One of the most common study habits students pick up is cramming. Cramming comes naturally to students as the natural solution to procrastination – why not relax for weeks and save all the pain for a short period of time? But one of the biggest problems with cramming is that everything learned this way gets stored in short term memory, and seldom finds its way into long term memory banks.
How can we move knowledge into our long-term memories? Let’s talk about spacing and interleaving.
The effectiveness of spacing and reviewing information in sessions spaced out over days, weeks, or months, has strong evidence across multiple studies.
In one language learning study, spanning 9 years, spacing review of vocabulary over longer time-periods led to better recall up to 5 years after the learning period. The vocabulary was reviewed by participants in three different groups: 26 review sessions, but spaced out every 2, 4, or 8 weeks. After these 26 sessions, the groups were tested every year for 5 years. The results? On the final test those who had spaced out learning the most – sessions 8 weeks apart – performed best, with 54 percent of words recalled. Spacing helps.
There is another way to make learning more fruitful and effective: interleaving, in other words, mixing related study topics.
We have all had the pleasure of studying math. Most math textbooks are arranged topic by topic, rather than mixed. Researchers at the University of South Florida taught four related geometry techniques to two different groups. One group, “blockers”, learned techniques and completed practice problems in blocks: learn one technique, practice it; learn the next technique, practice it; and so on. Whereas the other group, “mixers”, first learned all four techniques and then completed mixed practice problems.
Interestingly, the accuracy of “blockers” was 30% higher when completing those practice problems. However, one week later, on a final test of all concepts the “mixers” had three times the accuracy of the group who practiced in blocks: 60% vs. 20%. The earlier accuracy of the “blockers” was a false friend. Interleaving helps.
This is exactly why I enjoy teaching test prep: TOEFL, TOEIC, SAT, ACT, and others. First, students select a date for the test, and then we use spacing to plan backward for lessons, homework, and mock tests. And interleaving is a natural part of these tests: mixed math concepts in one section and mixed grammar rules in another.
How we know this works
How do I know spacing and interleaving help my students? Several months after their tests, they must write their college application essays. When editing, my students refer to the same grammar rules we practiced months earlier for the SAT.
How can we all design our studying around these findings? Plan backward from tests: leverage spacing, by testing yourself multiple times, before and after your tests; and design interleaved study session on related topics rather than “blocking” topic by topic.
Stop cramming; start planning.