Spaced Repetition for Efficient Learning

Summary

When should one review? In the morning? In the evening? Any old time? The studies demonstrating the spacing effect do not control or vary the time of day, so in one sense, the answer is: it doesn’t matter - if it did matter, there would be considerable variance in how effective the effect is based on when a particular study had its subjects do their reviews. So one reviews at whatever time is convenient. Convenience makes one more likely to stick with it, and sticking with it overpowers any temporary improvement. If one is not satisfied with that answer, then on general considerations, one ought to review before bedtime & sleep. Memory consolidation seems to be related, and sleep is known to powerfully influence what memories enter long-term memory, strengthening memories of material learned close to bedtime and increasing creativity; interrupting sleep without affecting total sleep time or quality still damages memory formation in mice. So reviewing before bedtime would be best. (Other mental exercises show improvement when trained before bedtime; for example, dual n-back.) One possible mechanism is that it may be that the expectancy of future reviews/tests is enough to encourage memory consolidation during sleep; so if one reviews and goes to bed, presumably the expectancy is stronger than if one reviewed at breakfast and had an eventful day and forgot entirely about the reviewed flashcards. (See also the correlation between time of studying & GPA in Hartwig & Dunlosky2012.) Neural growth may be related; from Stahl2010: Recent advances in our understanding of the neurobiology underlying normal human memory formation have revealed that learning is not an event, but rather a process that unfolds over time.16,17,18,[Squire2003 Fundamental Neuroscience],20 Thus, it is not surprising that learning strategies that repeat materials over time enhance their retention.20,21,22,23,24,25,26 …Thousands of new cells are generated in this region every day, although many of these...