Spaced Repetition Systems (SRS)

I ran across an HN post (again) on Piotr Wozniak:

“The reason the inventor of SuperMemo pursues extreme anonymity, asking me to conceal his exact location and shunning even casual recognition by users of his software, is not because he’s paranoid or a misanthrope but because he wants to avoid random interruptions to a long-running experiment he’s conducting on himself. Wozniak is a kind of algorithmic man. He’s exploring what it’s like to live in strict obedience to reason. On first encounter, he appears to be one of the happiest people I’ve ever met.”

I’m going to try read up on this and see how SRS works. Apparently there are several tools that are available that make use of this technique:

There’s a nice graph that illustrates the idea on this in’s article: “Want to Remember Everything You’ll Ever Learn? Surrender to This Algorithm”:

SuperMemo SRS graph

There’s a more complicated graph from Gradint:

Gradint graph on graduated learning

What could be potential applications for this? Well if you’re a learner-centered facilitator, it might be helpful to know what are the upper and lower bounds of the intervals to facilitate better learning. As the Wikipedia entry on Spaced Repetition on Pimsleur’s Graduated-Interval Recall indicates:

“Graduated-interval recall is a type of spaced repetition published by Paul Pimsleur in 1967.[9] It is used in the Pimsleur language learning system 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. (emphasis mine)

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 software project (Gradint) to schedule its audio-only lessons.”

It might be worthwhile for me to actually read up on this, starting with the Frank N. Dempster’s “The spacing effect: A case study in the failure to apply the results of psychological research.” The abstract indicates:

“The spacing effect would appear to have considerable potential for improving classroom learning, yet there is no evidence of its widespread application. I consider nine possible impediments to the implementation of research findings in the classroom in an effort to determine which, if any, apply to the spacing effect. I conclude that the apparent absence of systematic application may be due, in part, to the ahistorical character of research on the spacing effect and certain gaps in our understanding of both the spacing effect and classroom practice. However, because none of these concerns seems especially discouraging, and in view of what we do know about the spacing effect, classroom application is recommended. (emphasis mine).”

Time to Start Reading!

Further References:


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