This is the fourth in a series of blogposts 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 focuses on the fourth chapter, ‘Embrace Difficulties’. For our blogposts on previous chapters, see our blog. Several of the key terms discussed in what follows are defined in those blogposts.
We recently hosted a webinar panel discussion with the book’s authors. This is available on our podcast.
Jonathan Beale, Researcher-in-Residence, CIRL
This chapter focuses on the benefits of difficulties for teaching and learning, especially ‘desirable difficulties’ (‘DD’): ‘Short-term impediments that make for stronger learning’ (p. 68). This chapter focuses on explaining what DD are and why they are effective.
The principal argument of Make It Stick isthat certain learning strategies are counterintuitive yet effective. DD are another example. The key idea behind DD is that making a task or skill more difficult can lead to more effective learning and retention of the task or skill (pp. 266-7).
The authors connect DD with some of the learning strategies discussed so far to illustrate why DD are effective. For example, spaced practice, interleaving and mixed practice are all learning strategies that require more effort and in impede learning in the short-term. In this sense, they are difficulties. But since they are more effective for stronger learning in the long-term,they are desirable. These strategies ‘require more effort and slow down apparent gains’ and so ‘will feel less productive at the time’, but they ‘will more than compensate for that by making the learning stronger, precise, and enduring’ (p. 81).
The concept of a ‘desirable difficulty’ was coined by the psychologists Elizabeth and Robert Bjork in 1992 (p. 69). They use evidence from psychology to show that certain learning processes are difficult but beneficial for learning (and in this sense desirable) because ‘they trigger encoding and retrieval practices that support learning, comprehension, and remembering’.
The benefits of forgetting
The authors of Make It Stick describe a ‘paradox’ at the core of DD: ‘the more effort required to retrieve (or, in effect, relearn) something, the better you learn it’. Effortful retrieval is an example of DD: ‘the easier knowledge or a skill is for you to retrieve, the less your retrieval practice will benefit your retention … Conversely, the more effort you have to expend to retrieve …, the more the practice of retrieval will entrench it’ (p. 79).
This means that it can be beneficial to allow yourself to forget, to a certain degree, what you have learned: ‘the more you’ve forgotten about a topic, the more effective relearning will be in shaping your permanent knowledge’ (p. 82).
How much forgetting should we allow to set in? As we saw in the discussion of spaced practice in our previous blogpost on the book, only a little: while a little forgetting has the advantage that retrieval requires greater effort and leads to better long-term recall, ‘you do not want so much forgetting that retrieval essentially involves relearning the material’ (p. 63). Spaced practice and interleaving support this process: ‘when you let the memory recede a little, for example by spacing or interleaving the practice, retrieval is harder … but your learning is deeper and you will retrieve it more easily in the future’ (p. 75).
These points from the authors about learning and long-term memory either draw attention to an inconsistency or a common problem we face when pursuing the strategies most beneficial for teaching and learning. The authors claim both that ‘the more you’ve forgotten about a topic, the more effective relearning will be in shaping your permanent knowledge’ (p. 82) and that ‘you do not want so much forgetting that retrieval essentially involves relearning the material’ (p. 63). On one interpretation, these claims are inconsistent. On another, these claims draw attention to the common problem of having to strike a balance between (i) time and (ii) pursuing the strategies most beneficial for learning. If the claim is that allowing yourself to forget most or even all of your learning about a topic or skill such that you need to re-learn it all over again results in greater long-term learning, then this may well be a highly effective learning strategy for long-term retention of knowledge (ii), but it would be extremely time-consuming to re-learn a topic or skill all over again (i). Moreover, it may be frustrating and tiresome both for the teacher and learner.
So, if we are to avoid the interpretation that these claims are simply inconsistent, we nonetheless need to strike a more sensible balance between (i) and (ii). The advice concerning spaced practice in the previous blogpost is probably best to pursue: allow a little forgetting to set in, but not so much that students have to re-learn material and the teacher has to re-teach it (p. 63).
The previous points illustrate a way in which forgetting what has been learned can be advantageous for learning. There is also a way in which forgetting is essential for new learning. Some ‘forgetting is often essential for new learning’, the authors write, because some areas of learning are disadvantageous to learning progress when applied in other contexts (p. 77). Consider for example moving from using a PC to a Mac after only ever using a PC, or from a Blackberry to an iPhone, or from using a manual gear car to an automatic. There are things one needs to unlearn in order to function well performing the same tasks – using a computer, using a phone, driving a car – in a new environment with new tools (pp. 77-8).
For learning to be retained long-term, we need to do two things:
1. ‘as we recode and consolidate new material from short-term memory into long-term memory, we must anchor it there securely’;
2. ‘we must associate the material with a diverse set of cues that will make us adept at recalling the knowledge later’ (p. 75).
These ‘cues’ are known as retrieval cues and are discussed below.
We must also practice and apply what we learn (p. 75). This is related to a point discussed in previous blogposts, contextualisation:the process of showing the learner the significance of what they are learning in their lives – in other words, making learning matter for them. The authors write,
‘Knowledge, skills and experiences that are vivid and hold significance, and those that are periodically practiced, stay with us’ (p. 76).
‘Knowledge is more durable if it’s deeply entrenched, meaning that you have firmly and thoroughly comprehended a concept, it has practical importance or keen emotional weight in your life, and it is connected with other knowledge’ (p. 77).
This process of forgetting what has been learned involves forgetting ‘retrieval cues’ or replacing those cues with new ones (p. 78). A retrieval cue is a way of cueing something from memory (p. 75). For example, when we change from driving manual to automatic, we have to ignore the retrieval cue we have learned which leads us to depress the accelerator, put our foot on the clutch and change gear when the sound and feel of the revs reaches a certain point. We of course do not forget this entirely; but we ‘forget’ this retrieval cue in the sense that we no longer pay attention to it. The process of not paying attention should become unconscious and non-intentional: while in the early stages of driving an automatic for the first time, you have to intentionally choose to not focus on the retrieval cues emerging as the revs reach a certain point, through practice, eventually these cues will just be ignored without you having to think about it.
Our retrieval capacity is very limited. This is for evolutionary reasons: if our minds presented us with huge amounts of information whenever we wanted to retrieve knowledge, we would be bombarded with too many memories to sift through to engage in thought processes efficiently, such as decision-making. For example, if we are trying to remember how to make a Christmas pudding and our minds present us with memories of every meal we have ever made, it would take a huge amount of time to sift through the memories and find the relevant information.
While our working memory and retrieval capacity are very limited, our long-term memory is not. Retrieval cues are important and useful for retrieving knowledge from long-term memory. When we forget something, it’s often our retrieval cues that are forgotten, rather than the knowledge itself: ‘It’s not the knowledge itself that has been forgotten, but the cues that enable you to find and retrieve it’ (p. 77). The authors recommend using retrieval cues to enhance retrieval (p. 75). This involves creating cues that relate what we are learning to what we already know. Using retrieval cues in this way helps us to use utilise more of our knowledge: ‘There’s virtually no limit to how much learning we can remember as long as we relate it to what we already know’ (p. 76).
Examples of desirable difficulties
‘Interference’ is a counterintuitive strategy where learning is interfered with in such a way that while the interference is unwelcome, it is beneficial for learning (p. 86). The authors put forward the following examples of interference:
‘[W]hen text on a page is slightly out of focus or presented in a font that is a little difficult to decipher, people recall the content better’.
‘[W]hen the outline of a lecture proceeds in a different order from the textbook passage, the effort to discern the main ideas and reconcile the discrepancy produces better recall of the content’ (p. 87).
Interference can ‘disrupt fluency’, which can make ‘the learner work harder to construct an interpretation that makes sense’, because it requires more effort. This is an example of ‘active learning’: where ‘students engage in higher-order thinking tasks rather than passively receiving knowledge conferred by others (p. 87).
Carol Dweck’s influential work on mindset is put forward in this chapter as an example of a learning strategy that involves DD (pp. 92-3). Dweck’s worl suggests that we tend to adopt two types of mindset: ‘growth’ or ‘fixed’. A fixed mindset involves beliefs that abilities are fixed; a growth mindset involves beliefs that abilities can develop. Students with a fixed mindset tend to believe that their abilities cannot be changed. Students with a growth mindset tend to believe that with hard work and effort, they can improve. Encouraging a growth mindset involves replacing students’ beliefs that abilities are fixed with beliefs that abilities can develop.
Adopting a growth mindset involves embracing errors and seeing failures as opportunities for growth – in other words, seeing failures as desirable difficulties. Adopting a growth mindset has many educational benefits, particularly for character education, in the development of character skills such as resilience. In this chapter, the authors also highlight its benefits for character education: ‘people who are taught that learning is a struggle that often involves making errors will go on to exhibit a greater propensity to tackle tough challenges and will tend to see mistakes not as failures but as lessons and turning points along the path to mastery’ (p. 91). They also identify ways in which errors can be beneficial for learning: ‘Even strategies that are highly likely to result in errors, like asking someone to try to solve a problem before being shown how to do it, produce stronger learning and retention of the correct information than more passive learning strategies, provided there is corrective feedback’ (p. 91). The authors discuss two fascinating events focused on the benefits of embracing failure for learning: the Paris ‘Festival of Errors’ in 2010 and ‘FailCon’ in San Francisco, an annual one-day conference which started in 2009 (p. 93). (For more on growth mindset, see this CIRL blogpost.)
Another examples of a learning strategy that involves DD discussed in this chapter is K. Anders Ericsson’s influential work on ‘deliberate practice’ (pp. 92-3). Deliberate practice is a systematic method of effortful, highly focused, goal-oriented practice which aims at improving performance. It is sometimes described as ‘intentional engagement in skill-based learning’.
The concept was coined and developed in the 1970s by Ericsson, former Professor of Psychology at Florida State University and a renowned expert on the psychology of expertise and performance. In a 2007 article in Harvard Business Review on deliberate practice and expertise, Ericsson, Michael Prietula and Edward Cokely write the following:
‘It will take you at least a decade to achieve expertise, and you will need to invest that time wisely, by engaging in “deliberate” practice – practice that focuses on tasks beyond your current level of competence and comfort’.
This involves many processes which are undesirable but effective for learning, such as intense focus; regular repetition; sustained effort; and thousands of hours of practice. (For more on deliberate practice, see this CIRL blogpost.)
If a learner lacks sufficient knowledge or skills to be able to gain learning benefits from difficult learning processes, such as the greater effort required from learners when engaging in spaced practice, interleaving and mixed practice, the difficulties are not desirable – they are undesirable.
Undesirable difficulties are ‘impediments [to learning] that you cannot overcome’ (p. 99). Bjork & Bjork define this term as follows:
‘If … the learner does not have the background knowledge or skills to respond to [learning strategies] successfully, they become undesirable difficulties’.
‘To be desirable, a difficulty must be something learner can overcome through increased effort’ (p. 99). The alternative is an undesirable difficulty.
An example of an undesirable difficulty is anxiety while taking a test (p. 92). Evidence from psychology suggests that fear of making errors when taking tests can cause students to perform worse, because the fear takes up ‘a significant portion of their working memory capacity’ (p. 91). This undesirable ‘difficulty can create feelings of incompetence that engender anxiety, which in turn disrupts learning’ (p. 92).
Here are four questions we might consider.
1. What makes a difficulty desirable or undesirable?
Some difficulties depend on context, as the authors note. For example, having someone whisper in your ears as you read aloud would be beneficial if you are training to become a newsreader, but not training to be a conference speaker (p. 99). Cases such as these give rise to the question, what makes a difficulty desirable or undesirable?
The authors note that the research on this is currently limited. Empirical studies in cognitive science show that ‘testing, spacing, interleaving, variation, generation, and certain kinds of contextual interference lead to stronger learning and retention’. Beyond this, they write, we only ‘have an intuitive sense of what kinds of difficulties are undesirable but, for lack of the needed research, we cannot yet be definitive’ (p. 98).
2. Balancing high stakes and low stakes
The authors recommend and give examples of learning strategies that are high stakes, such as training for parachute jumps and training to become a surgeon (pp. 67-74). They use these training regimes to illustrate the effectiveness of several learning strategies in real-world examples, including the point that it is important to make learning matter – that is, we learn better when we see the importance its application plays in our lives. These examples – training for parachute jumps and training to perform surgery – are of learning processes with extremely high stakes. Yet throughout the book so far, the authors have emphasised the importance of regular, low stakes assessment, such as regular formative assessment through low stake quizzes.
How do we make learning anywhere near as high stakes as the authors recommend, while maintaining regular, low stakes assessment?
Consider the concept of ‘interference’ alongside other advice given in the book so far, such as where the authors argued that there are issues with making explanations too clear, because this can make learning less effortful: ‘When [students] hear a lecture or read a text that is a paragon of clarity, the ease with which they follow the argument gives them the feeling that they already know it and don’t need to study it … [but] when put to the test, they find they cannot recall the critical ideas or apply them …’ (p. 17). In this chapter, they have argued that there can be learning benefits to presenting teaching materials in less clear fonts, because it causes students to work harder to decipher what is written and thereby focus more on the material.
What are the pedagogical implications of these points? E.g., should we make our teaching materials in less clear fonts? Should we not try to make explanations as clear as possible?
The more general question here is: Is there a way of coherently incorporating such evidence and suggested methods into teaching practice?
4. Problem-solving without knowing the method
The authors argue that it is beneficial for learning for students to attempt to solve problems without being shown how to solve them: ‘When you’re asked to struggle with solving a problem before being shown how to solve it, the subsequent solution is better learned and more durably remembered’ (p. 86).
How far should we take this, in terms of the extent to which we teach students how to go about solving problems before they are tasked with trying to solve problems themselves? Should we teach them any steps in the relevant method to solve a question at hand at all, or is it beneficial that they try to figure out even the most basic methodological steps themselves?
We may return to these questions in future blogposts.
 See R. A. Bjork & E. L. Bjork, ‘A new theory of disuse and an old theory of stimulus fluctuation’, in A. F. Healy, S. M. Kosslyn & R. M. Shiffrin (eds.), From Learning Processes to Cognitive Processes: Essays in Honor of William K. Estes (vol. 2, pp. 35-67) (Hillsdale, NJ: Erlbaum, 1992). In that article, Bjork & Bjork coin the phrase ‘desirable difficulties in learning’ (Make It Stick, pp. 266-7, n. 2).
 E. L. Bjork & R. A. Bjork, ‘Making Things Hard on Yourself, But in a Good Way: Creating Desirable Difficulties to Enhance Learning’, in M. A. Gernsbacher, R. W. Pew, L. M. Hough and J. R. Pomerantz (eds.), Psychology and the Real World: Essays Illustrating Fundamental Contributions to Society (New York: Worth, 2009, pp. 56-64) (quoted in Make It Stick, p. 98).
 See Duncan R. D. Mascarenhas and Nickolas C. Smith, ‘Developing the performance brain: decision making under pressure’ (Performance Psychology 2011, pp. 245-67): deliberate practice, they write, involves effort and it aims towards improvement of performance (rather than personal enjoyment).
 See ‘deliberate practice’ in Dieter Hackfort, Robert J. Schinke and Bernd Strauss (eds.), Dictionary of Sport Psychology (London: Academic Press, 2019).
 K. Anders Ericsson, Michael J. Prietula and Edward T. Cokely, ‘The Making of an Expert’, Harvard Business Review, 2007. For further reading by Ericsson on deliberate practice, see Ericsson & Robert Pool, Peak: How all of us can achieve extraordinary things (London: Vintage, 2017).
 Bjork & Bjork 2009, quoted in Make It Stick, p. 98.