What Is Cognitive Overload: How To Spot The Signs And Prevent It In Your Classroom

Cognitive overload is a key concern for all teachers and students. In classrooms and educational settings, experiencing an overwhelming amount of information can impair our understanding, memory retention and ultimately learning. 

When developing our online one to one maths tutoring programmes, cognitive overload is something we’ve kept in mind. From the resources and lesson slides we design to the headsets we send out to schools to deliver the best audio, to the training we provide our tutors – we want to make sure all students can access their tutoring and are in the best position to learn with us.

In this article, we’ll provide a comprehensive exploration of cognitive overload: its impact on learning and memory, and, most importantly, the most effective strategies to overcome this challenge.

What is cognitive overload?

Cognitive overload is a state of mental exhaustion that occurs when learners are faced with an excessive amount of information or demands that exceed the capacity of their working memory. 

This overload can hinder their ability to understand and retain information effectively, making it difficult to transfer knowledge to their long-term memory. When the demands placed on learners’ thinking exceed the limitations of their working memory, it can lead to challenges in learning and reduced performance.

What you need to know about cognitive load theory in order to avoid cognitive overload

Cognitive load theory (CLT) was developed by the educational psychologist John Sweller to explain why some cognitive tasks are more difficult than others.

Cognitive science is the study of how we think, learn, and organise cognitive processes. The structures that are responsible for information processing are referred to as cognitive architecture, which includes our short-term and long-term memory stores.

Our short-term memory has a limited capacity of approximately 5 to 9 pieces of information and a duration of around 30 seconds. More information can be stored if it is grouped into meaningful chunks and the duration can be increased by repeating the information until it is recalled. 

The long-term memory capacity and duration are theoretically limitless; the challenge is being able to successfully encode pieces of information into the long-term memory so that it can be effectively recalled at any given time. 

According to cognitive psychology, information in our long-term memory is stored as schemas of related pieces of information. New information must be added to an existing schema, or a new schema must be created.

Information must be processed by our working memory before it can enter our long-term memory. 

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Types of cognitive load 

There are three types of cognitive load that place demands on our working memory and cognitive architecture: 

1. Intrinsic load

The intrinsic mental effort required to complete a task. It’s determined by the task difficulty and expertise of the learner.

2. Extraneous load

The difficulty of a task due to the way it is presented or explained. 

3. Germane load

The mental effort required for learning to occur, such as schema construction or the automation of a new process.

It is difficult to change the intrinsic load of a task, but it is possible to reduce the extraneous load of a task. This means that students can invest more effort and resources into increasing the germane load.

Cognitive overload examples

Here we explain 5 examples of cognitive load theory in the classroom, in particular, how cognitive overload can occur and practical advice on how to avoid it:

1. Split attention effect

If students are required to split their attention between multiple sources of information or spend mental effort choosing between the sources to decide which one is most important, the extraneous cognitive load of the learning task will increase, leaving less capacity for the germane load which is responsible for learning. 

This can occur when students are taught multiple methods at the same time, such as the sine and cosine rule. If these two new skills are taught in the same lesson, students’ attention will be split between deciding which rule to apply and how to apply the rule. Interleaving topics together for novice learners will also split their attention. 

How to avoid the split attention effect 

The intrinsic load of a task is at its highest during the initial stages of learning a new skill, so it is best to break the skill into smaller components and focus on each one in turn. 

For example, addition fractions could be split into:

  • Finding equivalent fractions.
  • Converting between mixed numbers and improper fractions.
  • Writing fractions into their simplest form.
Third Space Learning lesson reducing cognitive overload
In Third Space Learning’s online one to one intervention, introductory slides break learning goals into smaller components to recap prior learning and build on it. 

2. Modality effect 

The extraneous cognitive load of a task increases if students need to process multiple pieces of information in the same component in the working memory. 

For example, it is very difficult for students to read text and listen to their teacher at the same time as both sources of information are processed in the phonological loop. 

When solving simultaneous equations, teachers will often explain each step of their working as they write it on the board. It can be difficult for students to process the method, especially if they are also trying to copy it into their books. 

How to avoid the modality effect

The ‘silent teacher’ approach involves writing on the board in silence and not speaking until students have studied each step. This approach will relieve pressure on students’ working memory, reduce the risk of cognitive overload, and enhance students’ learning experience. 

Alternatively, the teacher can provide worked examples for pupils to study in silence at the start of a lesson before asking questions about what is happening at each line of work. 

The modality effect can also be avoided by using multimedia presentations (combining images with speech) or animations, which have been shown to be more effective than static images

Reducing cognitive overload by breaking down learning
Third Space Learning Year 6 place value lesson

Third Space Learning lessons are broken down into 4 stages, encouraging students to move from guided practice to independent practice. In the ‘Follow me’ stage, pupils follow their tutor’s worked example before attempting their own. Students can use their tutor’s worked example to help them, before moving on to answer questions more independently.

3. Redundancy effect

When students process information that is not directly related to the learning process, it takes away cognitive resources that could be given to the germane load of the task. 

Redundant information includes:

  • Wall displays at the front of the classroom.
  • Images on PowerPoint presentations for decoration.
  • Clutter on desks.
  • Work left on a whiteboard from the previous lesson.
  • Teacher movement around the room when students are copying from the board.
  • ‘Hiding’ a maths question within a long-worded question for novice learners.

How to avoid the redundancy effect

Removing wall displays from the front of the room, removing clutter from students’ learning environment and having a clean whiteboard at the start of every lesson can help reduce the redundancy effect. 

When students are learning a new topic, it is best to ask direct questions that require little interpretation of the question, while expert learners will benefit more from questions that require deciphering.


A ship sails from A to B on a bearing of 150⁰ for 7km. It then sails a further 10km from B to C on a bearing of 265⁰. Find the distance of A from C.


Working out to reduce cognitive overload

Third Space Learning’s online one to one maths intervention lessons are designed to guide students from guided practice to independent practice. Our sessions ensure students confidently apply maths skills in simpler contexts before adding challenges through more complex, exam-style problem solving questions.

Cognitive overload reduced in a Third Space Learning GCSE lesson
Example question from Third Space Learning’s online one to one maths intervention
Cognitive overload reduced in a GCSE lesson by Third Space Learning
Example challenge question from Third Space Learning’s online one to one maths intervention

4. Information overload

Presenting novice learners with too much information in a single lesson or during a series of lessons can cause a student’s working memory to be overloaded. Trying to assimilate too much information into existing schemas or retrieving prior knowledge from multiple schemas increases the cognitive load on the central executive and episodic buffer. 

How to avoid information overload

Limit the amount of information presented in a single lesson or chunking new material into meaningful groups to reduce cognitive load. Let pupils use notes or a calculator to reduce the amount of information that needs to be recalled from students’ long term memory and allow them to focus all of their attention on the new skill. 

For example, when learning a new skill or method, our sessions remove potential barriers to learning to scaffold and support their initial stages, through notes, images and diagrams. As pupils become more confident and able, slowly remove scaffolding to encourage pupils to engage in independent practice.

Cognitive overload reduced in a Third Space Learning SATs lesson
Example slide from Third Space Learning’s online one to one maths intervention

5. Cognitive overload from problem-solving and discovery learning

Problem solving and discovery learning have intentionally high extraneous load. This causes a problem for novice learners, as the activities also have a high intrinsic load, which takes cognitive resources away from the germane load of the task. 

Novice learners benefit more from clear examples and direct instruction than they do from problem-solving and discovery learning. However, the expertise reversal effect explains that expert learners will get a greater benefit out of the latter approaches. 

How to avoid cognitive overload from problem-solving and discovery learning

Problem-solving and discovery learning should only be used when their learners have become experts and not as a means of introducing a new topic to novice learners. As teachers, we must understand where pupils are in their learning journey and what they will benefit most from at their stage.

Reducing cognitive overload
A challenge slide from Third Space Learning’s GCSE Revision online intervention program

At Third Space Learning, we offer truly personalised programmes. All sessions break down topics into manageable steps so that tutors can work through lessons at a pace which best suits each pupil. Only when pupils are ready do we begin to remove scaffolding.

It also means that we build challenge into all of our programmes, from KS2 up to GCSE, for pupils who show a strong understanding of a topic and who will benefit from more challenging problem solving questions and discovery learning. 

How does cognitive overload affect learners?

When cognitive overload occurs, students do not have the cognitive resources available for learning to occur effectively. 

Cognitive overload can:

  • Impair availability of cognitive resources for effective learning.
  • Induce stress or anxiety during periods of cognitive overload.
  • Leads to feelings of being overwhelmed, difficulty focusing, and confusion.
  • Increase demands on working memory due to stress and anxiety.
  • Reduce students’ ability to learn significantly, especially in the case of maths anxiety.
  • Require investment in creating opportunities for success and a safe learning environment to alleviate anxiety.
  • Cause cognitive overload when students face tasks beyond their current expertise level.
  • Decrease students’ motivation and overall well-being over time.
  • Demand differentiation in the classroom to minimise intrinsic load for students with different abilities.
  • Require instructional design to reduce the extraneous load of tasks.
Read more: Growth mindset

How teachers can prevent cognitive overload

Cognitive overload occurs when an element of the working memory or type of cognitive load reaches its capacity. When this happens, learning becomes much harder. 

Teachers can prevent cognitive overload in the following ways:

  • Minimise the intrinsic load by matching the difficulty of a task to the expertise of the learner.
  • Present information that can be processed by different components of students’ working memory.
  • Limit the presence of external stimuli that do not directly contribute to the learning outcomes of the lesson, such as background noise or music.
  • Avoid the need for pupils to multitask when learning a new skill by providing prompts, definitions of keywords, or use of a calculator.
  • Narrate over images or animations.
  • Introduce one new skill at a time to novice learners.
  • Avoid problem-solving questions and discovery learning opportunities for novice learners.

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Cognitive overload FAQs

What is cognitive overload?

Cognitive overload occurs when the cognitive demands being placed on a student’s working memory negatively impact learning.

How does cognitive overload affect learners?

In addition to impairing the learning process, cognitive overload can be a source of stress and anxiety, cause demotivation, and decrease students’ well-being.

How can cognitive overload be prevented in lessons?

Reducing the intrinsic and extraneous cognitive loads of classroom activities can prevent cognitive overload. The task difficulty should be matched to students’ expertise to reduce intrinsic load. Explicit instruction, removing redundant information, and using multiple components of students’ working memory will reduce the extraneous load.

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