History of SuperMemo

1885 - Forgetting curve: German psychologist Hermann Ebbinghaus, the pioneer of experimental study of memory, published his Contribution to Experimental Psychology. He used himself as his sole experimental subject. His work might be considered the first step to SuperMemo (formulated exactly 100 years later). Ebbinghaus' work was very influential (English translation 1913), yet for years it was not followed by similar research of major significance! A myth that can be tracked down to this History of SuperMemo page says that Ebbinghaus invented spaced repetition! Another myth says that Ebbinghaus was first to measure the exponential forgetting curve. The formulas ascribed to Ebbinghaus come from SuperMemo! His was a negative power curve as used for heterogeneous material in newer SuperMemos
1901 - Spaced review: American psychologist William James suggested that review of the learning material should be spaced in time. Similar conclusions were drawn by Ebbinghaus and Jost. This expanding rehearsal idea gave birth to SuperMemo in 1985
1913 - Spacing effect: W. H. Pyle confirmed the superiority of spaced review experimentally in a classroom setting
1932 - Psychology of study: C. A. Mace hinted on the efficient learning methods in his book "The psychology of study". He mentioned "active rehearsal" and "repetitive revisions" that should be spaced in gradually increasing intervals, roughly "intervals of one day, two days, four days, eight days, and so on". This proposition was later taken on by other authors (including Tony Buzan), but did not permeate into the practice of study. Only a computer implementation of the idea, SuperMemo 1.0, half a century later, opened a way for a wider public to benefit from spaced repetition
1969 - Strength Paradox: Robert Bjork noticed a reverse relationship between the probability of recall and the memory effect of a review. This lead to Bjork's theory of disuse (1992) that would distinguish between the storage strength and the retrieval strength. The existence of those two memory variables was independently proven in 1988 by Wozniak on the basis of the properties of memory underlying the concept of SuperMemo (published in 1995), and the precise relationship between the two variables was computed with the help of data obtained from SuperMemo in 2005
1972 - Expanding rehearsal: Sebastian Leitner published "So lernt man lernen" in which he described his Leitner cardbox. The Leitner cardfile technique can be considered a precursor of spaced repetition. Although the timing of repetition in Leitner box is only loosely related to retention levels and is highly affected by the intensity of learning, the technique points to the benefits of the expanding rehearsal in which successive repetitions occur in increasing intervals. The Leitner system appears ineffective in cases when it produces intervals substantially different than those that result in the desired level of knowledge retention; however, it appeared very popular in dozens of flashcard programs
1982 - Active recall: Piotr Wozniak, a student of molecular biology at the Adam Mickiewicz University of Poznan, Poland, became frustrated with his learning progress. Wozniak embarked on a self-study course which would ultimately lead to the development of SuperMemo. He started with an obvious conclusion that active recall serves memory far better than passive review. As a result, Wozniak started writing down all his mission-critical knowledge on paper in a flashcard form
1984 - Minimum information: Wozniak concluded that learning proceeded much faster if knowledge was split into a number of simple questions and answers reviewed independently. This conclusion was later formulated as the minimum information principle, which is now considered part of the definition of the SuperMemo method
1985 - Spaced repetition: Unaware of the previous work in the field, yet using experimental methods first applied by Ebbinghaus a century before, Wozniak designed two simple experiments on his own memory and found how review intervals influence recall. He formulated first spaced repetition algorithm that would later be known as SuperMemo. His learning with the new method started on August 25, 1985. This day marks the birth of computational spaced repetition, i.e. the technique in which knowledge is reviewed in optimum intervals that are determined by a computer with the goal of reaching a desired level of knowledge retention. For a detailed description of the first algorithm see: Using SuperMemo without a computer
1987 - Spaced repetition software: Wozniak, now a student of computer science at the University of Technology in Poznan, wrote his first computer program employing spaced repetition. In 16 evenings, he came up with a very simple SuperMemo 1.0 for MS DOS (written in Borland's Turbo Pascal 3). The first computer algorithm introduced the concept of E-factor (i.e. the number that makes it possible to differentiate between items of different difficulty). Wozniak begun repetitions with SuperMemo 1.0 using his human biology learning material on December 13, 1987. Wozniak's spaced repetition algorithm, opened to the public, was later used by dozens of popular learning applications such as Mnemosyne, Anki, and others. This is how SuperMemo 1.0 looked like:

1988

SuperMemo gradually gained popularity at Adam Mickiewicz University of Poznan, and the University of Technology in Poznan, Poland
SuperMemo 2.0 was written during summer vacation (Turbo Pascal 4.0)
Tomasz Kuehn from University of Technology in Poznan wrote SuperMemo for Atari ST (Pascal)
Przemyslaw Glowacki from University of Technology in Poznan wrote SuperMemo for Atari XL (Basic)
SuperMemo 3.0 was completed in October 1988. It used an up-to-date DOS interface with pull-down menus
in an article that would make part of his Master's Thesis, Wozniak demonstrated the existence of the two components of long-term memory. The terms retrievability and stability were proposed (analogous to retrieval strength and storage strength in Bjork's new theory of disuse). The two variables of memory would underlie future Algorithm SM-17 (2016)

1989

Tomasz Kuehn made the first attempt to commercially sell SuperMemo. His advertisement in Polish computer journal Komputer (later PC World Komputer) sold 10 copies of SuperMemo 2.0.
SuperMemo 4.0 was completed in February with the learning algorithm based on computing the matrix of optimum intervals
SuperMemo 5.0 in October made another step ahead in improving the learning method. It used an algorithm based on computing the matrix of optimal factors

1990

Under the supervision of Prof. Zbigniew Kierzkowski, the Head of the Computer Science Department, Piotr Wozniak wrote his Master's Thesis: Optimization of learning. A new approach and computer application. This 200-pages dissertation was entirely devoted to theoretical aspects of SuperMemo, described the evolution of the learning algorithm, included the model of intermittent learning, and presented the author's optimistic vision of future applications

1991 - SuperMemo entered the commercial arena:

July 5, a commercial company, SuperMemo World, was formed by Piotr Wozniak and his friend and fellow graduate Krzysztof Biedalak. The real capital: one 80286 personal computer
SuperMemo 2 was released as freeware
SuperMemo 6.0 was completed with the learning algorithm based on the approximation of forgetting curves
September, Dr Janusz Murakowski joined SuperMemo World
November, SuperMemo 6 became a finalist of Software for Europe 1992 Award Competition

SuperMemo as the finalist of Software for Europe

1992

January, Marczello Georgiew and Tomasz Kuehn join SuperMemo World
February, Andrzej Horodenski from Computer World initiated commercial sales of SuperMemo 6 by writing the first ever article about the SuperMemo method and software
March, SuperMemo World displayed its products at CeBIT 1992
September, SuperMemo 6 received the first degree award at Softarg 1992, Katowice, Poland
September, SuperMemo 6 received a special award of the Polish Computer Science Society
December, SuperMemo World turned its first quarterly profit
December, SuperMemo 6 was awarded in Product of the Year 1992 competition organized by PC Kurier, Poland

1993

January, after long months of programming, SuperMemo 7.0 was released. It was one of few Windows software products in Poland at that time
March, SuperMemo 5 was released as freeware
March, German Chancellor Helmut Kohl came to the stand of SuperMemo World during CeBIT 1993

Helmut Kohl inspecting SuperMemo
In the picture: Krzysztof Biedalak explains the principles of SuperMemo to Chancellor Kohl

May, SuperMemo 7.2 Audio Visual for Windows was released. This was the first SuperMemo able to play sounds and display pictures
August, written by Krzysztof Wojcieszek, SuperMemo 1.0 for Amiga was released
September, SuperMemo topped charts of best Polish software applications for Amiga (Amiga Magazine)
September, SuperMemo 7 was awarded at Softarg 1993, Katowice, Poland
December, SuperMemo became the first ever Polish software reviewed in Byte International
December, SuperMemo 7 was awarded in Product of the Year 1993, PC Kurier, Poland

1994

January, SuperMemo was voted 4-th most popular Polish software by readers of Polish PC World (behind anti-virus and word-processing products)
March, SuperMemo for Amiga was voted the Product of the Year 1993 among Polish software for Amiga by readers of Amiga Magazine
March, SuperMemo World displayed SuperMemo 7.3 at CeBIT 1993
March, SuperMemo was awarded for the best value/price ratio by the CENA/VYKON journal, Czech Republic
May, SuperMemo 7 was awarded a prestigious Gold Medal at Infosystem Computer Fair in Poznan
July, 10,000-th copy of SuperMemo was sold
August, SuperMemo USA, Inc. publishes SuperMemo 7.4 on CD-ROM, including the audio version of Advanced English best-seller. This title became the first ever Polish Windows software title released on CD-ROM
September, SuperMemo World was granted the special award of the fair's president, and received a free display at Softarg 1995
September, SuperMemo World signed its first OEM bundling deal with JTT, the second largest computer-maker in Poland
October, SuperMemo World published the European release of SuperMemo on CD-ROM
October, SuperMemo 7.2 topped the ranks of best-selling software sold on illegal software market, ahead of Microsoft Word 6.0 and Microsoft Works 3.0 (PC World Komputer, Vol. 11, 1994)
December, SuperMemo for Windows received the Reader's Choice distinction from PC World Komputer (Vol. 12, 1994) by being voted second most popular Polish software in Poland and the most popular Polish Windows software in Poland
December, Wozniak completed his Economics of learning. This doctoral dissertation was entirely devoted to the SuperMemo method and outlined the theoretical basis for future SuperMemos. The concept of Knowledge Machine was an inspiration for Incremental Learning

1995

January, SuperMemo 6 for DOS was released as freeware
February, SuperMemo received a positive review in the most prestigious European computer journal: German Chip
March, SuperMemo 1.0 for Macintosh was released (this version was later discontinued due to poor profitability)
March, SuperMemo World displayed its Multilingual SuperMemo 7.5 CD-ROM at CeBIT 1995
April, Polish Prime Minister Waldemar Pawlak bought a copy of SuperMemo for personal use (he refused a free gift)
April, SuperMemo User Survey revealed that users of SuperMemo consider the program their single most important application!
April, SuperMemo World signed a comprehensive OEM deal with Optimus, the greatest computer-maker in Poland
May, 30,000-th copy of SuperMemo was sold
September, 500 beta-testers received Pre-Release CD-ROM with the first hypermedia SuperMemo codenamed Genius: precursor of SuperMemo 8.0
November, SuperMemo World became the first Polish company ever to display its products at Comdex in Las Vegas (in the picture: Marczello Georgiew)

1996

January, SuperMemo was voted the best Polish application by readers of PC World, Komputer
January, first SuperMemo hypermedia CD-ROM title was released: Video English (with Genius 1.0, early precursor of SuperMemo 8)
June, SuperMemo Corporation was incorporated in the US with a goal of making it the first company of Polish origin on NASDAQ. The company came close to securing substantial venture capital but ultimately ... closed
September, SuperMemo World released a hypermedia best-selling course of English on CD-ROM, Cross Country (with Genius 2.0, a precursor of SuperMemo 8)
September, precursor of SuperMemo 8, Genius 2.0, received its first award as the hypermedia authoring tool at Softarg 1996, Poland
October, 60,000 readers of Chip in Poland received a CD-ROM with the full version of the hypermedia authoring SuperMemo (Genius 2.0). Free!
November, the first Polish multimedia encyclopedia on CD-ROM was released with SuperMemo as an integrated tool for learning selected encyclopedic material

1997

January, SuperMemo World, Polish veteran of CeBIT and the first Polish company present at Comdex made a strategic turn towards the Internet away from major software fairs. SuperMemo Website at supermemo.com will become SuperMemo World's best marketing tool ever. This also marks the beginning of the accelerated expansion of the concept of spaced repetition around the world!
January, Polish PWN Encyclopedia with SuperMemo was voted the best Polish software product by readers of PC Kurier
February, SuperMemo 8 entered beta-testing. For the first time, beta-testing was run exclusively over the Internet with a dramatic impact on program's reliability
May, over 100 international beta-testers submitted their final reports via the Internet. This SuperMemo 8 beta-testing program alone brought more valuable data than all programs before
May 12, SuperMemo World released Deine Chancen in Deutsch with SuperMemo 8 (first commercial CD-ROM with hypermedia SuperMemo)
June 12, for the first time ever SuperMemo was made available for download from the web
October 22, 80,000 readers of Chip in Poland received a CD-ROM with SuperMemo 8.0 (Free!) and a demo of Advanced English 97
November 10, Advanced English 97 with SuperMemo 8 was released

1998

January 14, SuperMemo 8 was chosen the Product of the Year 1997 by journalists of a respected Polish journal PC Kurier (ahead of MS Internet Explorer 4.0PL)

Product of the Year for SuperMemo

March 20, SuperMemo Library hosted by Michal Hejwosz and Piotr Maksimczyk was inaugurated
May 25, SuperMemo World signed a licensing and distribution contract with Vulcan Media. By September 1998, the two companies will develop the largest network of sales representatives in Poland covering virtually all software resellers in the country. Additionally, SuperMemo technology will become integrated with all new educational titles released by Vulcan Media (including their Multimedia Encyclopedia best-seller)
August 1, SuperMemo World as the first company in Eastern Europe opened an e-commerce store at Yahoo Stores
September 28 - SuperMemo 98 was released
November 27 - SuperMemo 98 was featured among the most successful Delphi applications
December 1 - SuperMemo appeared on DVD as part of the best-selling Polish Multimedia Encyclopedia (PWN, 1999 Edition). This title sold 45,000 copies in the next two years

1999

April 26, 300,000 copies of Easy English CD-ROM were released in Poland. This is the largest run of SuperMemo ever
May 10, SuperMemo MegaMix 99 was released with 319 SuperMemo collections written by users of SuperMemo
July 5, on the 8th anniversary of SuperMemo World, 1,000,000th CD-ROM with SuperMemo has been released
September, SuperMemo for Windows CE was released
October 4, SuperMemo 99 introduced a new concept: the reading list. Reading lists extend the application of SuperMemo to the area of knowledge acquisition, selection, prioritization, and formulation. The reading lists later evolved into a breakthrough concept of incremental reading
November 23, in its probably greatest success ever, SuperMemo was nominated as the Product of the Decade by PC Kurier, Poland (among three other contenders)

Product of the Decade nomination for SuperMemo

2000

January, SuperMemo for Windows CE received Real Mobility Award
March, SuperMemo for Palm Pilot was released
July, SuperMemo World s.c. and Internet Investment Fund, Poland, signed an agreement on the development of a system for Mobile learning with SuperMemo. It later evolved into supermemo.net and ultimately into SuperMemo On-Line at supermemo.com
November, SuperMemo 2000 introduced the concept of incremental reading that makes it possible to read hundreds of articles at the same time. This is probably the single most important development in the history of SuperMemo since the implementation of spaced repetition
December, Polish Orthography SuperMemo CD-ROM was listed among recommended educational tools by the Polish Ministry of Education

2001

April, supermemo.net became the first SuperMemo web application

2002

May, SuperMemo 2002 adopted HTML as the default data format in incremental reading

2004

May, SuperMemo for Pocket PC became the first SuperMemo to adopt the new XML data exchange format
September, SuperMemo 2004 adopted the XML data exchange format (see: Revolution in the pocket)

2005

March, First SuperMemo DVD: Extreme English DVD combined the most popular learning material, Advanced English, with the most widely distributed SuperMemo, Multimedia SuperMemo
May, SuperMemo 98 for Windows was released as freeware
August, SuperMemo method turned 20 years old

2006

SuperMemo 2006 for Windows in conjunction with SleepChart started collecting data needed to study circadian correlates of learning. This opened new vistas to studying (1) the impact of sleep on learning and (2) the impact of learning on sleep

2007

March, SuperMemo 2006 for Windows pioneered tools for tackling learning overload: priority queue, auto-sort and auto-postpone. This made it possible to increase the volume of incremental reading without a detriment to retention of the top priority material
Dec 13, SuperMemo software turned 20 years old

2008

April, Wired Magazine published a 7 page article on the history of SuperMemo
December, a contract with the Polish Ministry of Education brought SuperMemo to 144,000 computers in Polish schools

2009

March, SuperMemo 2008 introduced the optimization of learning based on the analysis of the timing of sleep. SuperMemo thus entered a long road towards the future in which sleep can be optimized for the sake of learning, while learning can be optimized with the view to the timing of sleep. The bridge between the two worlds initiates a process in which truckloads of data are being generated for investigating the relationship between sleep and memory. See: impact of sleep on learning
September, SuperMemo 2008 introduced the concept of incremental video, which is an extension of incremental reading into the world of video. It also made further inroads into the area of visual learning
December, iPhone got its own SuperMemo too

2010

May, sleep data collected with SuperMemo SleepChart was instrumental in building the strongest case against the polyphasic sleep practice to date

2011

July 5, SuperMemo World turned 20. Major celebrations took place in October with many distinguished guests

2012

September, in association with T-Mobile, SuperMemo World conducted the greatest advertising campaign for its products in history
December, SuperMemo World opened SuperMemo Language Center in Poznan, Poland. Using the back up of SuperMemo, the school provides a unique guarantee: "if fail your target exam, you can claim your money back!"

2013

November, after 14 years of slow progress, the concept of Incremental Learning is complete in SuperMemo 16 for Windows. The vision of Knowledge Machine was described two decades ago before the explosion of the web

2014

March, SuperMemo World opened a new field in education: EduAction. The movie Olive Green combines entertainment, with a course of English and the SuperMemo method. Over the next 2 years, the movie will have collected dozens of awards from journals and movie festival reviewers
Summer, SuperMemo entered new platforms: cars and ... kindergartens
November, multimedia version of Advanced English turned 20 years old. It keeps evolving. This best-selling learning material has always been the fastest avenue towards native English vocabulary. Its 2014 release reflects dynamic changes to English and improves item formulations with the view to maximizing their mnemonic power

2015

April, the concept of two variables of long-term memory has now spawned a new approach to spaced repetition with the newest spaced repetition algorithm: Algorithm SM-17. Despite our prior claims, this new algorithm has a major impact on the speed of learning, esp. in intermittent learning where review may frequently be advanced or delayed. By mid 2016, the algorithm met all metrics with flying colors
October, supermemo.com aims to be the new SuperMemo on-line learning hub

2016

January, new tools in SuperMemo help you simulate the process in which a creative brain comes up with solutions to problems. Like a working human brain in slow motion, SuperMemo can bring up related pieces of knowledge, and produce an artificial "train of thought". For details see: Neural creativity. See also how neural creativity came to be

For more details see: SuperMemo News