Cognitive Load Theory and worked examples

Written by: Kiran Arora | Published:
Image: Adobe Stock

Can putting yourselves in your students’ shoes help you to become a better teacher? Former maths teacher turned research manager Kiran Arora reflects on his experience of using Cognitive Load Theory and worked examples to tackle new areas of learning

Cognitive Load Theory (CLT) is becoming more and more popular in education. Suggested to be the “single most important thing for teachers to know” by British educationalist Professor Dylan Wiliam, it has also been cited by Ofsted in its most recent Education Inspection Framework (EIF).

However, despite all the literature and research available on this topic, it was not until I attempted to self-learn an unfamiliar area of mathematics that I started to fully empathise with students who have to learn new topics, and recognised the importance of the way information is presented to them.

So, what is Cognitive Load Theory? First researched by educational psychologist John Sweller, CLT is based around the idea that our “working memory” can only deal with a limited amount of information at one time and that overworking this part can cause “cognitive overload”. Sweller (1988) argues that there are three different types of cognitive load:

  • Intrinsic: The difficulty of the task, determined by prior knowledge or learning.
  • Extraneous: This load is created by the way in which a problem is presented to a learner. De Jong (2010) suggests that “learning is hampered when working memory capacity is exceeded in a learning task”. To be effective teachers, we want to minimise this load.
  • Germane: This aids in learning, as this load results in “resources being devoted to ‘schema’ acquisition”. (Paas, Renkl & Sweller, 2003). Schemas are mental constructs enabling us to understand and categorise information quickly, reducing working memory load.

Striving to learn

While studying for my Master’s in mathematics education at the UCL Institute of Education, I was tasked with learning an unfamiliar area of mathematics, documenting my experience and identifying how the process could help me as a teacher.

I chose to learn how Rivest–Shamir–Adleman (RSA) encryption works and to create my own encryption. RSA is the basis of a cryptosystem used to encrypt and decrypt sensitive messages. It works by using two keys, a “public” key to encrypt information and a “secret” one to decrypt the message. For example, anyone can encrypt details such as a password when logging onto an account, but only the intended recipient can decode the password as they are the only one who has this “secret” key.

I decided to start by throwing myself in at the deep end. I tried to learn the topic by simply looking at the process and learning the formulae, a strategy with which I was previously successful.

However, on this occasion it just did not work for me. The unfamiliarity of the topic was overwhelming and I quickly found myself drowning. There was too much for me to think about and process. I found that I was inundated with information and that this was stopping me from learning the material, theoretically or practically. Sweller would argue that I had given myself an extraneous load. My working memory was stretched and was unable to access or form any schema in my attempt to create an RSA encryption.

This made me realise how intimidating it can be to be introduced to a new topic. As a mathematics teacher, with pressure to complete the required content in time for exams, I was sometimes guilty of teaching new content formally and as quickly as possible.

However, after my encounter with RSA, I appreciated the importance of planning and how the structure of my lessons could help or hinder a learner’s ability to process and retain information.

I had to find a different way of learning...

A new approach

As I reflected on this unusual experience, I realised that I did not understand how the RSA system could or would be useful; how it would work in the “real world”. So I found a video online that broke down RSA encryption with a relatable example that I was able to process.

It was a revelation. Instead of discussing numbers, formulae and algorithms, this video put the information in a way I could simply relate to. The video’s basic explanation reduced my cognitive load – therefore I was able to devote more of my “working memory” to understanding and using the algorithms to create my own public and private keys.

At this point, armed with a new understanding of the system, I decided to look at a worked example of creating an RSA encryption. For this, I used another online video. The constructive use and clear layout of the example made me fully grasp the concept and steps needed. There was no superfluous information, just clear and concise steps to help me understand the process to create my own RSA encryption.

The ‘worked example’ effect

When studying a new topic, I do not think that simply handing out a worked example is enough for students to grasp the topic – and this was reinforced by my personal journey studying RSA encryption.

Ward and Sweller (1990) suggested that in some conditions “worked examples are no more effective, and possibly less effective, than solving problems”. It was not enough for me to have just a worked example to read or watch. The prompts to be engaged in the example helped massively.

Renkl (2005) said that students only get a deep understanding through examples when they:

  • Are self-explanatory.
  • Provide instructive explanations based on simple principles.
  • Aid relationships between different representations.
  • Highlight the relevant content.
  • Isolate meaningful building blocks.

Discovering this information and appreciating it led me to question how I used worked examples in my own teaching practice. Previously, I would simply find a worked example either online or in a textbook, without fully reviewing the information provided, the layout or the complete needs of my students. I was now able to change my approach in the classroom.

An improved teacher

This experience of taking on the role of a student again definitely helped me improve as a teacher. As a result, I made a few key changes to my teaching to make the content easier to access. From then on, I kept in mind three main points when planning and delivering lessons:

The way in which material is presented to students can greatly affect their learning. Starting a new topic from a formal, abstract position can be daunting for students, and a barrier for them to grasp the information.

Cut out inessential information. What I thought might be “interesting” to students as they were learning the topic was probably not, nor was it helping them to learn.

Think about your worked examples and whether they are fit-for-purpose for your lessons.

Although all of this theory can be found in the sources in this article and many beyond, I truly recommend teachers taking on the role of a student more often – it helped me to improve my lessons and teaching. You may even learn something new! 

  • Kiran Arora is a research manager in the Centre for Assessment at the National Foundation for Educational Research (NFER), having previously been a mathematics teacher for seven years. He tweets at @KiranKArora

Further information & research

  • Cognitive load during problem solving: Effects on learning, Sweller, Cognitive Science, Vol 12, 1988:
  • Cognitive load theory, educational research, and instructional design: Some food for thought, De Jong, Instructional Science, Vol 38, 2010:
  • Cognitive load theory and instructional design: Recent developments, Paas, Renkl & Sweller, Educational Psychologist, Vol 38, 2003:
  • Structuring effective worked examples, Ward & Sweller, Cognition and Instruction, Vol 7, 1990.
  • The worked-out examples principle in multimedia learning, Renkl. In The Cambridge Handbook of Multimedia Learning (Mayer, Ed), Cambridge University Press, 2005:
  • Cognitive architecture and instructional design, Sweller, van Merriënboer & Paas, Educational Psychology Review, Vol 10, 1998:

NFER Research Insights

This article was published as part of SecEd’s NFER Research Insights series. A free pdf of the latest Research Insights best practice and advisory articles can be downloaded from the Knowledge Bank section of the SecEd website:


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