Cognitive Load Theory - 2

Could you be doing these small things that actually make it harder for your learners?

This article continues the series about cognitive load and introduces three more items to add to the list of things we may be doing that actually adds to the cognitive load of our learners.

The essence of cognitive load theory is this: Don’t overload the brain, and people have a better chance of learning

In this article, I want to build on the information shared in the first article to explore extraneous load and the use of images and diagrams.

Use of images brings two things to a crossroad:

1. The way information is presented can increased cognitive load

2. Knowledge that our brains process images more rapidly than text

Research has shown that our brains can get the gist of a visual with one glance, whereas it takes a fraction longer for written language comprehension. So then, the thinking can be that use of images is necessary to reduce cognitive load and aid easier understanding for learners.

It's true that nobody really enjoys presentations with slides full of dense text or sites without images to break up the lines of words. However, just sticking in an image or a diagram is not the simple answer. It's more complicated than that. You see, there are a few circumstances when use of an image will distinctly increase cognitive load.

Firstly, this can occur when the image is not related to the text and is inserted to 'decorate' or make the content look flashy or prettier than just plain old text ...

The two red hearts may be related to each other, but this image has nothing to do with the current point being made in the article text. This is a great example of an image that is actually irrelevant. The mental effort spent trying to figure out any relevance adds to your cognitive load.

Or when the image is an obscure "inside joke" or representation of the presenter's humour that not everyone is likely to "get".

If you enjoy the US Office, you might find this hilarious. If you've never watched an episode or didn't enjoy the series, it's likely this image isn't making the link the author intended to make. An image like this inserted into a presentation can increase mental effort for people trying to figure out what the joke is, and then why this is included/how it's relevant. This is an example of an unfamiliar or abstract icon detracting from the core message.

Instead, include images when they support or can replace the written text.

For example:

Instructions to assemble items from Lego or IKEA are good examples of images being used to replace text and minimise extraneous cognitive load. There's also an argument that they could be attempting to lessen intrinsic load (the inherent complexity of the topic... er, the difficulty of putting together those things!)

Secondly, use of images or diagrams can increase cognitive load if the layout of the diagram forces split attention. Split attention is the cognitive learning phenomenon that happens when people are forced to look back and forth between separate sources of information to make sense of something.

Because the information sources are separated in space (the diagrams on one side of the page and text explanations on the other side), the learner’s brain must waste mental energy searching for and mentally stitching the pieces together. This is the split attention effect.

By contrast, if a diagram is presented like the one below, the brain is not forced to use up valuable memory space just looking back and forth and matching labels to pictures. Instead, it takes in the label as it is positioned on the image.

In this diagram, cognitive load is reduced as we can see exactly the areas of the brain responsible for various functions without having the scan the page to locate any other information.

Thirdly, and somewhat related to the split attention example above, if there is too much clutter in an image or diagram, the brain has to slow down to take in all of the information, make sense of it and attempt to commit to memory. Cognitive load increases with any combination of:

• Confusing visual design

• Excessive text

• Unorganised information

• Distracting graphics that force the brain to waste energy searching for relevant data

We're not even going to try and give a summary explanation of this diagram. Suffice to say, the eye has to dart all over the place and there is some information that is too difficult to untangle.

In particular, generative AI tools excel as creating infographics and diagrams that have high extraneous load. They might look pretty, but typically, they are cluttered with lots of detail crammed in.

Notebook created this infographic summary from the 2026 "Strengthening teaching practices in VET: Research summary" out of NCVER. The prompt was "Create an infographic to summarise the key points from this paper. Ensure the infographic adhere to principles of cognitive load theory". As you can see, even AI wasn't able to adhere to the principles to reduce extraneous load.

Consider whether it takes more time to review the graphic above or simply read a summary such as:

5 Core Strategies to Support Novice Teachers

1. Staged onboarding

2. Help to manage workload

3. Peer support networks

4. Growth-oriented leadership

5. Access to ongoing, targeted PD

4-Stage PD Cycle

1. Identify skill needs

2. Access relevant learning

3. Measure impact

4. Apply new skills

etc.

When designing content for the purpose of assisting learners to take in and retain information, sometimes, plainer is better.

Assist learners by using images that:

• Are relevant to the content and support the message; don't distract from it

• Have integrated labels and that don't create a split attention effect

• Cut the clutter - keep images simple and free from excessive detail

In our next article, we'll look at three more examples of things that add unnecessary mental effort.

This article is AITAS Rating 1

What is the AITAS?

20.10.26

Written by Michelle Charlton who has a degree in Behavioural Science (Psychology) and post-graduate degrees in Learning and Development, Learning Science, and Education Studies.

Image references:

• Lego diagram

• Neuroanatomy: The Basics

• Lobes of the brain

• Bad Infographics: 11 Mistakes You Never Want to Make