Principle

Cognitive load theory

Cognitive load theory explains how working memory limits learning, and what teachers can do to reduce unnecessary load so pupils can focus on the thinking that matters.

By Philip BellLast updated 26 May 2026
Evidence
Strong
Subject
Cross-curricular
Key stage
All
Citations
3

Cognitive load theory is the most useful piece of cognitive science a teacher can carry into a Monday morning. It explains why a clear worked example beats a busy task sheet, and why a five-step instruction often beats a one-paragraph instruction.

What it is

Working memory is the bit of memory you use right now to think. It is small, around four items at a time, and it empties fast. Long-term memory is enormous and durable, but the only route in is through working memory.

Cognitive load theory describes three kinds of load on working memory. Intrinsic load is the difficulty of the content itself. Germane load is the productive effort of linking new ideas to existing ones in long-term memory. Extraneous load is everything that consumes attention without contributing, like a confusing layout or a distracting image.

Why it matters

If extraneous load eats up working memory, there is nothing left for germane load to use. Pupils look busy but learn nothing. The clearest evidence comes from worked example research, where novices learn more from studying a worked solution than from solving the equivalent problem themselves.

The EEF cognitive science review and the New South Wales government’s practitioner guide are the two cleanest summaries to share with colleagues.

How to use it

Trim extraneous load from your slides and resources. One idea per slide. Captions next to images rather than legends underneath. Short numbered instructions. Worked examples before independent practice. Worksheets that group related elements close together, called the spatial contiguity effect.

Match the intrinsic load to the pupil. If a class lacks prior knowledge, break the content into smaller chunks before you teach the synthesis.

When not to use it

Cognitive load theory is a lens on instruction, not a curriculum. Do not use it to argue that difficult content should be removed. Difficulty that builds schemas is exactly the difficulty pupils need.

Frayer Model, Visual Keywords, and Graphic Organiser are designed to lower extraneous load by giving pupils a clean structure to think inside.

Evidence

Strong evidence

Foundational theory in instructional design, with four decades of supporting evidence. The worked example effect, the redundancy effect, and the split-attention effect are all robust findings derived from cognitive load theory. Classroom-applicable instructional implications are well evidenced.

Caveats

  • The theory specifies how to design instruction, not what to teach. It is a lens, not a curriculum.
  • Effects differ for novices and experts (the expertise reversal effect). Apply with care to mixed-ability classes.

Populations studied

  • Primary, secondary and higher education learners across maths, science, languages

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Frayer Model
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Visual Keywords
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Graphic Organiser
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Related concepts

Questions teachers ask

What is the difference between the three types of load?
Intrinsic load is the difficulty of the material itself. Germane load is the effort that builds long-term memory. Extraneous load is everything else, like a cluttered slide or unclear instructions. The teacher's job is to keep intrinsic load appropriate and extraneous load as low as possible.
Does cognitive load theory mean I should make everything easier?
No. It means stripping away the load that does not contribute to learning. Pupils still need to think hard about the material that matters.
How do I spot extraneous load in my own lessons?
Look for slides with too much text, instructions that pupils have to keep re-reading, decorative images that distract from the diagram, or activities that require pupils to hold too many things in mind at once.
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Published 26 May 2026. Last reviewed 26 May 2026. Chalk content is reviewed against the evidence at least once a year.