The Early Career Framework states that teachers must learn that... requiring pupils to retrieve information from memory, and spacing practice so that pupils revisit ideas after a gap are also likely to strengthen recall.
Shorter practice and study separated by a period of time typically improves retention compared to massed study in one long session. This is known as the spacing effect. An array of practical activities for implementing spaced practice in regular classroom practice are already present. Homework assignments targeting both old and new material, cumulative and/or weekly formative assessments, short review sessions, and implementation of a spiral curriculum all have an intrinsic spacing component under full teacher control. Also, merging retrieval and spacing creates optimal learning situations; retrieval practice followed by feedback is highly effective because this feedback serves as a spaced exposure. Students can apply spaced practice by designing a study schedule where they space their study sessions over time in a thoughtful way instead of cramming the night before an exam.
The research on spaced practice suggests that retention is significantly improved when students are given a number of practice problems relating to a topic and distributed across a period of time.
Spaced practice or distributed practice is the idea that practising a particular skill or retrieving particular information is more effective when spread over time, rather than repeated sequentially over a short time period.
In the late 1890s, the German experimental psychologist, Herman Ebbinghaus, reported the “spacing effect”. He was the first person to describe the forgetting curve, which shows how quickly memories fade after learning. Note the red graph: about 50% is lost after one day.
Practising or rehearsing slows down the forgetting process, with spaced practice much more effective than massed practice (without spaces). Each green line on the graph is a rehearsal, where the memory goes back to 100% and then decays again, but in a more gradual manner.
When memory is encoded and stored in the brain, connections between neurons are formed. Memories are represented by networks of interconnected neurons and when we learn something new, a new network is formed. This process of biological consolidation of memories requires resources and time. Research shows that resting (and, better yet, sleeping) after learning enhances our ability to remember the information. Spacing out the repetitions may allow the brain machinery to work without interference between the two events.
Another reason why spacing is effective is that, over time, memories decay and becomes less and less accessible. By attempting to relearn something after a period of time we are actually reconstructing the information itself, and even more importantly, we are reconstructing the pathways that lead to it, so that it will be more accessible next time. We can think of the initial learning in terms of building a house. Then, every time we want to get to the house we have to reconstruct the route leading to it, and sometimes find a new route. With time, we mostly forget the routes, and must reconstruct them to reach the house. So the reason spacing is effective, according to this explanation, is that it triggers active effortful reconstruction of the retrieval pathways, in other words spacing induces more effective retrieval practice.
Another advantage for spaced learning is that the passage of time also changes the context of learning. If time has passed since our last practice, we will most likely approach the information in a different way, and use different cues or triggers. Using the house analogy, it is like learning several different routes to the house from different initial locations, which ultimately will allow us to get there easily, no matter where we are. By practising in varied contexts, we are making sure the information will be much more accessible, in different situations and with different cues.
The practice should be effortful to be effective. We should concentrate on reconstructing pathways, not just revisiting the information. By spacing the repetitions we are making it harder on ourselves, but the effortful reconstruction process is what makes practice beneficial since we are building stronger pathways to the memory. Rest is also crucial to memory. Following the effort of reconstruction it is better to rest in order to allow the pathways to consolidate. A second immediate repetition is not challenging enough and consequently not so effective. In addition, it may interfere with the consolidation processes of the previous attempt. To apply effective spaced practice we should work hard and then have a good rest.
First and foremost, students should be educated about the benefits of spaced practice. Spaced practice should be incorporated into in-class activities and assessments as well as out-of-class exercises and homework. For example, in order to complete an in-class task, students should be required to recall key facts, concepts or ideas that were learned earlier in the course. To maximize the benefits, students should be encouraged to recall the information without referring to their notes, books or other course materials. Feedback following the activity is important to ensure that misunderstandings are corrected immediately. All quizzes and exams, not just the final exam, should be cumulative, thus requiring students to use spaced practice when preparing for formal assessments. Like in-class activities, homework should require students to regularly retrieve that which was learned earlier in the course.
There are a few reasons the spacing effect exists:
1. Priming
Priming means an initial exposure to a stimulus helps with later understanding.
The idea is similar to a priming coat of paint. The base layer makes the colour go on much more easily. The same goes for learning. When you increase the amount of practice, you get a priming effect for later learning events. This base knowledge makes learning easier in the following sessions.
2. Long-term memory consolidation
Traditional classroom learning (otherwise known as massed learning) usually only allows students to store information in short-term memory. But when learning sessions are spaced and repeated, long-term memory is activated and learning can last longer. Students can then retrieve the information from their memories in the future.
3. Contextual differences
When learning sessions are broken up, the context surrounding them is different. Students might learn on a different day, in a different location, or from different media sources. They’ll probably receive a wide range of stimuli from different situations and encode them in their memories, associating them with what they’re learning. Since context helps enable memory retrieval, involving more stimuli in distributed learning sessions increases contextual cues, especially since there’s more time between them. Providing more varied opportunities for memory recall helps create an environment for students to remember material better.
Note: Multimodal learning, the practice of teaching in various ways to stimulate different senses, can maximize this benefit.
4. Complex thinking
When students learn concepts through distributed practice, retrieval requires complex thought. When learning is distributed, enough time has passed that retrieval requires actual access to memory storage, not just short-term rehearsal. Students also pay more attention when repetition is further apart, since they can’t just rely on the familiarity of something they recently learned.
5. Procedural memory
Repeating an activity enough can train your brain to automatically remember it. Eventually, you can perform certain tasks without conscious effort. One of the most effective ways to increase the effectiveness of procedural memory is distributed practice. By spacing out learning opportunities, knowledge can become procedural.
Spacing links to another important and beneficial concept: interleaving, i.e., mixing up tasks rather than doing them in blocks of the same type of task. When we introduce a time delay between studying and re-studying, other material will be covered during any class time in-between. This interleaving can have additional benefits, perhaps by helping learners to more clearly see the links and the differences between different topics or sub-topics. In math, for example, interleaving can help learners to choose the correct strategy to solve a problem, and the researchers who study these effects therefore advise against giving students exercises that feature several consecutive examples of the same kind of problem.
Jonathan Firth (@psychohut) is a high school teacher of psychology in Scotland with a background in psychology and applied linguistics. He has written some school textbooks on psychology that cover a range of topics, but his main areas of interest/research are long-term memory and metacognition. He wrote a guest blog post for The Learning Scientists all about the topics of spacing and interleaving and it is well worth a read.
The Education Hub has written further about Spacing Practice and their article is worth a read.
Spacing is a powerful strategy that boosts learning by spreading lessons and retrieval opportunities out over time so learning is not crammed all at once. By returning to content every so often, students’ knowledge has had time to rest and be refreshed. You can download a free guide on how to use spaced retrieval practice to boost learning from The Retrieval Practice website.
The Chartered College of Teaching have also produced a guide on spacing and interleaving which is free to download from their website.
@TeacherToolkit has also written about spaced practice on his blogsite.
References
[Further reading recommendations are indicated with an asterisk.]
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Agarwal, P. K., Finley, J. R., Rose, N. S., & Roediger, H. L. (2017) Benefits from retrieval practice are greater for students with lower working memory capacity. Memory, 25(6), 764–771. https://doi.org/10.1080/09658211.2016.1220579 .
Allen, B. and Sims, S. (2018) The Teacher Gap. Abingdon: Routledge. Baddeley, A. (2003) Working memory: looking back and looking forward. Nature reviews neuroscience, 4(10), 829-839.
Black, P., & Wiliam, D. (2009) Developing the theory of formative assessment. Educational Assessment, Evaluation and Accountability, 21(1), pp.5-31. Chi, M. T. (2009) Three types of conceptual change: Belief revision, mental model transformation, and categorical shift. In International handbook of research on conceptual change (pp. 89-110). Routledge.
Clark, R., Nguyen, F. & Sweller, J. (2006) Efficiency in Learning: Evidence-Based Guidelines to Manage Cognitive Load. John Wiley & Sons. Cowan, N. (2008) What are the differences between long-term, short-term, and working memory? Progress in brain research, 169, 323-338.
*Deans for Impact (2015) The Science of Learning [Online] Accessible from: https://deansforimpact.org/resources/the-science-oflearning/ . [retrieved 10 October 2018]. Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013) Improving students’ learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest, Supplement, 14(1), 4–58. https://doi.org/10.1177/1529100612453266 .
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*Rosenshine, B. (2012) Principles of Instruction: Research-based strategies that all teachers should know. American Educator, 12–20. https://doi.org/10.1111/j.1467-8535.2005.00507.x .
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Willingham, D. T. (2009) Why don’t students like school? San Francisco, CA: JosseyBass. Wittwer, J., & Renkl, A. (2010) How Effective are Instructional Explanations in Example-Based Learning? A Meta-Analytic Review. Educational Psychology Review, 22(4), 393–409. https://doi.org/10.1007/s10648-010-9136-5 .