Cognitive load theory says working memory can only handle a small amount of new information at once. Give pupils more than that and the extra doesn’t get learned, so it never reaches long-term memory. For your planning, it means pupils should spend their limited attention on the thing you want them to learn and as little as possible on anything else.
That’s the short answer. The rest of this post covers why it matters and what it looks like in an ordinary lesson.
What is cognitive load theory?
Working memory is whatever you’re attending to right now. It’s small, and it shrinks further when you’re tired, worried or having a bad morning. Long-term memory is the opposite. It’s vast, and it holds what we know in organised structures called schemas (think of them as mental folders).
Learning happens when new information is processed in working memory and filed into long-term memory. If working memory is overloaded, the filing doesn’t happen.
Jessica Parker, who presents our course on the subject, has a good picture for this. Think of the brain as a computer: the more tabs you have open, the slower it runs and the louder the fan gets. Now picture a pupil with a new concept, a cluttered slide, an instruction they half heard and a worksheet written in different words. That’s a lot of tabs.
Why does cognitive load matter in the classroom?
You know the moment. You ask “what did we do last lesson?” and get a sea of blank faces, and for a second you wonder whether you taught it at all.
Often that isn’t down to effort or behaviour. Pupils were attending to too many things at once, so the lesson never made it into long-term memory and there’s nothing to retrieve.
Overload feels bad, too. A pupil whose working memory is full feels stressed and lost, and that makes the subject seem harder than it is. Cut the load and they remember more and feel more confident about it.
It’s also easy to forget how new your content is to them. You might have taught this topic so many times you’ve lost count. For your class it’s probably the first time, or the first time in years, and they don’t yet have the schemas that make it feel simple to you.
What are the types of cognitive load?
The theory splits load into kinds. Intrinsic load is the difficulty of the material itself: long division is harder than adding two numbers, whatever you do. Extraneous load comes from how the material is presented, and it does nothing for learning. Think of a confusing layout, unclear instructions, or a fact that’s interesting but beside the point.
You can’t do much about intrinsic load beyond breaking the material into steps and building on what pupils already know. Extraneous load is where you’ll gain most, because you control it, and most of the strategies below are about cutting it.
How do worked examples reduce cognitive load?
A worked example takes the guesswork out of a new task. Pupils don’t have to work out the method and apply it at the same time. They watch it done, then copy it.
It can be very simple:
- Work through a question on the board, saying each step aloud.
- Give pupils a similar question to do by following your steps.
- Once they can, move them on to harder versions with less help.
- Take the scaffolding away when you can see their confidence and understanding growing.
The order matters. Problem-solving and scenario-based tasks are good for deepening understanding, and pupils who elaborate on what they’ve learned are more likely to keep it. But they work best once pupils have the basics. Ask a novice to solve a new kind of problem cold and their working memory goes on searching for a method, leaving little for learning it.
What is dual coding?
Dual coding means giving a spoken explanation at the same time as something visual, like a diagram, a timeline or a labelled picture. Pupils take the information in through two channels at once, and the two support each other.
The timing is the point. Talking through a diagram while pupils look at it works much better than explaining first and handing out the notes afterwards. Showing the same idea in a diagram, then a table, then a sentence gives pupils more ways to rehearse it, and you can teach them to do this themselves when they revise.
One caution. A visual helps when it carries the same idea as your words. A decorative picture, or a slide full of text that you also read aloud, adds load.
Why should you cut non-essential content?
It sounds obvious and it’s easy to forget, because we want lessons to be lively. The interesting aside, the extra example, the fun fact on the slide: each one uses up working memory that pupils needed for the main idea. It can also clutter those mental folders, so the right answer is harder to find later.
Revision lessons are where this bites hardest. If something doesn’t help pupils learn today’s point, leave it out or save it for another time.
How do you connect learning from one lesson to the next?
Cognitive load isn’t only about single lessons. Pupils learn more when each lesson links to the last, because new information then has an existing schema to attach to.
One neat habit is to end a lesson with the start of the next, so they overlap slightly. Use the plenary and the starter to reflect on what’s been covered. Concept maps and knowledge organisers help pupils see how the pieces of a topic fit together. Class discussion, group work and asking pupils to explain their reasoning all give them a chance to process what they know. Small memory cues like mnemonics are worth more than they look.
Is there cognitive load theory CPD for teachers?
Yes. Our online course, Understanding cognitive load theory and its applications to the classroom, is a short introduction you can do at your own pace. It also works as a starting point for a department or whole-staff conversation about planning. You’ll find more on lesson design and pedagogy on our teaching and learning page.
If you want to try one thing this week, take next week’s hardest lesson and go through your slides with one question: does this help pupils learn the main point? Cut what doesn’t, and add a worked example where there isn’t one.
About the course
Jessica Parker’s course explains cognitive load theory in plain terms and turns it into habits for planning and teaching: worked examples and scaffolding, dual coding, cutting non-essential content, and linking lessons so learning builds over time. It’s for teachers, teaching assistants and anyone who plans or supports learning, at any phase. See the cognitive load theory course.