The August issue of Current Directions in Psychological Science contains an interesting article titled: Increasing Retention Without Increasing Study Time (available free). It’s written by psychologists Doug Rohrer and Harold Pashler.

Here are some interesting observations from the study:

  1. “[We found] a single session devoted to the study of some material should continue long enough to ensure that mastery is achieved but that immediate further study of the same material is an inefficient use of time.”
  2. “In essence, overlearning simply provides very little bang for the buck, as each additional unit of uninterrupted study time provides an ever smaller return on the investment of study time…There are, however, situations in which overlearning is desirable. For instance, overlearning appears to be effective in the short term and therefore might be a fine choice for learners who do not seek long-term retention.”
  3. “The benefit of distributing a fixed amount of study time across two study sessions—the spacing effect—depends jointly on the interval between study sessions and the interval between study and test.”
  4. “In the first of these studies, students studied Swahili–English word pairs. The ISI [spacing between two study sessions] ranged from 5 minutes to 14 days, and the RI [the time after studying and before the test] was 10 days. ISI had a very large effect on test scores, with the 1-day ISI yielding the best recall.”

I’m not surprised to see a close correspondence between these results and what I observed of the straight-A students I studied. In particular, notice that Quiz-and-Recall eliminates overlearning by having students only revisit ideas that gave them trouble. Similarly, my claims that you should process information into ideas before recording them in your notes, and then study in small chunks spread over many days (explained here and here), fit nicely with the finding that separated study sessions perform far superior to one massed cram session.

(Thanks to Wray Herbert for finding this article)