Research School Network: Retrieval Practice: How Hard Should it be? Finding the optimal level of challenge for retrieval practice

Mark Miller is Director of Bradford Research School

Professor Rob Coe poses 3 possible challenges to the effectiveness of retrieval practice in this EEF blog.

• Teachers might generate retrieval questions that focus solely on factual recall (these questions are easier to generate) rather than requiring any higher-order thinking. 
• Questions might be too easy and boost confidence without providing real challenge, which is likely to be a key ingredient for generating the kind of learning hoped for.
• Teachers might allocate too much time to the quizzes, effectively losing the time they need to cover new material.

Last week, we looked at higher order thinking. In this blog, we’ll look at the second idea, by considering the level of difficulty of retrieval.

Desirable Difficulites

So how do we avoid our retrieval being too easy? Well it isn’t simply to make it difficult – we must make it desirably difficult. Robert and Elizabeth Bjork coined the term ​‘desirable difficulty’, which is the counterintuitive idea that in order to learn, we should make things harder.

A good analogy for this is strength training. For me, using a small dumbbell isn’t difficult. But I can’t expect any change. If I lift too much, it’s difficult, but it’s not a desirable difficulty. I will fail and I won’t lift again. So I need to find the weights that are hard but achievable, and therefore it’s a desirable difficulty.

There are a number of different concepts that can be considered desirable difficulties, such as varying conditions, spaced practice, interleaving.

Managing difficulty

There are two main ways that we can fine tune the dial of desirable difficulty with retrieval practice. One is allowing sufficient time for students to forget, before we revisit. This spacing effect makes retrieval more effortful, and therefore more impactful.

The second is the nature of the cues that we use to prompt retrieval. To know that we are going to retrieve something, we need a reminder of what to retrieve. A cue can take a number of forms. It can be very broad like everything I know about mammals, or precise like what is the Latin name for a potato? It could even be a blank piece of paper.

I’m an English teacher so I will ask students to memorise quotations. Depending on the cues I use, retrieval will be more or less effortful. Here are some examples of cues for ​‘Thus with a kiss I die’. 

None of these are the ​‘right’ cue, but show how cues can be designed to be more or less effortful. But perhaps the best approach would ultimately be this one: an exam question.

Which quotations would you use for this essay?

Starting with this extract, explain how far you think Shakespeare presents the inevitability of fate in Romeo and Juliet.
Write about:
• how Shakespeare presents the significance of fate in this extract.
• how Shakespeare presents the significance of fate in the play as a whole.

Not only is the cue suitably difficult, but it is closer to the way that a quotation will ultimately be used, so there is much more utility in remembering the quotation. More likelihood of transfer into the final context.

Here is another example inspired by Tom Sherrington’s ​‘tell the story’ task, which he explains in his comprehensive blog on retrieval practice here. In the first instance, we might have the question, the image and vocabulary to prompt retrieval. Before removing the vocabulary. Then removing the image.

This will look different in different subjects. Over time, we can diminish the cues, making the prompts minimal and the retrieval more effortful. It might start with close retrieval, moving towards the full definition. Eventually, we might end up with a blank piece of paper with minimal prompting. One challenge with minimal cues is ensuring feedback, so make sure that is in place.

For some students, writing out everything they know on a blank sheet of paper may be a daunting task that does not lead to much successful retrieval. It will not be desirably difficult. To increase success, teachers can implement scaffolded retrieval tasks, such as mind maps or graphic organisers. These scaffolds can be removed too. These will be particularly useful for younger students.

We recommend talking to students about the concept of desirable difficulties, otherwise there may be understandably negative responses to the difficulties in class, or they may revert to other approaches when studying at home e.g. reading through notes. They may choose an easier option, or one with an illusion of learning. Also, it’s good to attribute results to strategies – e.g. if students have included knowledge learnt from retrieval activities in a piece of writing, highlight that link.