Ebbinghaus also discovered the spacing effect whereby he found he could remember something with fewer repetitions if he spread them out than if he crammed them all into a short space of time. Or, to put it his way (and you’ll probably re-read it about six times before you give up…):
38 repetitions, distributed in a certain way over the three preceding days, has just as favorable an effect as 68 repetitions made on the day just previous … This makes the assumption probable that with any considerable number of repetitions a suitable distribution of them over a space of time is decidedly more advantageous than the massing of them at a single time. (Ebbinghaus, 1885: 89)
This he called the ‘spacing effect’ and it is the science underlying the learning technique known as ‘spaced repetition’. The effectiveness of spaced repetition has been studied repeatedly in the intervening century and the finding is quite robust. In this excerpt, spaced repetition is referred to as ‘distributed practice’ (because it also applies to motor skills).
Moss (1996) reviewed 120 articles on the distributed practice effect, across a wide range of tasks … in each case, over 80% of studies showed a distributed practice benefit (Cepeda et al, 2006: 355).
Interestingly, the effect is not prominent for intellectual skills like maths but applies very well to verbal and motor skills. Also interestingly, if you have not done any work and have an exam tomorrow, then cramming like crazy is, in fact, the correct strategy to use.
- Ebbinghaus, H. (1885) Memory: A Contribution to Experimental Psychology [Online], Available: http://psychcentral.com/classics/Ebbinghaus/
- Cepeda, N., Pashler, H., Vul, E., Wixted, J., Rohrer, D. ‘Distributed Practice in Verbal Recall Tasks: A Review and Quantitative Synthesis’ Psychological Bulletin 2006, Vol. 132, No. 3, 354–380 [Online] Available: http://uweb.cas.usf.edu/~drohrer/pdfs/Cepeda_et_al_2006PsychBull.pdf