2.2: Understanding the evidence

Time allocation

50 minutes


  • Read the information and look at the examples provided.
  • As you do this, make notes in response to the key questions below.
  • You will need to take the notes with you to your first mentor session for discussion with your mentor.

The intended outcomes of this activity are for you to:

Learn that
2.1 Learning involves a lasting change in pupils’ capabilities or understanding.
2.3 An important factor in learning is memory, which can be thought of as comprising two elements: working memory and long-term memory.
2.4 Working memory is where information that is being actively processed is held, but its capacity is limited and can be overloaded.
2.5 Long-term memory can be considered as a store of knowledge that changes as pupils learn by integrating new ideas with existing knowledge.
3.7 In all subject areas, pupils learn new ideas by linking those ideas to existing knowledge, organising this knowledge into increasingly complex mental models (or “schemata”); carefully sequencing teaching to facilitate this process is important.

In your notepad – key questions

Keep a note of your responses to the following questions and bring them with you to your first mentor session for this Block to inform your discussions.

  • What do you understand as the difference between long-term memory and working memory?
  • What happens when the working memory becomes overloaded?
  • How might this affect learning in the classroom?
  • What are some of the techniques which you read about which a teacher can use to ensure that pupils don’t become overloaded?

Learning involves a lasting change in pupils’ capabilities or understanding

“Much of teaching is about helping students master new knowledge and skills and then helping students not to forget what they have learned.” (Pachler et al., 2007)

One of the perennial frustrations of teaching is when you think that you have taught something really well and pupils have learnt it as demonstrated in their classwork, homework and class discussions, only to find that they have entirely forgotten it within a few weeks, months or in the worst cases, days.

However frustrating, the fact is that if your pupils do not remember the new knowledge or skill then it is for one reason: it has not embedded in their long-term memory. For students to learn, they must transfer information from their working memory into their long-term memory (Deans of Impact, 2015). Learning is a lasting change in understanding and capability. Understanding how learning takes place, and barriers to it occurring, is vitally important for teachers.

An important factor in learning is memory, which can be thought of as comprising two elements: working memory and long-term memory

In your notepad

Look at the definitions below for long-term memory and working memory.

  • Are you clear on the difference between long-term and working memory?
Long-term memoryWorking memory
A vast storehouse in which you maintain your factual knowledge about the world… long-term memory resides outside of awareness. It lies quietly until it is needed, and then enters the working memory and so becomes conscious. (Willingham, 2009)Part of the short-term memory, the working memory is a short-term store for information required during thought processes. (Braddeley, 2003)
The diagram provides a simple illustration of the mind, indicating that experiences of the external
Environment enter the Working Memory (the site of awareness and thinking) before being stored in
the Long-term Memory (as factual knowledge and procedural knowledge). Arrows indicate that
information can also be recalled from the Long-term Memory to be used in the Working Memory
when needed.

Both long-term and working memory play important roles in learning.

When we encounter something new which has the potential to be learnt – for example learning about lines of symmetry in maths – it is first processed in the working memory before transitioning into the long-term memory once it has been learnt.

New information that we notice in our environment (e.g. what the teacher is teaching) interacts in our working memory with prior knowledge, which is stored in the long-term memory. In this case, knowledge the pupil has stored in their long-term memory related to symmetry, perhaps from work in Drama on reflections and mirroring, can be pulled into the working memory to support understanding of the new knowledge.

When the pupil learns the definition of symmetry and how to recognise lines of symmetry in shapes this new knowledge will either be forgotten or begin its journey to move into their long-term memory where it can be called upon when needed – in other words it has been learnt.

Long-term memory can be considered as a store of knowledge that changes as pupils learn by integrating new ideas with existing knowledge

Our long-term memory sorts and stores all information into categories, or schemata (Kirschner et al., 2018). These “interconnected webs of information” group information so you don’t need to remember lots of individual pieces of knowledge.

When the pupil learns about lines of symmetry in maths, their schema on “shape properties” is added to and adapts to absorb the new information. If learnt, symmetry is now stored in their long-term memory. Next time they encounter it, they will be able to pull the learning into their working memory to interact with other new stimuli in the environment and overtime engage in more complex applications of the concept, for example recognising symmetry in compositions in art.

Of course, not all information that makes its way into our long-term memory will be there forever. The reason you may forget something which you previously knew (such as your childhood best friend’s phone number) relates to two things:

  • retrieval strength, or how often you access the memory over time; and
  • storage strength, or how deeply embedded the information was in your long-term memory including how many schemata the individual item is linked to.


In the example below, the teacher applies their understanding of long-term memory, schema and working memory when introducing new content.

  • How does the teacher help pupils to retrieve information from their long-term memory?
  • What techniques do they use to make the information available in the working memory for the next task?

Teacher: “We’ve been reading some really spooky stories and today we are going to start thinking about some vocabulary we can use when we draft our own scary stories. Can anyone remember some of the words we found yesterday in our story book?”

Pupils: Scary, Spooky, Mysterious, Monster, Eerie, Twisted

Teacher: “Yes, they’re perfect – they make me shiver! The monster in that story was REALLY scary!

What other scary stories have you read?”

Pupils offer Goosebumps as a popular choice.

Teacher: “How would you think of scary words? What could you do?”

Pupils offer: think about books they have read at home, movies they have watched at home or pictures they have seen.

Teacher: “Now, have a look around the room and you can see lots of different images which might inspire you. Each table has a big piece of paper. I’m going to give you 5 minutes to work in your groups to think about all of the scary stories you have heard or read before and to list out as many different words which you associate with scary stories as possible. An example to get you started – I know that ghosts are scary so I am going to write that down.”

[Pupils complete the task]

Teacher: “Wow, we have so many amazing words for everyone here! I am now going to put these up on the wall so you can look up and use both the pictures and now our word banks to inspire your writing! Let’s read and talk about them as we put them up”.

Working memory is where information that is being actively processed is held, but its capacity is limited and can be overloaded

The implications of how memory works for classroom teaching are significant.

In particular, the capacity limitations of the working memory affect how pupils learn.

As you have just seen, working memory is the processing area of the memory. Unlike the long-term memory (which has infinite capacity to store information), the working memory can only handle a limited amount at one time (thought to be between 5 and 9 items). If a pupil experiences cognitive overload, whereby the amount of information they need to hold exceeds the processing capacity of the working memory, they will be unable to complete the task or engage with it meaningfully.

What you might see in your classroom for a pupil who is experiencing cognitive overload:

  • Incomplete recall of instructions
  • Missing out or repeating parts of a task
  • Giving up as the task seems overwhelmingly complex
  • Appears to be inattentive, have a short attention span, and be easily distracted.

(Adapted from Gathercole, et al., 2006)

Sweller (2016) tells us that since working memory has a limited capacity, instructional methods need to avoid overloading it with additional activities and information which don’t directly contribute to the learning. This might include unnecessarily detailed examples or going off on a tangent rather than clearly focusing on the content which pupils need to learn.

There are several techniques which are useful in the classroom for reducing the cognitive load on the working memory.

1. Take into account pupils’ prior knowledge when planning how much new information to introduce and link what pupils already know to what is being taught

Helping pupils to draw on prior knowledge – linking to existing schemata – when they encounter new knowledge will reduce the burden on the working memory. For teachers this has two implications. Firstly, you should think carefully about what pupils already know about the area of learning. If their knowledge is limited, you should be especially careful when introducing new material and be very conscious of the risk of overloading pupils with too much information. Secondly, you should link the new learning to what you believe they already know. We will look in more detail at the role of prior knowledge in Activity 2.3.


The final version of this video will be available from spring 2021, as the publication of this programme was fast-tracked in response to disruptions to this year’s initial teacher training.

Video type

Classroom practice

Short description

An Early Years classroom, the video shows how a teacher takes prior knowledge into account when introducing content and directly links what pupils already know to what is being taught.

What should you focus on in this video?

  • What do you notice about how the teacher links the new material to pupils’ prior knowledge to help them learn the new word?
  • How does the teacher take into account prior knowledge before introducing the new word?

Video script

Pupils have been listening to and participating in a variety of songs and stories on a space travel theme, the initial interest for which was originally observed during free play.

The role play area has subsequently been developed to include a rocket and related resources. The teacher has noted that the children have begun to use previously introduced space travel story vocabulary in their play and are beginning to talk about where they will go on their adventures. The teacher is keen to introduce a new word: future.

This week the children have been reading the story ‘Astro Girl’.

Teacher: This week we’ve been reading ‘Astro Girl’, another space story! Let’s read it again!

Teacher reads the story in an engaging way, using movement, gesture and varied tone to ensure continued interest. The focus is on the flow of the story and any complex or unfamiliar vocabulary has been previously discussed.

Teacher: So, Astrid wants to be an astronaut in the future. That’s a new word, ‘future’. Does anyone know what it means?

Child 1: I know how to get into the future! We need to go in an electric, really fast transformer car. When we get there, we find treasure. Treasure with food in it!

Teacher: Wow, that sounds really exciting! I know you like cars that go really fast! In this story, Astrid wants to be an astronaut in the future. Future means something that hasn’t happened yet…like when Astrid has grown up.

Child 2: I’m going to be a dancer when I have growed up.

Teacher: I remember your dancing show! The future just means something that hasn’t happened yet but is going to. It can even mean tomorrow. I’m taking my cat to see the vet tomorrow.

Child 3: I’m going to my grandma’s tomorrow.

Teacher: Are you? We’ll that’s in the future! It hasn’t happened yet. Sometimes the future is something very soon but sometimes it’s a long way ahead.

[During free play, the teacher supports the conversation to include the new word and where the children will travel next on their adventures.]

At the end of the day, the practitioner talks to the children about their plans for the weekend again, reminding them that it’s in the future because it hasn’t happened yet. It’s important that the examples given are within the children’s realm of experience and that they hear this word several times to get a clear understanding of it.

2. Avoid overloading the working memory by considering how much new material to introduce at one time and breaking complex material into smaller steps

Another practical way you can avoid overloading working memory is to only introduce new material in small, manageable steps (Rosenshine, 2012). Ensuring pupils master foundational material and that it has had time to embed in the long-term memory before moving on will prevent working memory from becoming overloaded and support pupils to engage with more complex material. This is also true when teaching complex material to pupils: breaking it down and supporting pupils’ working memory with partially completed examples can help avoid cognitive overload.


In the examples below, both teachers want their pupils to learn some complex material about the effects of war on a country. Think about these questions:

  • Which teacher will be more successful?
  • Why?
  • How does Teacher B take cognitive load into account when teaching the material?

Example A

  • Teacher A teaches the content from the front. They speak for 35 minutes to cover all of the key factors related to the effects of war.
  • The teacher has planned to begin with an overview of the overall impact under specific headings (Social, Economic, Political) and then work backwards to explain the contributing factors (Debt, Displacement, Lack of Education etc).
  • After 35 minutes they pause for questions from the pupils of which there are a few, but mostly about the last point the teacher made.
  • The teacher sets the pupils a writing task to describe the main effects of war for the remaining 20 minutes of the lesson.

Example B

  • Teacher B teaches the same content from the front.
  • However, they introduce each factor one at a time.
  • The order of the content has been carefully sequenced to ensure that more complex ideas are only introduced once foundational factors have been covered (for example, building up to the concept of socio-economic impact only after understanding the effects of debt and mass unemployment).
  • After they introduce each factor, they pause, and both take questions and pose questions to the pupils. They respond to these questions with further explanations and examples.
  • They provide the pupils with a workbook to complete. Each factor has a page which has been broken into key categories. For example, there is a section on ‘Definition’, ‘Example’, ‘Three key points’, ‘Important vocabulary’.
  • The teacher has partially completed some of the boxes, for example adding the key vocabulary and pupils need to add the definitions or including the definition and pupils need to add the key vocabulary.
  • The teacher gives pupils a few minutes to complete the page in their workbook after each factor is introduced before continuing.
  • This takes up the entire lesson.

3. Reduce distractions which take attention away from what is being taught so that attention is focused on the content

Because working memory is limited, it is important that you avoid overloading it with unnecessary information that doesn’t directly contribute to pupil learning. It can be easy to mistake engagement and enjoyment for learning. Activities must be centered around what we want pupils to learn. While superficially appealing, it is easy to get carried away planning ‘fun’ activities that actually take pupils’ attention away from the content. For example, in a game to complete as many questions in the time as possible, pupils are likely to be thinking about the time limit and how many questions they complete at the expense of thinking hard about the content.

This is not to say that you should avoid planning activities for pupils. You can make learning both active and focused on the content. Consider a ‘hook’ activity at the start of a topic on DNA. The teacher sets up a crime scene and pupils collect clues to solve a Whodunnit. At this stage pupils do not have enough content knowledge to engage meaningfully with the topic, and so the lesson takes time away from understanding the foundational knowledge of this topic. Instead, the teacher could teach the content they need to learn first and then pupils complete the Whodunnit when they are ready to apply their learning to a new context.

Another factor to consider is complexity. If a pupil cannot easily follow the steps of a task then their working memory will be preoccupied with trying to remember what they are supposed to do rather than thinking about the content. Similarly, if a pupil cannot decipher the main point of your explanation their working memory will be distracted by trying to figure out what is important to remember and what is not.

Some things you can do to reduce distractions include:

  • Focus activities and tasks on the content rather than distracting ‘games’ which have little to do with the material.
  • Ensure that there is a thinking element involved in activities such as ordering, sorting, grouping or matching.
  • Every activity should be focused on the content and what you want pupils to learn. If it is not, do not use the activity.
  • Consider when you use an activity to ensure pupils have the required knowledge to participate fully in it.
  • Minimise the complexity of tasks so pupils don’t need to remember lots of steps.
  • For more complicated tasks, write the steps which pupils need to remember on the board and leave them there so pupils can refer back to them during the task.
  • Use short, clear explanations and examples to demonstrate your points – plan these in advance so they are high quality and concise.


The final version of this video will be available from spring 2021, as the publication of this programme was fast-tracked in response to disruptions to this year’s initial teacher training.

Video type

Classroom practice

Short description

A GCSE Biology lesson. A science teacher trying to teach their class about DNA and chromosomes.

What should you focus on in this video?

  • How clear is the teacher’s explanation at the start of the lesson?
  • How does the activity either contribute to or distract attention away from what is trying to be taught?
  • What would this feel like as a pupil?
  • Why do you think the pupils couldn’t answer the question at the end?

Video script

Teacher: Today we are learning about DNA. DNA controls the colour of our eyes and our skin and other things. We are going to do an activity which demonstrates how the chromosomes work in pairs to pass on information to a new cell. Chromosomes make up our DNA. If the pairs are messed up, that is when we get things like diseases, but they also decide whether we are male or female when we are born because of the X and Y. If you have the same, you’re a girl and different you’re a boy. You’ve got 23 socks in your pile, and I want you to try and match them up as fast as you can to the socks on the washing lines like our chromosomes pair up! Everyone ready? OK, go!

Pupils dash to match up the socks.

Teacher: OK, if I want you to now give me the chromosomes for a girl baby, what would you do?

Pupils show confusion and no answer offered.

Teacher: Right, let’s go back to the start…


The final version of this video will be available from spring 2021, as the publication of this programme was fast-tracked in response to disruptions to this year’s initial teacher training.

Video type

Classroom practice

Short description

A GCSE Biology lesson. The same content being taught by a different teacher.

What should you focus on in this video?

  • What is different about how this teacher introduces the same content?
  • How does the teacher make use of prior knowledge in this lesson?
  • How has the teacher reduced distractions in the classroom so that attention is focused on the content?
  • How does this affect the pupils’ cognitive load?
  • What do you notice about the levels of understanding in this classroom compared to the first one?

Video script

Teacher: Today we are learning about DNA. Does anyone know what DNA means?

Pupil: It’s about our genetics so things like our eye colour.

Pupil: I think it’s in our blood.

Teacher: You’re both right. DNA are the molecules which carry our genetic code. This genetic code determines things like your eye colour. Doctors might draw your blood to read your DNA code because it is carried in your blood cells. What other genetic features do you think we get from our DNA? Have a quick chat with your partner to come up with some examples.

Pupils: Skin colour, height, whether you have freckles or not…

Teacher: Great. Let’s look a little closer at what is inside your DNA. Look at this diagram on the board which shows a zoom in of your DNA strand. These thread-like structures are called chromosomes. Each human has 46 chromosomes which are organised into pairs. How many pairs of chromosomes must we each have?

Pupil: 23 pairs of chromosomes.

Teacher: Correct, 23 x 2 = 46 so we have 23 pairs of chromosomes. We receive 23 from our mum and 23 from our dad and they join together to form pairs. One of these pairs will determine whether you are born a boy or a girl. A boy chromosome is called Y, and a X chromosome is female. The chromosome your mum will pass to you is always X (female), but a sperm can carry either an X or a Y so depending on which combination is successful, you’ll be a girl or a boy. Both XXs will be female but an XY will be male. Question?

Pupil: Is it possible to ever have a YY combination?

Teacher: Interesting you should ask… there is a very rare condition…


You can reduce cognitive overload in the classroom using some of these techniques:

  • Linking new learning to existing prior knowledge in the long-term memory to free up working memory space
  • Minimising the complexity of tasks so that pupils can focus on the content rather than being distracted
  • Breaking new and complex content into small, manageable amounts to introduce to pupils
  • Taking your time with new material ‒ don’t rush, give pupils time to process
  • Use memory aids like writing on the whiteboard so pupils don’t need to use working memory when attempting tasks.


Baddeley, A. (2003) Working memory: looking back and looking forward. Nature reviews neuroscience, 4(10), 829‒839.

Deans for Impact (2015) The Science of Learning [Online] Accessible from: [Retrieved 15 May 2020.]

Gathercole, S., Lamont, E., & Alloway, T. (2006) Working memory in the classroom. Working memory and education, 219‒240.

Kirschner, P., Sweller, J., Kirschner, F. & Zambrano, J. (2018) From cognitive load theory to collaborative cognitive load theory. International Journal of Computer-Supported Collaborative Learning, 13(2), 213‒233.

Kirschner, P. & Hendrick, C. (2020) How learning happens: Seminal works in educational psychology and what they mean in practice. Abingdon, Oxon: Routledge.

Pachler, H., Bain, P. M., Bottge, B. A., Graesser, A., Koedinger, K., McDaniel, M., & Metcalfe, J. (2007) Organizing Instruction and Study to Improve Student Learning. US Department of Education.

Rosenshine, B. (2012) Principles of Instruction: Research-based strategies that all teachers should know. American Educator, 12–20. [Online} Accessible from

Shibli, D & West, R. (2018) Cognitive Load Theory and its application in the classroom [Online] Accessible from [Retrieved 15 May 2020.]

Sweller, J., van Merrienboer, J. J. G., & Paas, F. G. W. C. (1998) Cognitive Architecture and Instructional Design. Educational Psychology Review, 10(3), 251–296.

Sweller, J. (2016) Working Memory, Long-term Memory, and Instructional Design. Journal of Applied Research in Memory and Cognition, 5(4), 360–367. [Online] Accessible from

Willingham, D. T. (2009) Why don’t students like school? San Francisco, CA: JosseyBass.

Wittwer, J., & Renkl, A. (2010) How Effective are Instructional Explanations in Example-Based Learning? A Meta-Analytic Review. Educational Psychology Review, 22(4), 393–409.[Online] Accessible from