Spacing
Regardless of the exact method of studying someone chooses to use, it is better to space the sessions out rather than have them close together. Massed presentations means the same information is repeated back to back with no space between them. In contrast, spaced study means there is a gap between presentations that can vary in duration from a few seconds to weeks or even months. When items are spaced, performance is often better on a final memory test. This is referred to as the spacing effect and has been confirmed by hundreds of studies [1, 2]. The spacing effect has been observed across a wide range of tasks as well as learner ages.
It might seem obvious that material needs to be revisited to be properly learned, but many students try to cram a large amount of material in a single session before an exam and are surprised they can’t remember it. Given a fixed amount of time it is always better to spread it over several study sessions [3, 4].
To avoid confusion, it is important to note that the spacing effect refers to information that is studied multiple times. Take the case of trying to learn foreign language vocabulary. Rather than review it ten times in a single session, instead review it two times in each of five sessions. The spacing effect doesn’t refer to different material that is spread over shorter sessions rather than one long session. So if you need to study a whole textbook chapter, spending six 30-minute sessions studying it is not the spacing effect. Although there might be other advantages such as finding it easier to maintain concentration.
For university students, it makes sense to review information within a couple of weeks of initial learning. A revision schedule like this will make it easier to prepare for end of semester exams. Failure to review in the intervening period may result in some concepts being completely forgotten. Most universities in Australia and New Zealand have final exams that cover the material from the entire semester, so it is essential to retain information till the end of the semester. There may be rare special cases such as when a mid-semester test covers the first half of the semester and then a final test exclusively covers the second half. In that case there may be no need to keep reviewing material from the first half of the semester.
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Tip
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Try reviewing material within a couple of weeks of first encountering it. If it is left too long it might be completely forgotten meaning relearning from scratch. |
What is the optimal gap between study sessions?
The optimal gap between study sessions can depend on a lot of factors. The main risk of waiting too long is that the material will be forgotten. One study found that the optimal spacing between study sessions depends on the gap between the final study session and the test [5]. A review of studies by Cepeda and colleagues found that spreading learning over weeks or even months enhanced long term retention [1]. It all comes down to whether the student just wants to remember the material for the final exam, or wants to be able to recall the information in future courses or for their career.
Regardless of how the student is choosing to revise the material such as rereading the material, practice quizzes, or another approach, it is better to space the episodes out rather than have them close together. Those students who have an exam in a month or a test in a couple of weeks are limited in terms of how much they can spread out their study sessions. Also, due to the fact that they can study the day before and may only need to remember the material for a day means that shorter intervals between study sessions are acceptable. In practical terms, those preparing for tests and final exams should space study sessions so that certain facts or topics are a few days apart.
To be more specific, a student might schedule three study sessions each four days apart. In a given study session, they would repeatedly study each item until it could be successfully recalled. That would mean thinking about test revision at least a couple of weeks before the test. The advantage of starting earlier is that if there is trouble learning material, a buffer exists for additional revision sessions. Obviously, if only one week remains before a test study sessions will need to be spaced closer together.
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Tip
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When reviewing for a test revise for a shorter time every day or every couple of days rather than a long cramming session right before the test. |
Foreign language students may want to retain vocabulary even after the course is over. Other students may need to remember knowledge for a final qualifying exam at the end of their degree. In these cases, study sessions with longer intervals that continue after the end of the course may be optimal. During the course, you would also use shorter interval study sessions to prepare for exams.
Consider the situation of aiming for longer term retention, if in a study session the material is easily remembered, then the study session came too soon. This means the time could’ve been spent studying something else. On the other hand if the material is completely forgotten then the interval was too long, meaning that the memory trace from the initial learning is not reinforced making it almost like starting from scratch [6].
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Tip
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Foreign language students might want to revise items every couple of weeks even after the course is over to retain vocabulary for a long time and ultimately become fluent. |
As mentioned, the optimal time between study sessions depends on the retention interval, where the retention interval is the time between the last study session and when the material is tested. Since so many variables are involved related to the learner, and the characteristics of the material, exact study guidelines are difficult and the student might have to experiment to find what works best for them in a given situation. Nevertheless for most students planning to revise each item of information three to four times in the weeks leading up to a test is a good idea.
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Important
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The optimal interval between study sessions varies depends on many variables and is impossible to determine with any precision. Difficult material should be reviewed at shorter intervals to ensure it isn’t completely forgotten before the next review. |
Is an expanding schedule better?
An expanding schedule is when the spacing between subsequent study sessions increases over time. In comparison, a fixed schedule is when the spacing between study sessions remains constant. Expanding schedules are popular in some flashcard applications. Studies have given mixed results to whether expanding schedules are better. Certainly there is no compelling evidence to support their superiority. It’s only clear that a spaced scheduled (whether expanding or fixed) is better than a massed schedule [2, 7].
Combine spacing with testing
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Note
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This section gives a preview of other learning related tools are discussed in other chapters and can be combined with the spacing effect. |
Another useful phenomenon is the testing effect. This refers to the fact that practice quizzing actually helps us learn, as opposed to just giving us an indication of how well we know certain material.
Unfortunately, after our first exposure to information, much of what is learnt is quickly forgotten. In order to retain that knowledge on a semipermanent basis we need to study it multiple times [8]. One strategy that combines spacing and testing is successive relearning. This involves first practicing a task in an initial study session until it is performed correctly. Then, in a series of subsequent sessions, the task is again practiced until it is performed correctly. As discussed previously, it is better for retention to space recall over several sessions rather than for all recalls to occur in a single session.
One popular approach to revision is to utilise flashcard software. Have a deck of cards which includes every topic covered so far in the course. Other alternatives are also effective, such as having a sheet of questions with answers at the end, or having notes with one column for questions and one for answers. Conceal the answer until after you’ve tested yourself.
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Tip
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Use practice quizzing / testing combined with spacing to boost your retention of material |
How many relearning sessions?
A common question is how many times should a given piece of information be studied. It’s difficult to give a definitive answer to this question as there are many variables involved such as how difficult the material is. A starting point would be to practice recalling until you achieve three correct recalls in the initial session. Then in each of three separate subsequent study sessions relearn the item until you achieve one correct recall [9].
References
[1] N. J. Cepeda, H. Pashler, E. Vul, J. T. Wixted, and D. Rohrer, “Distributed practice in verbal recall tasks: A review and quantitative synthesis.,” Psychological bulletin, vol. 132, no. 3, p. 354, 2006.
[2] S. K. Carpenter, N. J. Cepeda, D. Rohrer, S. H. K. Kang, and H. Pashler, “Using spacing to enhance diverse forms of learning: Review of recent research and implications for instruction,” Educational Psychology Review, vol. 24, pp. 369–378, 2012.
[3] J. Dunlosky and K. A. Rawson, “Practice tests, spaced practice, and successive relearning: Tips for classroom use and for guiding students’ learning.,” Scholarship of Teaching and Learning in Psychology, vol. 1, no. 1, p. 72, 2015.
[4] Y. Weinstein, C. R. Madan, and M. A. Sumeracki, “Teaching the science of learning,” Cognitive research: principles and implications, vol. 3, pp. 1–17, 2018.
[5] N. J. Cepeda, E. Vul, D. Rohrer, J. T. Wixted, and H. Pashler, “Spacing effects in learning: A temporal ridgeline of optimal retention,” Psychological science, vol. 19, no. 11, pp. 1095–1102, 2008.
[6] M. Wiseheart, C. E. Küpper-Tetzel, T. Weston, A. S. N. Kim, I. V. Kapler, and V. Foot-Seymour, “22 Enhancing the Quality of Student Learning Using Distributed Practice,” 2019.
[7] J. D. Karpicke and H. L. Roediger, “Is expanding retrieval a superior method for learning text materials?,” Memory & cognition, vol. 38, no. 1, pp. 116–124, 2010.