Hermann Ebbinghaus

Hermann Ebbinghaus

Spaced Repetition Systems

On my first day of high school I was given a slip of paper with the combination to my book and coat locker. I carried that slip of paper with me for a week, glancing at it several times a day until the set of three numbers was firmly in my memory. After that point, I no longer needed the slip of paper to recall the opening combo—all was well for freshman year. When I went back to school as a sophomore, however, I found that I no longer had the faintest idea of what the locker combination was. I had forgotten it.

RESEARCH

The German psychologist Hermann Ebbinghaus studied this phenomenon in 1885 and noticed a remarkable thing. When people learned factual information, recall decays over time, but when a person relearns something, the time it takes to forget that fact increases, i.e. the person remembers it for a longer time.

Ebbinghaus’ work was expanded on in subsequent years. In 1930 Theophilos Boreas discovered that the rate of memory decay was logarithmic. Other researchers found that the kind of information has an effect on our ability to learn and remember. Material that is contextual or relevant to the learner is more easily retained, in contrast to the random sounds that Ebbinghaus worked with. In the 1970s, Sebastian Leitner developed a system to improve upon the efficiency of using flash cards for learning. In Leitner’s system, well known facts, those which are answered correctly, come up less frequently during memorization because the learner already knows them. Instead, the learner spends more time with facts that are more difficult to learn. These systems are now –referred to as Spaced Repetition Systems (SRS).

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CURRENT TOOLS

Computers and the Internet have improved the possibilities even more. Once flash cards go digital, there are numerous benefits. Rather than using a manual sorting system, the computer program can track which questions need to be asked more frequently. Questions can also be asked forwards and backwards. If I were learning Spanish and I saw the word ‘casa’ I would know or find that the answer was ‘house’. When the card is digital, I can just as easily be asked to translate in the other direction, from English to Spanish. Of course, the information can also be relayed to learners with pictures, sounds and video.

scanned image of pencil drawing showing a slab of dimensions a and b. The formula for inertia of the object is below.

Anki deck showing inertia formula for a slab. Anki supports images and other digital files.

There is one platform, Anki, which does all these things and allows instructors or students to create flash card decks for study. The time investment in creating decks is returned once you are able to share your questions with multiple students, and there are many freely available decks already published.

BEYOND FLASH CARDS

In this day of internet searches and querying Siri for basic information, what place does recall of information have in learning? Isn’t it more important to be able to find some thing out than to know that thing? Largely, it depends. Some information is so basic that it really is a first step in broadly comprehending a larger concept. In some cases, like learning a foreign language, there really isn’t a substitute for knowing the word ‘rest room’. Would you really want your surgeon to have to consult Google when repairing a heart valve?

The essence of learning and teaching can’t and shouldn’t be relegated to rote memorization though. If you can get students to apply the basic facts, they’ll be building recall while simultaneously learning the larger context.

RESOURCES