No pain, no gain – on desirable difficulties

Hilly Drok
desirable difficulties

Imagine you teach chemistry and want your students to learn the periodic table so that they can analyse chemical behaviour more easily. You therefore want them to memorise the periodic table. However, you also know that students are not going to do this on their own, so you motivate them by giving them a test.

The students learn the system by heart, almost all achieve a pass and in the next lesson series, you want to build on this knowledge… but suddenly they have all forgotten it! Meaning, you can start again … from scratch.

Extremely frustrating for you as a teacher – because this way you can’t progress in your lessons – and also very inconvenient for the students – because they lose valuable lesson time and never become independent in their learning this way.

Your students should have used more effective learning strategies: desirable difficulties. In this blog, I will outline what desirable difficulties are, why they are so important, what they can look like, how they are used in formative action and how they can contribute to self-regulated learning. In a subsequent blog, I will give a practical interpretation of how to help your students use these effective learning strategies in their own learning.


Ineffective learning strategies

Many students apply ineffective learning strategies when learning: techniques such as cramming or rereading that in the short term ensure that they have the knowledge in their heads, but do not ensure long-term mastery. While we teachers are all about that long-term mastery: we assume that we can build on the knowledge we have previously imparted to our students, and we naturally wish the same for our students.

Not infrequently, we are disappointed. Annoying for us, but quite disastrous for our pupils, because ultimately they will also have to shape their own learning well and for that, first of all, an important knowledge base is needed and, on top of that, it is necessary to master the right strategies, to ensure that they can also evaluate their own learning well and adjust their learning accordingly.


What are desirable difficulties

Desirable difficulties – introduced by Bjork[1] are indispensable in effective learning. Desirable difficulties are learning techniques that are not necessarily comfortable, but are enormously effective and ensure long-term mastery and learning. Examples of desirable difficulties are retrieval practice (retrieving information from long-term memory), spaced practice, and interleaved practice.

Active retrieval

So in retrieval practice, which translates as active retrieval, you ensure that students themselves actively retrieve information from their long-term memory, for example by having them review words or recall what was covered in the previous lesson.

Spaced practice

When using spaced practice, make sure there is time between different exercises on the same topic. For example, by presenting students with a number of tasks on Pythagorean theorem, then letting the topic rest for a while and having them complete tasks on Pythagorean theorem again a week later.

This gives students a chance to almost forget learning material. When they then recall the material from their long-term memory, it sticks all the better. This can also be seen in Ebbinghaus‘ well-known Forget curve. As a result, Bjork and Bjork call forgetting the friend of learning[2] (see this video). So it is better to have students practise on something three times for half an hour than dipping in for one session of an hour and a half.

Varied practice

Varied practice means alternating different topics, rather than presenting them in isolation. So instead of first giving ten exercises on the present tense verb, then ten exercises on the past tense verb and then ten exercises on the past participle, mix them up. This way, students will get frustrated at first, because it is harder to think of which rule to apply when. But once they master it, they will have mastered it more fully.


Formative action and desirable difficulties

An important basic principle in formative practice is that it is about mastering rather than covering(see also this blog). If the main goal in teaching is to finish the book or the study guide, without keeping in mind whether that pace and level of difficulty suits the class you are teaching, then you are in fact just throwing knowledge over the fence.

The fact that all the material has been covered (or thrown!) does not mean that mastery is taking place among pupils! Of course, you want pupils to acquire knowledge and skills that will benefit them throughout their lives. That is why it is also important to use desirable difficulties: that way, you work towards long-term mastery.


Retrieval and spaced practice in formative action

When you are doing formative practice, you are undeniably using desirable difficulties, such as active retrieval (retrieval practice) and spaced practice.

Indeed, in step 2 (thinkand generate) of the process of formative action, learners must all retrieve knowledge from their own minds, without aids and without consultation. The active retrieval of information (retrieval practice) further solidifies knowledge schemas in long-term memory.

The effect achieved with retrieval practice is also called the test-effect. By capitalising on the test effect, you ensure, as it were, that the knowledge is better perpetuated and also more agile to use, because the ‘paths’ in the brain on the way to the knowledge become more passable.

In step 5 (verify, reflect & predict), you will perform another retrieval practice, and depending on your design, you might also perform spaced practice here, if you choose to perform step 5 just a little later in the learning process to make the best use of the forgetting curve.

Transformative feedback as desirable difficulty

Transformative feedback, which involves learner thinking and is more work for the receiver than the giver, also causes learners to have to be more active in processing feedback and think more.

You can do this, for instance, by not writing all kinds of instructions on the students’ work, but letting them ask you a feedback question themselves: what are they still in doubt about and would they like feedback on? Or by indicating to a student: in your first paragraph, three verb forms are misspelled, look up which ones. In this way, the student is thinking, which deepens understanding.

This is another example of desirable difficulty: students have to be actively engaged, it is harder for them than feedback handed to them on a silver platter, and it may take them longer to master the material, but they learn more in the long run.


Paradox of desirable difficulties

Students will not, of their own accord, easily choose to use desirable difficulties in their learning process. For one thing, it doesn’t feel comfortable at all to have to recall something from memory that you can just about reach, or start on another topic when you’ve barely just understood the first one.

Many students prefer comfortable learning strategies to desirable difficulties[3] – even if the teacher tells them time and again that these are less effective. It just feels safer to mark the important text or read it over again than to quiz yourself or explain it to the neighbour.

In addition, it is also true that desirable difficulties in the short term yield less learning gain. If you offer the tasks on the different verb forms in a blocked fashion (first ten tasks on person form present tense, then ten on person form past tense, finally ten on past participle), students will undoubtedly answer the tenth question correctly and seem to master it immediately.

If all the questions on the different verb forms are mixed up, they might not answer the tenth question on the person present tense correctly. Students will soon think this makes it better for them to avoid desirable difficulties, when in fact it confuses learning and performance.


Learning and performance

Indeed, deep learning is different from being able to perform in a single moment. Imagine, someone asks you to memorise a login code for a moment, until she finds her phone and can store it in there. The best thing you can do then is to keep repeating that login code over and over again. In effect, you are mashing it.

If she asks you to repeat it after three minutes, you do so effortlessly. However, if she asks you again two months later what that code was, you won’t remember; you were able to perform well in that one moment, but no learning took place.

If you open a new checking account, and you get a new PIN, you will have to recall that code from your long-term memory at different points in time. You might have to cheat at first, but as you have to dig up that code from your memory over different periods in time (depending on your spending pattern), at some point you won’t even have to actively think about what your PIN was again: learning has taken place.


Effective learning vs short-term performance: an example

It works the same way with learning lessons in school. Suppose you want students to increase their vocabulary in French so that they can more easily hold conversations in French on different topics, you can give your students a test that covers different words.

As long as they are not properly supervised, students will most likely choose to cram in the words just before the test and probably get a good grade. However, if they then have to apply these words to speaking six months later, they will have completely forgotten them and you can start all over again.

It is more effective to regularly bring those words back into lessons, by actively retrieving them from students’ memories. In this way, deep-rooted understanding will occur, which will also allow students to use this knowledge in an agile way, i.e. in different situations and contexts.


Undesirable difficulties

So effective learning actually only takes place when it hurts a little, but that does not mean that every difficulty in learning immediately leads to better understanding. When a learner has too little prior knowledge or so much new knowledge comes at a learner that they are cognitively overloaded, they also certainly experience difficulties, but no learning takes place in this process.

It is therefore important that the difficulties do lead to deeper understanding or perpetuation of the understanding. This is only possible if the learner does manage to link it to existing prior knowledge[4] . So the requested thing must be possible but slightly beyond the learner’s immediate reach.


Determining whether a difficulty is undesirable

It is very difficult for a learner to determine when it is a desirable difficulty (recalling something you were told a week ago feels uncomfortable and also less effective than just reading it back in your notes, but makes a lot of sense) or an undesirable difficulty (trying to see a connection between three complicated concepts that you actually didn’t understand very well all to begin with just won’t work and is also then also not useful).

Two important conditions for desirable difficulties are that pupils 1) do have to think harder about the material but 2) that the desired result is achieved in the end. As a teacher, it is therefore important to always check whether pupils are being challenged but you are not asking the impossible of them.


Benefits of desirable difficulties

On balance, it is quite understandable that students often choose easy learning strategies. It hurts less and, moreover, it provides them with what they are looking for in the short term: enough mastery to pass the test the next day, for example.

Yet there are also considerable advantages for students to use desirable difficulties during their learning. The main benefit is deep-rooted understanding. At first glance, it does not necessarily seem necessary for learners to memorise knowledge for longer than the test; their goal is often a passing score anyway.

However, if they make sure the knowledge is in long-term memory, then they make the subsequent learning easier for themselves. They have created new prior knowledge, to which it is even easier to attach new knowledge and so their knowledge network only expands further. And of course: the more you learn, the more fun learning becomes.


Desirable difficulties and self-regulated learning

In addition, making desirable difficulties explicit also contributes to better self-regulated learning. Some students tend to use quantity cues (as Anique de Bruin calls them, for example in this podcast) to determine whether they have learnt well enough: “I studied for three hours, so now I must know it well enough” or “my summary covered six A4s, so I learnt well”. Needless to say, these are not the right conclusions.


Incorrect causal attribution

Even after learning, learners who have little understanding often misattribute their comprehension: for example, they attribute their success or failure to external factors beyond their control or to factors that say nothing about their mastery (‘it’s a short text, so I think I get it’).

When students apply desirable difficulties in their learning, they have a better grip on their actual mastery. They can then rely on quality cues: ‘I can clearly explain all the connections between the different concepts, so now I understand it well enough.’


Grip on own learning

As learners improve their attributions, they can also assess themselves more adequately. So they have a better view of their learning process, gain a better knowledge of what is still needed in that learning process. Because they test themselves they know better where the gaps in their knowledge are, and when they have understood it well enough. They thus get a better grip on their learning process.


Improved self-efficacy

It is plausible that when pupils have more control over their learning process, their confidence in their own abilities will also increase. However, because this has never been researched, so there is no scientific evidence on this. We do know from research that perceived learning (how much pupils think they learn from a strategy) increases if they use that particular desirable difficulty more often[5] .

Furthermore, desirable difficulty leads to greater success in the long run. It takes a while for students to experience this success, because at first, it mostly feels very uncomfortable and seems like they will never master it.

However, if they persevere, with help from their teacher, they will find that they master the subject matter better than if they do not use desirable difficulties. We know from studies that when you experience success that you do not externally attribute, you feel that you can handle it. So it could very well be that desirable difficulties also contribute to increased self-confidence[6] .


Self-regulatory capacity

Moreover, it is known from research by Pintrich and de Groot that learners who believe they are capable, which they experience after using desirable difficulties, use cognitive strategies more often, and are more self-regulated in the sense that they make more use of metacognitive strategies[7] . Moreover, these learners are more likely to persevere when faced with difficult or uninteresting tasks.


But beware!

We would like pupils to be in charge of their learning. Desirable difficulties can help pupils do this, and in this way pupils can learn in a more self-regulated way. Yet, as a teacher, you cannot expect this from pupils too early in the learning process.

A precondition for being in charge of your own learning process is to have sufficient knowledge of the content: you cannot assess whether or not you have mastered something if you do not know exactly what the task involves. Therefore, in addition to sufficient content knowledge, sufficient quality awareness is also essential.

Only when students have a quality sense of what strong work should meet, and when they are able to do so, can they judge well enough whether they meet it. So keep in mind differences between beginners and experts.


Take-away messages

  • Desirable difficulties help students in their learning. However, they will not start applying them on their own accord because they feel ineffective and uncomfortable. It is therefore important that you, as a teacher, have sufficient knowledge of which learning strategies are effective, use them and instil them in your teaching;
  • Pupils are beginners and therefore cannot yet grasp what is expected of them and when they have reached sufficient mastery. You can help them master the knowledge properly by using desirable difficulties in your teaching;
  • When you act formatively, you make use of desirable difficulties. So for optimal mastery, make sure you use formative action as much as possible;
  • Only when students have gained a deep understanding of how to learn effectively are they also capable of self-regulated learning. So through desirable difficulties, give your learners the opportunity to create deep understanding. By subtitling the desirable difficulties, you also ensure that learners are able to self-regulate learning, as it also gives them the tools to take charge of their own learning.

How to ensure that you help students take ownership of desirable difficulties in their own learning, I describe in this blog.




  1. Bjork, R.A. (1994a). Memory and metamemory considerations in the training of human beings. In J. Metcalfe and A. Shimamura (Eds.),
  2. Bjork, R., & Bjork, E., (2019). Forgetting as the friend of learning: implications for teaching and self-regulatedlearning. Advances in Physiology Education, 43, 164-167.
  3. Pearce, J. & Moore, I. (2024). Bjork & Bjork’s Desirable Difficulties in Action. London: John Catt Bookshop
  4. Bjork, R. A., & Bjork, E. L. (2020). Desirable difficulties in theory and practice. Journal of Applied Research in Memory and Cognition, 9(4), 475-479.
  5. Onan, E., Biwer, F., Abel, R. et al. Optimizing self-organized study orders: combining refutations and metacognitive prompts improves the use of interleaved practice. npj Sci. Learn. 9, 33 (2024).
  6. Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioural change. Psychological Review, 84(2), 191-215.
  7. Pintrich, P. R., & De Groot, E. V. (1990). Motivational and self-regulated learning components of classroom academic performance. Journal of Educational Psychology, 82(1), 33-40.



  • Hilly Drok

    Hilly Drok is a trainer, educational consultant and director at The Formative Action School. She also coordinates the Formative Action course for School Experts. She has been a Dutch teacher for 14 years and pioneered the implementation process of formative action at her high school. She is currently working on the topic of self-regulation.

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  • Hilly Drok

    Hilly Drok is a trainer, educational consultant and director at The Formative Action School. She also coordinates the Formative Action course for School Experts. She has been a Dutch teacher for 14 years and pioneered the implementation process of formative action at her high school. She is currently working on the topic of self-regulation.

    View all posts

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