University of South Florida psychologist Doug Rohrer decided to explore this question scientifically. Working with Hal Pashler of the University of California, San Diego, he had two groups of students study new vocabulary in different ways. One group ran through the list five times; these students got a perfect score no more than once. The others kept drilling, for a total of ten trials; with this extra effort, the students had at least three perfect run-throughs. Then the psychologists tested all the students, some one week later and others four weeks later.
The results were interesting. For students who took the test a week later, those who had done the extra drilling performed better. But this benefit of overlearning completely disappeared by four weeks. In other words, if students are interested in learning that lasts, that extra effort is really a waste. They should instead spend this time looking at material from last week or last month or even last year.
Researchers concluded that once mastery was achieved it was better to leave that subject alone for a while and return to it later. They actually found that an optimal "study break" of about a month resulted in long-term learning-- something they refer to as the "spacing effect".
Is this "spacing effect" an argument for the spiral approach? Perhaps so, yet it does seem to be a well executed spiral in which the content is first studied to mastery and then revisted for reinforcement later. This is certainly not the haphazard "spiral" I've witnessed my children being subjected to with Everyday Math and seems to be more in keeping with Saxon's idea of a spiral curriclum and to a more limited degree with Singapore Math's "spiral".
Just to be clear, it has absolutely no resemblance to the Everyday Math "spiral".
I hope they keep looking into this subject. Children have such precious little time to learn so many important things. Imagine all that could be accomplished if we implemented teaching and study skills that were actually efficient.
That would be a nice change.
Source: Back to School: Cramming Doesn't Work In The Long Term
ABSTRACT—Because people forget much of what they learn, students could benefit from learning strategies that yield long-lasting knowledge. Yet surprisingly little is known about how long-term retention is most efficiently achieved. Here we examine how retention is affected by two variables: the duration of a study session and the temporal distribution of study time across multiple sessions. Our results suggest that 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. Our data also show that 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. We discuss the practical implications of both findings, especially in regard to mathematics learning.
Increasing Retention Without Increasing Study Time
cross posted at Kitchen Table Math