victor/thesis
- Dempster, F. N. (1988). "The Spacing Effect: A Case Study in the Failure to Apply the Results of Psychological Research". American Psychologist, 43(8), 627-634.
- Greene R. L. (2008). Repetition and spacing effects. In Roediger H. L. III (Ed.), Learning and memory: A comprehensive reference. Vol. 2: Cognitive psychology of memory (pp. 65–78). Oxford: Elsevier.
- Karpicke, J. D., & Roediger, H. L. (2007). "Expanding Retrieval Practice Promotes Short-Term Retention, but Equally Spaced Retrieval Enhances Long-Term Retention". Journal of Experimental Psychology: Learning, * Memory, and Cognition, 33(4), 704-719.http://psych.wustl.edu/memory/Roddy%20article%20PDF%27s/Karpicke_Roediger_2007_JEPLMC.pdf
- Pavlik, P. I. (2005). The Microeconomics of Learning: Optimizing Paired-Associate Memory. PhD, Carnegie Mellon.