Four ways cognitive load theory has changed my teaching

I am going to describe some ways that knowledge of cognitive load theory (CLT) has changed how I teach. Prior to learning about CLT, I used what I have previously termed ‘default teacher led instruction’. I stood at the front and explained things but it was not an optimal form of explicit instruction. On the positive side, I had developed good classroom management over time and, since the mid 2000s, I had implemented some of Dylan Wiliam’s formative assessment techniques. This was, on reflection, an excellent basis for learning about CLT.

I am going to write in the context of my maths teaching because this provides the clearest examples. Maths is also an area that has been heavily targeted in CLT research. However, I have been involved in transferring these ideas to other subjects and have always found such transfer to be complicated but possible – again this mirrors the research. But that discussion is for another day.

1. I don’t read out my slides

I have a PowerPoint for every lesson that acts as my lesson plan. It has a starter activity, lists the homework, states the learning intention, reminds me to take the register, displays any notes and contains all class examples and questions, along with the solutions on subsequent slides.

I print a selection of these slides and hand them to my students. They glue the slides in to their exercise books, annotate them and then answer any questions in their books.

When we get to a slide that presents some theory such as the origin of Euler’s number, I ask the students to read it and I give them ample time to do this before I start talking about the content of the slide.

I do this because of the ‘redundancy effect’ found in CLT: a simultaneous oral and text presentation leads to less comprehension than the text alone. This is probably best understood in terms of dual channel processing and is also a feature of Mayer’s cognitive theory of multimedia learning which is closely related to CLT.

Our working memories effectively have two ‘channels’. One processes visual information and the other processes spoken language. Reading starts off in the first channel with the letters being observed visually. These are then decoded into virtual sounds that are processed in the spoken language channel. If a student is required to process spoken language at the same time as reading then this jams up the spoken language channel. Some students may be able to select either the spoken or the written and pay attention to just one of the sources but this redundant information is of benefit to nobody so I avoid it.

2. Break it down, further

New learning can be fairly transient. Information will quickly disappear from students’ minds without the opportunity to process it.

I used to present a series of examples before I asked students to complete a task. For instance, I might show them how to sketch an exponential curve before reminding them of how to apply index laws. They would then complete an exercise on these problems.

These days, I pause for practice between each individual problem type. So after the graph example, students will complete a graph question and after an index law example, students complete an index law question and so on. Which leads to the next technique.

3. Example-problem pairs

In research into the use of worked examples, the use of example-problem pairs was found to be optimal for learning. A worked example is written on one side of a page with an almost identical question posed on the other side. This way, students can apply the method of the example directly to the question. This minimises extraneous cognitive load and focuses attention on the key features.

I replicate this with my slides: one side has an example and the other has a question.

If we step back a little from CLT then I think example-problem pairs serve a wider purpose. In his review of process-product research, Barak Rosenshine suggests that effective teachers aim for an 80% success rate. This is one way to achieve success and I suspect it is motivating for students.

In the past I think I have gone for transfer too early. After demonstrating a worked example, I have tended to ask slightly different questions, thinking that this will lead to more flexible learning but I probably just caused frustration in students who were struggling.

4. Stop after five minutes

And I’ve come to a much more nuanced understanding of cognitive struggle. If you know little else about CLT then you probably are aware of the idea that too much struggle can overload working memory. However, it’s not just the total amount of cognitive load that matters but the type of load.

Dan Willingham tells an anecdote in ‘Why don’t students like school‘ that has been referenced on many blogs. He writes of a teacher who wants students to learn about the Underground Railroad, the historical system of safe-houses and routes that were used to smuggle slaves out of the south of the U.S. The teacher asks the students to bake biscuits of the kind that the freed slaves would have eaten. Willingham points out this would have caused the student to think about measuring butter and flour rather than the Underground Railroad. Teaching should cause students to think about the right things because ‘memory is the residue of thought’.

Now let me outline a much more subtle example. Students given a maths problem to solve and with no immediate solution strategies to use will engage in means-end analysis. This is a generic problem-solving strategy that we all possess and it involves measuring your current state, evaluating how far you are from the solution state and then deciding which moves may get you closer. This is cognitively demanding to the extent that even if you manage to solve the problem, you might not recall the solution method. You might not actually learn anything from the process; one reason why worked examples beat solving problems in classic worked example studies.

So my advice to students is, “Never spend more than five minutes trying to solve a homework problem.” Five minutes is actually quite a long time. If students don’t recognise a solution pathway quickly then they are likely to start applying means-end analysis. Rather than engaging in worthwhile practice they will learn little and would be better served by moving on to other questions.

“Put a circle around the question,” I explain, “and raise it with me in class or come and see me. I am your teacher and it’s my job to explain how to do it.” I always ask for homework issues at the start of each lesson and spend some time going over them.

Yes, students will have to persist with some non-obvious exam questions but the best way to prepare them for this is to practise lots of different strategies and not to ask them to practise persisting.


No doubt some of you will be thinking that this is all just obvious; that you don’t need cognitive load theory to work this out; that good teachers have always known about these strategies. Maybe they have. I did not.


24 Comments on “Four ways cognitive load theory has changed my teaching”

  1. Carl Badger says:

    Have a question about the reading along with the pupils. I work with 6 and 7 year olds. I try to get to read all the time, sometimes quite difficult texts. I will read the text with the children a couple of times so that they know first of all what the text is saying (the children follow along). I do this as I want the children to have the best reader reading to them and hear what any tricky words might say. I link this to phonetic understanding. I will then allow the children the opportunity to read the text independently before having a go at doing any comprehension etc. Am I creating too much cognitive overload?

    • Greg Ashman says:

      I simply don’t know. The experiments that I am referring to would all involve students who are capable of independently reading the text.

    • Berys Dixon says:

      Way too much overload! For a start don’t give them texts to read for which they don’t have the alphabetic/phonic knowledge.

      • Carl Badger says:

        They do.They are beginning to become very good readers. Some have made 3 years progress since September. I am not giving the children War and peace to read just texts that are slightly beyond them. They have made this progress as we have a very good reading programme that runs alongside what i do in other subjects. I refer to phonetic understanding because I want them to see the relevance of the phonic programme they are involved in.

        I’m not sure where I said that they have no alphabetical or phonetic knowledge?

    • kesheck says:

      If this is of any help – in his book, “Raising Kids Who Read,” Dan Willingham wrote that trying to have students work on decoding and comprehension at the same time would overload working memory. It seems to me like you’re trying to reduce that cognitive load, so that’s good.

      I don’t know the answer to this question, but I’ll ask it anyway – would it be somewhat better to choose words from the text that you think your students don’t know how to decode teach those first? Then read the entire text for comprehension?

      Someone needs to do a study on this! 🙂

      • Carl says:

        Thanks for your positive response.

        What you have suggested is something that I want to look at next, so you have helped inform what I am going to do next. I wanted to link it to the tier 2 words so that the children understand and can say any words that they may have trouble saying or understand. You are absolutely spot on though about the study with younger children.

    • xiousgeonz says:

      I don’t think this is adding to the load — I think it’s helping reduce it. (I work with older students with reading difficulties and many of them would be in much better shape had what you describe been their experience.) This is assuming there is some instruction in that phonetic understanding and they’re not expected to absorb it (many will, but there’s a chunk whose brains don’t work that way).

  2. Alex Brown says:

    I have also been limiting homework time for the same reasons.

    My current school uses Google Classroom, which is almost useless in class time as it is a distraction from my teaching, but as a a means for collecting independent student work it is useful, as you can set a Google Question (with marks and/or feedback) and you can access remotely before the next class.

    Using the principles of spaced and retrieval practice, I tell kids and parents (who can now ‘help’ monitor completion without expert subject knowledge) to complete the question – always the same process modelled and practised in class – in no more than 10 mins. A poor response under timed conditions is excellent formative assessment; it lets me know exactly what processes must be reviewed, and better yet, I break down a successful student example in the next class in the review of prior learning. I get more examples and students get a bit of public praise.

    It’s been win-win-win. Students love that there is less overall homework, parents are happy that they are contributing and their child is developing organisational habits, and, I’m getting excellent data on student understanding and application of knowledge frequently and cumulatively.

  3. Linda greaves says:

    This is really interesting. I do 2,3 and 4, but not 1. Could you provide an explicit example of how this works in practice?

  4. paulgmoss says:

    A really informative post. Thanks Greg

  5. Mike says:

    Number 1 is a goodie. Reminds me of endless inservices with useless guest speakers simply reciting their PowerPoints, often with next to no elaboration. (The sequel of this on one occasion was a witty and very cynical colleague of mine remarking “I can’t see how anyone ever learned anything before PowerPoint.”)

    Seriously though, I hadn’t heard of the “redundancy effect”, but in my experience it’s spot on. These days I’m very careful to design my PPs so that there will be no need for reciting.

    Number 2 is also spot on. As a language teacher, introducing a new tense (in a Romance or Germanic language, at least) often involves a whole new series of endings to be mastered, and I’m always disappointed to find in some textbooks that the exercises appended to the grammatical information feature a mix of tenses, or perhaps a different challenging grammatical structure within the sentence(s). This often proves too disconcerting.

    A good theme song for teachers in this respect:

    WIth number 4, this might differ a little from subject to subject, I feel. And it also seems to me that the maximum struggle time could be stretched a little for senior students – not sure whether the research has anything to say about this?

  6. In research into the use of worked examples, the use of example-problem pairs was found to be optimal for learning.

    I’d know that example-problem pairs were great at reducing extrinsic load and really good instructional activities, but I didn’t know they were ‘optimal.’ Could you point me to a citation for that?

    (I’ve seen studies where example-problem pairs are compared to examples alone, or problems alone. But that hardly exhausts the instructional universe.)

  7. kesheck says:

    Great post! I can definitely see how your Example-Problems pairs could work with teaching mechanics, usage, and grammar in writing. Thanks!

  8. Bret Biornstad says:

    Can you point me in the direction to an example of your first point, specifically a sample batch of slides? Thank you.

  9. […] Four ways cognitive load theory has changed my teaching | Filling the pail […]

  10. xiousgeonz says:

    If you look at materials and lessons out there in the world you’ll see that most people don’t do what you describe… thanks for the eloquent, elegant summary.

  11. […] Start with model answers. @greg_ashman recommends modelling followed by near identical problems for students to complete (here). […]

  12. xiousgeonz says:

    One serious hazard I see with this, though, is students learning to successfully do each pieces part and not seeing connections and bigger ideas.

  13. […] Four ways cognitive load theory has changed by teaching, by Greg […]

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