Spaced repetition in education: Students learn four months worth of material in one hour

6 Nov

“The data suggest Spaced Learning is more efficient in comparison to standard teaching.”

That is the major finding of an important  paper by Kelley and Whatson that compares space repetition instruction to standard teaching.

Here is a chart presenting the dramatic results:


This chart shows that in their randomized experiment there was no significant difference between students who received standard teaching for four months and students who studied the same material for an hour using spaced repetition.

Here is their description of their results:

“The test data allowed a comparison of control group scores after four months teaching and experimental group scores after an hour of Spaced Learning. In Condition 1 there were a number of restrictions intended to limit the impact of prior learning in experimental groups. These groups were in an earlier academic year, tested nine months earlier than controls, and had not studied the first Biology course. The five day gap between learning through Spaced Learning and the test in effect eliminated STM accounting for test scores. Surprisingly, the experimental groups’ high-stakes test scores after an hour’s Spaced Learning were not significantly different from controls’ test scores after four months teaching”

I can not emphasize enough the importance of this work and suggest that you read the paper in its entirety.

For more on spaced repetition learning, and a chance to try it yourself, see my post about Memrise.

2 Responses to “Spaced repetition in education: Students learn four months worth of material in one hour”

  1. Tomas December 3, 2013 at 9:10 pm #

    I smell a rat.

    The experiment that apparently inspired “spaced learning” was, according to the book written by its inventor Paul Kelley, an experiment on cells from the hippocampus of rats, suspended in salt solution. Researchers apparently found that by stimulating the cells three times with 10 minute spacing, they got some kind of long term change.

    Paul Kelley, a teacher, apparently read this and decided that three PowerPoint presentations given to students, separated by 10 minute breaks, might improve learning and memory.

    I am deeply skeptical of this kind of reasoning. Giving PowerPoint presentations with 10 minute breaks may or may not be an effective learning strategy, but claims that the strategy is grounded in neuroscience looks incredibly tenuous to me. The paper writing up the experiments gives lots of impressive looking neuroscience references, to studies looking at memory in honeybees and nightingales, among others. But I can see not a shred of evidence that there is anything to link what is going on in the brains of the students to what is going on in the brains of rats, birds, or bees. It looks to me like total neurobunk – using neuroscience to make education look like it’s based on science, when the real evidence that counts – properly controlled independent trials – is lacking.

    As well as there being little to link spaced learning with neuroscience, I can see little to link it with the well established literature on spaced repetition (as originated by Ebbinhaus and implemented in programs like Anki and Memrise). I know of nothing in that literature to suggest that learning something three times with two ten minute breaks is some kind of key to long term learning, as the supporters of “spaced learning” claim.


  1. How spaced repetition teaching works | peakmemory - November 7, 2013

    […] Yesterday, I blogged about a study that compared spaced repetition teaching to standard instruction. Here is a pdf that describes, in detail, the teaching methods used in the study. […]

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