Do you remember what you learnt in your first lesson of the day today?  Can you remember what you learnt in the first lesson of the day 2 or 3 days ago?  Do you remember what you learnt in your lessons on Monday 23^rd September 2019?  You probably answered Yes, No, No to these three questions and there is a scientific reason why. 

In this blog I will explain why we forget things; how long-term memories are made and how you can use this to your advantage when revising.

Forgetting and Memory

Hermann Ebbinghaus, a German psychologist, conducted studies in the late 1800s based on human memory.  From his research he created the now famous ‘forgetting curve’.

His forgetting curve shows the rate at which most humans forget new knowledge if they never revisit that knowledge, and it is shocking just how quickly we forget!

This means you will probably forget approximately 67% of what you learn this morning by the end of the day, and 6 days later you will have probably forgotten 75%.

 This is not ideal if you are learning lots of new information for many subjects for your GCSEs and A-levels, but there is a way to overcome this!

The Human Brain and Memories

The human brain has an incredible storage strength, meaning it has the capacity to store a lot of information.  Unfortunately, the human brain also has a very poor retrieval strength, meaning the brain struggles to access all this stored information. 

 Each neurone is connected to another neurone via a synapse, which is the name for the small gap between these cells.  This network of neurons and synapses is called a neural pathway, and for you to be able to remember the stored information in your brain this pathway must remain intact. 

When you have forgotten something, the information is still in your brain, but because the neural pathway is no longer intact you cannot retrieve the information anymore.

Where are Memories Made?

The hippocampus is a part of the brain where memories are stored.  This part of the brain is sometimes called the seahorse, because it looks very similar in shape!  

People who have brain damage to their hippocampus are unable to make new memories, as no new neural pathways are made in this region. 

Henry Molaison, born in 1926 and died in 2008, suffered from severe epilepsy in his youth.  He had brain surgery at age 27 to prevent severe fitting, and to do this the surgeons removed both parts of his hippocampus.  His epilepsy was cured, but sadly as the science of memory was not known at this stage and because his hippocampus was removed he never made a new memory again. He spent the remaining 55 years of his life living in the present moment only. 

It is from case studies like these that it has been possible to identify that making neural pathways in the hippocampus of the brain is how memories are made.

Sacrificing Memories

One of my favourite Disney Pixar films is Inside Out (you haven’t seen then I highly recommend it!)  In the film memories are represented as memory balls.   When the main character sleeps each night there are janitor like ‘forgetters’ in her brain who go along the memory ball library and throw out any ‘memory ball’ which hasn’t been used in a long time so that the ball can be recycled to make a new memory.  

This models what is happening in your brain when you sleep, but instead of ‘forgetters’ and ‘memory balls’ we have glial cells and neural pathways (more on glial cells in my upcoming on blog on sleep). 

The purpose of this is to maximise and prioritise the use of your available neurones in the hippocampus.  Each night when you sleep memories are either kept and strengthen or lost.  While you sleep some neural pathways get severed, which results in information you can no longer retrieve, or in another words it is information you have now forgotten. 

Why is Sacrificing Memories Important?

This is important, as you need to maximise the use of your available neurones to enable new memories to be made and to strengthen important memories.  Unimportant memories are lost to enable this to happen.  For example, it is not important for you to remember what you wore and ate for dinner 4 weeks ago so that neural pathway will be severed.  The way the brain ‘decides’ which memories are less important is based on how many times that particular neural pathways is being used.   

If you haven’t used a neural pathway in a long time (meaning you have not thought about or tried to remember that piece of information) then your brain will deem that it is no longer needed and sever this pathway to enable a new memory to be made. 

 This means if you are not frequently recapping your knowledge from your GCSEs or A-levels then the memories of the content could be severed. When you come to revise you will have to re-learn it all over again.

The Solution to Improving Your Long-Term Memory

The key to making memories is spaced retrieval of information.  Try weekly or monthly reviews of content to make sure that the neural pathway gets strengthened in your sleep instead of severed.

Some amount of forgetting though is really important in learning and memory.  Recalling the information after longer gaps requires more thought and energy and therefore it helps to strengthen the long-term memories

Ebbinghaus’ forgetting curve looks very different if you add in spaced retrieval of memories.  The green lines represent how much you can remember if you were to review information each day.

It has been found that they key number of revisits 5 times.  If you space out retrieval and look over the content 5 times before an exam it should strengthen the neural pathway to the point it becomes a long-term memory.

Neural Pathways

The images below show neural pathways in the brain between synapses.  The images show the development of these neural pathways as your learn and strengthen memories.

The more times you retrieve a memory, the stronger the neural pathway in the brain becomes and therefore the better you remember this information. The neural pathway images above show the number or neural pathways that develop after you have first been taught something (far left). 

Picture two and three show the increase in neural pathways when this new information is explained further to you. 

The final image shows increased connectivity and a highly strengthened neural pathway. This only happens with repeated retrieval of the information. Strengthened and highly connected neural pathways like this represent a long-term memory.

One strategy I am using to encourage this is on my @MissEtruch Instagram.  Every day I post several multiple-choice quiz questions to help maintain and strength the neural pathways for each biology topic. 

Great Idea, But I’m Not Going to Do It

The concept of spaced retrieval, or revising multiple times, probably isn’t news to you. Teachers are always telling students to revise and consistently consolidate their work, so why do lots of you still not do it?

The answer is because it is hard to stick to. Although we know this strategy is more effective in creating long term memories, it is not intuitive for us to follow.  This strategy takes a lot of effort, continual hard work, and commitment however you don’t see the payoff and benefits until much later. 

Long-term Payoff

Without any instant ‘rewards’ it makes spaced retrieval very difficult to stick to.  This is why many students fall back into the pattern of cramming. It takes less time, less effort and you see the impact of this work instantly.  However, this strategy does not create long term memories and strengthen neural pathways. Therefore, for linear exams (like the GCSE and A-level) this strategy will not work. This brings me back again to my favourite quote.

Dark times lie ahead of us and there will be a time when we must choose between what is easy and what is right.

ALBUS DUMBLEDORE – J.K ROWLING

For strategies that will work and will help with this spaced retrieval make sure you subscribe so you don’t miss the next article.

Next time I will discuss and model active revision strategies that you could use to revise for your GCSE and A-level examinations.

You may also like:

@missestruchbiology Instagram

YouTube https://www.youtube.com/channel/UCN4caNO-iJ8-4jGB1WOdo9w

BIBLIOGRAPHY

Evans, J. & Hewitt, J., 2020. Make their learning Memorable. Teach Secondary, Issue 9.1, pp. 60-61.

Furst, E., 2018. From Neuroscience to the Classroom. Research ED, Issue 2, pp. 32-35.

Learnus, 2020. Should we know a little more about what is under the bonnet: Stuff about the Brain. London: LearnusUk.