This is the third in our blogpost series on Peter C. Brown, Henry L. Roediger III & Mark A. McDaniel’s seminal book on the science of learning, Make It Stick: The Science of Successful Learning (Harvard University Press, 2014). This week we focus on the third chapter, ‘Mix Up Your Practice’. See here for our blogpost on the first chapter and here for the second.
Jonathan Beale, Researcher-in-Residence, CIRL
This chapter emphasises the importance of variation for effective learning. It focuses on three strategies in particular: interleaving, varied practice and spaced practice. (For definitions of these terms, see the first chapter blogpost, claim 4.)
The key benefit of these practices, combined, is summed up as follows:
‘Practice that’s spaced out, interleaved with other learning, and varied produces better mastery, longer retention, and more versatility’ (p. 47).
Practice of this kind requires greater effort, but effortful retrieval is beneficial for learning.
Practice and study are far more effective for learning when divided into periods over time (p. 47). But when we space out practice and study, they often feel less productive. This is because the spaces cause memory to no longer be fresh in our minds: ‘some forgetting has set in and you’ve got to work harder to recall the concepts’. But the additional effort required to retrieve what we have learned helps to make our learning stronger (p. 48, see also p. 63). By contrast, we retain very little of what we learn through massed practice in the long-term. (For a definition of ‘massed practice’, see our first chapter blogpost, claim 3.)
The authors outline some of the neuroscience behind why spaced practice is more effective for learning than massed practice. When we perceive the world, our brains convert the perceptual data from our senses into electrical and chemical signals, through which our minds form mental representations of what we have perceived. The neurological process where perceptual data is converted into mental representations is called encoding. The new mental representations formed through this process are called memory traces (p. 72). Consolidation is the process of strengthening mental representations in our long-term memory (p. 73).
Keeping these notions in mind, spaced practice is more effective than massed practice because it,
‘appears that embedding new learning in long-term memory requires a process of consolidation, in which memory traces … are strengthened, given meaning, and connected to prior knowledge’.
This process ‘unfolds over hours and may take several days’ (p. 49), for several reasons. First, this time period is required for memory consolidation to take place (p. 63). Second, for learning to be durable, we need time in which we can mentally rehearse what we have learned, to remember it better and apply it in other contexts. Third, by incorporating time gaps, we have to make increased effort to retrieve our learning, which can make our learning stronger:
‘The increased effort required to retrieve … learning after a little forgetting has the effect of retriggering consolidation, further strengthening memory’ (p. 49).
How long should intervals be when we space practice? The authors answer as follows:
‘At a minimum, enough time so that a little forgetting has set in … but you do not want so much forgetting that retrieval essentially involves relearning the material’ (p. 63).
The authors add that it needs to be ‘enough [time] so that practice doesn’t become a mindless repetition’. How much time would this be? One answer is given when we take into account the crucial role that sleep plays in memory consolidation – the importance of which is being increasingly shown in research in neuroscience and psychology. On this, the authors write:
‘Sleep seems to play a large role in memory consolidation, so practice with at least a day in between sessions is good’ (pp. 63-4).
So, as a rough guide, allowing at least a day between intensive periods of practice or study has significant learning benefits.
As a simple strategy for spaced practice, the authors recommend flashcards. This is because between ‘repetitions of any individual card, you work through many others’. Flashcards can function as a means of spacing out and mixing up learning, if they are constructed such that they encourage movement between subject areas (p. 64).
While it is good to allow some time for forgetting to set in such that effortful retrieval practice is required to recall learning, the authors warn against allowing too long and recommend strategies to ‘interrupt the forgetting’ (p. 60). For example, in discussion of the typical lecture format or a multiple-day conference, which the authors criticise as typically taking the form of massed practice, the authors recommend that as strategies to ‘interrupt the forgetting’, give students or delegates ‘a quiz at the end of a conference and follow it with spaced retrieval practice’ (pp. 59-60).
Throughout the book so far, the authors have drawn upon evidence from the science of learning to show that some effective learning strategies feel slower than less effective ones. An example is interleaving: when we interleave our study or practice of subject areas, the learning feels slower than when we study or practice through massed practice. The authors point out that it not only feels slower, but sometimes learning really is less effective in the early stages than with massed practice. To illustrate, the authors outline a case study where students interleaved their study of problems in geometry. Interleaving problems impeded the students’ performance during initial learning, but boosted their final performance significantly (p. 50).
The authors outline outline additional advantages for learning of interleaving in this chapter to those put forward in previous chapters. Interleaving not only complements but can function as a form of spaced practice: ‘Interleaving two or more subjects during practice … provides a form of spacing’. Interleaving can also develop students’ ‘ability to discriminate … between different kinds of problems and select the right tool from [their] growing toolkit of solutions’. The authors recommend that when interleaving in teaching, we switch to a new topic not upon completing a topic, but before completion (p. 65).
Varied practice helps to contextualise learning and adapt what we learn so we are better prepared to apply our learning to various situations. Varied practice ‘improves your ability to transfer learning from one situation and apply it successfully to another’ (p. 51). It develops our ‘ability to assess changing conditions and adjust responses to fit’.
To illustrate the advantages of varied practice, the authors contrast it with massed practice and ‘blocked practice’: learning in a linear manner, only moving onto a new topic or area of practice once the previous stage in the sequence has been completed (p. 65).
To illustrate the advantages of varied practice over massed practice, the authors outline a case study where children practised throwing beanbags into buckets. One group mixed the distance between buckets, but never threw beanbags into buckets three feet away; the other group only practised throwing beanbags into buckets three feet away. When the two groups were challenged to throw beanbags into buckets three feet away, the group that threw beanbags only into buckets three feet away performed significantly worse than the group who varied their practice but never threw beanbags into buckets three feet away (p. 46).
The authors outline some of the neurological evidence that supports the learning benefits of varied practice over massed practice. Current evidence suggests that since the learning we gain from massed practice is less challenging, it becomes encoded ‘in a simply or comparatively impoverished representation than the learning gained from the varied and more challenging practice’ (pp. 51-2).
The writers warn against taking interleaving and varied practice too far, by drawing attention to the risks for learning which can arise if excessive focus on interleaving and varied practice results in insufficient focus on other important areas of learning. They warn against ‘placing too much emphasis on variety runs the risk of underemphasizing repeated retrieval practice on the basics’, and emphasise the importance of ensuring that students engage in repeated retrieval practice on a subject’s fundamental areas.
So, while the authors highly recommend interleaving and varied practice as learning strategies, these should not be employed at the expense of repeated retrieved practice on fundamental subject areas. Repeated retrieval practice is ‘crucial’, the authors write, ‘to long-term retention’ (p. 58).
Relatedly, the authors also recommend that we be careful to avoid the ‘familiarity trap’: ‘the feeling that you know something and no longer need to practice it’ (p. 64). Sometimes this is a consequence of massed practice; massed practice can produce ‘momentary strength’: the ‘heightened performance during the acquisition phase of a skill’. During this phase, we can get the feeling that we are learning an area very well. The possession of momentary strength in itself does not, however, lead to long-term learning. Effective learning processes such as interleaving, spaced practice and varied practice do not generate momentary strength; the acquisition of knowledge through these methods is slow and does not produce the fast improvement which we experience through massed practice. But the long-term learning benefits of such methods are greater (p. 63).
This chapter continues to emphasise the importance of reflection in learning. Reflection, the authors write, ‘is a form of retrieval practice …, enhanced with elaboration’ (p. 66). ‘Elaboration’ refers to ‘the process of giving new material meaning by expressing it in your own words and connecting it with what you already know’ (p. 5). The authors suggest that one of the differences ‘between those who do and don’t [learn] is whether they have cultivated the habit of reflection’ (p. 66). (On reflection, see the final practical strategy in our second chapter blogpost; on elaboration, see the Recommended Practical Strategies section of our first chapter blogpost.)
A strategy the authors recommend is that students reflect upon their learning by writing down daily and weekly summaries of what they did, what went well and what they might do differently next time. Daily, weekly and monthly reviewing of learning has been shown to have significant benefits – for example, in Barak Rosenshine’s influential 2010 article, ‘Principles of Instruction’. (On Rosenshine on reviewing, see this blogpost.)
Considering what we might do differently next time through reflection is a form of mental rehearsal, which the authors also emphasise as an important learning strategy. Mentally rehearsing what we could do involves retrieving prior learning, consolidation, contextualising learning by considering ways in which it can be applied and connecting it with our lives, and connecting learning with other areas of our knowledge. (On contextualising learning, see our first chapter blogpost, claim 10.)
There are also some disciplines in which mental rehearsal is vital for reaching mastery, given certain limits circumscribed by the discipline. For example, reflection and mental rehearsal are vital for reaching mastery in sport, given the limits on the amount of time athletes can spend doing physical exercise. It would be counterproductive for athletes to engage in physical activity beyond a certain number of hours per day, so to continue forms of practice and learning beyond physical activity, other forms of practice are required. Reflection and mental rehearsal offer ways of engaging in practice which do not add to the physical fatigue of participating in a physical sport (p. 62).
Developing discrimination skills
A significant advantage of interleaving and varied practice is that ‘they help us learn better how to assess context and discriminate between problems, selecting and applying the correct solution from a range of possibilities’. This relates to contextualisation: learning is most effective when it is contextualised.
This advantage makes interleaving and varied practice more applicable to the ways that we apply learning in our lives. The authors give several examples of how spacing, interleaving and variability are ‘natural features of how we conduct our lives’. (p. 66). The problems that we typically encounter in our lives are often unpredictable and do not follow a linear sequence. For learning to be practically applicable to the unordered manner in which problems often present themselves, ‘we must be adept at discerning “What kind of problem is this?” so we can select and apply an appropriate solution’ (p. 53). Massed practice, by contrast, is less applicable to our lives, since it approaches learning in a linear order, focusing on studying or practising one area until we are ready to move onto the next, and then repeating this process with the next stage in the sequence.
Related to the point just made, the authors argue that the best retrieval practice reflects how we will use the knowledge we retrieve in our lives. Again, this relates to points in earlier chapters about contextualisation. The ‘kind of retrieval practice that proves most effective … reflects what you’ll be doing with the knowledge later’.
Relating what we learn to our lives and other areas of our knowledge significantly helps to consolidate learning. ‘It’s not just what you know’, the authors write, ‘but how you practice what you know that determines how well the learning serves you later’ (p. 57). ‘Practice what you know’ can be interpreted widely: it need not be practically applying learning to some real-world problem – that would be far too limiting for much of the knowledge we have. Putting learning into practice can involve relating what we learn to some other area of our knowledge, or contextualisation.
Here are six questions we might consider.
1. Possible contexts in which massed practice could be an effective learning strategy
The authors argue that massed practice is an ineffective learning strategy. But in this chapter they acknowledge that massed practice has short-term learning benefits, such as gaining knowledge quickly in short-term memory (pp. 47-8).
In light of these benefits, are there some purposes for which massed practice is an effective learning strategy?
For example, consider final revision the day before or morning of an exam: if cramming (the paradigmatic form of massed practice) has short-term benefits, is it a useful learning method at those times?
2. Possible courses in which massed practice could be an effective strategy
The chapter outlines the pervasiveness of massed practice: ‘Almost everywhere you look, you find examples of massed practice’. Examples include summer language boot camps, continuing education seminars condensed over weekends (p. 48), and even the form of mathematics textbooks (p. 53).
Are there cases where massed practice is an effective strategy in a course of learning – perhaps even the dominant strategy?
For example, consider one of the examples given by the authors of massed practice: intensive language courses. An intensive language course using the Berlitz method may be more effective than the same amount of language studied over a year, even for long-term learning.
3. Interleaving multiple subjects
‘Interleaving the practice of two or more subjects or skills is … a more potent alternative to massed practice’ (p. 49). The authors’ example is of various problems in one subject (geometry).
What about interleaving ‘two or more subjects’?
An example is not given. Would interleaving multiple subjects yield the same long-term learning gains?
4. Structuring a scheme of work through interleaving
‘[R]esearch shows unequivocally that mastery and long-term retention are much better if you interleave practice than if you mass it’.
What are the implications of interleaving for structuring a scheme of work?
A potentially useful example is given: ‘spiralling [a] series of exercises that cycle back to key skillsets in a seemingly random sequence that adds layers of context and meaning at each turn’ (p. 50).
5. Motivating students when learning feels more effortful
The authors convincingly argue that we tend to be drawn towards massed practice because we feel the short-term learning gains, and we are drawn away from more effective learning strategies because they require more effort. Connectedly, they note the importance of motivation: since the most effective learning strategies do not feel beneficial for learning in the short-term, it is important that teachers motivate students during the early stages of learning (p. 63).
How can we motivate students during the early stages of learning, when it feels effortful but there are not the same short-term gains we get from massed practice?
6. The difficulty of changing our perception of learning processes
A general conclusion we can draw from Make It Stick so far is that we need to change our perception of learning processes (p. 47): for example, we need to see effortful learning as more effective than learning that requires less effort.
How much can we expect to achieve this within our own classrooms or departments, given the current educational landscape? In order for perceptions to change, do we need culture shifts within entire educational institutions?
The authors put forward ways in which education needs to be reformed to improve learning in light of the research in the book (p. 60).
I put some of these questions to the book’s authors in a recent webinar we hosted, which will be uploaded to the CIRL podcast soon.