#TrueOrFalse: Spaced Repetition

By Udeet Datta

The theory: Spaced Repetition

Spaced repetition is a learning technique that incorporates increasing the intervals of time between subsequent reviews of previously learned material in order learn better and more effectively. It has been argued that effectiveness derived from spaced repetition stems from our ability to exploit the psychological spacing effect. This spacing effect is a memory phenomenon that allows our brain to learn better when we space out this process over intervals of time. For example, if you are studying for a test coming up in a week, you do your first session of study today, start another session a day after tomorrow and then you do your final session of study just before the test.

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True or False? We say true

The research says:

Learning something and spacing this over time, rather than amassed all at once, in fact actually does allow that information to be better remembered.[1] Besides being attributed to a phenomenon known as the spacing effect, occasionally called the distributed practice[2] , there are a few other well-known theories which may explain the benefits that spaced practice has on long-term information retention:

  • Whilst practicing spaced repetition, a person retrieves information from memory. This retrieval refers to the process by which something stored in the brain is accessed later. As simple as this may sound, this cerebral process in itself has been shown to actually enhance memory.[3]
  • Another viewpoint puts emphasis on the context of the learning environment. Every time information learnt enters memory, fragments of context are embedded with it. This provides the brain with additional “links” back to the original memory. Hence, by spacing out learning repetitions of information, there are more possibilities for variable contexts to be encoded into memory with the information being learned.[4]
  • Another hypothesis involves the concept of deficient processing. This refers to reduced attention to a certain item, if it is the same one just presented. This occurs when trying to learn a lot in one space of time. Spaced repetition avoids this effect.[5]

How far apart should spaced learning intervals be?

Now the size of each of the intervals is dependent on how long the information needs to be retained for e.g. if there is a test in 1 week, spaced repetitions of 1 day can be quite effective. However if the information is required in 1 year, then spaced intervals of 1 month or so may be more effective.[6]


[1] Sisti, Helene M et al. “Neurogenesis and the spacing effect: learning over time enhances memory and the survival of new neurons.” Learning & memory (Cold Spring Harbor, N.Y.) vol. 14,5 368-75. doi:10.1101/lm.488707

[2] Kang, Sean H. K. “Spaced Repetition Promotes Efficient and Effective Learning.” Policy Insights from the Behavioral and Brain Sciences, vol. 3, no. 1, 2016, pp. 12–19., doi:10.1177/2372732215624708.

[3] Wahlheim,  C.  N.,  Maddox,  G.  B.,  &  Jacoby,  L.  L.  (2014).  The  role of reminding in the effects of spaced repetitions on cued recall:  Sufficient  but  not  necessary.  Journal  of  Experimental  Psychology: Learning, Memory, and Cognition, 40, 94-105.

[4] Glenberg,  A.  M.  (1979).  Component-levels  theory  of  the  effects  of spacing of repetitions on recall and recognition. Memory & Cognition, 7, 95-112.

[5] Magliero, A. (1983). Pupil dilations following pairs of identical and related  to-be-remembered  words.  Memory  &  Cognition, 11, 609-615.

[6] Cepeda,  N.  J.,  Coburn,  N.,  Rohrer,  D.,  Wixted,  J.  T.,  Mozer,  M.  C.,  &  Pashler,  H.  (2009).  Optimizing  distributed  practice:  Theoretical  analysis  and  practical  implications.  Experimental Psychology, 56, 236-246.

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