As you read this sentence, your working memory stores information temporarily to allow you to understand it until the end. Meanwhile your short term memory is already encoding its information for later use and for you to relate it to the rest of the paragraph. Your long term memory might even store it for you to remember it several years from now. How memory works exactly is still studied today, but the Multi Store Model gives a good overview of how our brain organizes and stores information.
introduction
If we show you a random shape, your eyes will send the information to your brain which will then decide what to do with it – perhaps not much. If we show you another shape, your senses will again send it to your brain, but now it might be able to find some related information that was stored in your memory. What’s going on here?
how’s memory work?
You may have forgotten, but when you were young, you knew nothing. The first time you saw a particular shape, it was meaningless. Over time and in search for order, you started to recognize patterns. One day someone gave that particular thing meaning, your mind labeled it as important and decided to store it for future use.
The next time you see that thing, you recognize it and link it to a previous experience. The more often you make such meaningful experiences, the more data will be stored in your memory and your understanding of that matter grows. And one day, when you see that particular shape you’ll say “it’s an ape!”, and if you give your mind some time to look up all those memories, it might come up with lots of things you can relate to this one piece of digital ink. So how does your memory work?
multi-store model
The multi-store model asserts that the human brain has three processors.
- A sensory register, where new information enters.
- a short term memory, which quickly assesses the input, and
- a long-term store, where it can potentially be held forever.
We need attention to get things to the short-term memory, rehearsal to hold it there for longer and transfer for sending it to long term storage — and bringing it back. Let’s now try to understand how everything interacts.
Sensory register
Our life is a continuous stream of stimuli that we perceive in different ways. There are our senses such as vision, touch, smell, hearing and taste. There are internal states such as stress, sleepiness, or hunger. And there are emotions, wants and intentions. All of them are part of the sensory input that our brain has to process all the time.
The sensory register can perceive any such new stimuli. They are then filtered by attention processes and decomposed into manageable chunks. These chunks of information are then sent further.
short-term memory
The short-term memory holds the new info for a moment. Then it will either forget it, transfer it to the long term memory, or instantly use it by bringing it to our attention.
Also known as working memory, our attention can hold about 7 bits of information for a few seconds to complete a task. If we pay attention, our brain can send fresh memories to the long-term store. This happens especially well when we rest. During sleep we tend to consolidate important things and discard others — which we then forget.
long-term memory
The Long-term memory is a vast library of stories, experiences, facts and concepts, some of which we can recall for life, and others we are unable to remember the next day. Inside this long-term store are again different types of memories.
There are episodic memories which are chunks of detailed information with a high emotional value. Such as all your stories, some of which you might be able to recall in great detail. Like the first day of school or your first kiss. Maybe you can even recall some specific thoughts from that day.
There are semantic memories, things like facts or general knowledge. Repeated episodic memories, like the way to school, can also, over time, turn into semantic information. You can think of such memories as a large network of ideas: If you see a particular shape, you may think: gorilla – ape – human – intelligence.
Episodic and semantic memories are known as explicit memories. They are conscious recollections. They are all the information and experiences we know we hold.
There are also implicit memories, skills and things you are not aware of. The process of walking relies on muscle memory. You’ve learned it by trying and failing, and today you have no idea how you actually do it. Implicit memories are also at work when we unconsciously react to a stimulus — a process known as conditioning.
creating your own memory
To make things more complicated, our memories often change. Sometimes we forget parts, sometimes we add new details to old memories in response to how we feel right now. When we think of a holiday we took with someone we don’t like anymore, a trip that was actually nice, might be remembered as unpleasant today.
So next time you see this or that shape, you might want to pause and pay tribute to the fact that there are more connections in your brain than stars in the universe, here to help you organize inputs, thoughts and memories to get you through life.
Now, the best thing about memories is still creating them! Trying new things, failing and then trying them again is one good way to do just that!
Sources
- Multi store model – Wikipedia.org
- Martinelli, P., Sperduti, M., & Piolino, P. (2013). Neural substrates of the self-memory system: new insights from a meta-analysis. Human brain mapping, 34(7), 1515–1529.
- Moscovitch, M., Rosenbaum, R. S., Gilboa, A., Addis, D. R., Westmacott, R., Grady, C., McAndrews, M. P., Levine, B., Black, S., Winocur, G., & Nadel, L. (2005). Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory. Journal of anatomy, 207(1), 35–66.
- Moscovitch, M., Cabeza, R., Winocur, G., & Nadel, L. (2016). Episodic Memory and Beyond: The Hippocampus and Neocortex in Transformation. Annual review of psychology, 67, 105–134.
- D’Esposito, M., & Postle, B. R. (2015). The cognitive neuroscience of working memory. Annual review of psychology, 66, 115–142.
Dig deeper!
- Read a simple explanation of the multi store model of memory
- Read an improvement on the multi store model: Tulving’s model of memory
- Read about another theory on memory: the multi-trace theory and how memory is organized in key areas of the brain
- Read a study done on the Taxi drivers of London, showing how memory is formed in the brain and a follow up review
- To dig even deeper, read about the cellular mechanisms behind memory
Classroom Activity
- In this activity students are going to learn about different types of memory.
- Plato said that existence is only the accumulation of experience, and that humans are only the result of their memories. Share this with the class and ask them to discuss this sentence and what they think about it.
- Show them Sprouts’ videos about types of memory.
- Ask the students if they want to change the answer they had given during the debate.
- Share with the class that latest advances in research on memory find that memories play a fundamental part in the creation of the self and of our personalities, and that therefore Plato was close to the truth.
- Discuss with the students if they think that forgetting information and having biases is an imperfection of our memory or an evolutive trait that provides some advantage.
Collaborators
- Script: Nitika Arora, Ludo, Jonas Koblin
- Artist: Pascal Gaggelli
- Voice: Matt Abbott
- Coloring: Nalin
- Editing: Peera Lertsukittipongsa
- Sound Design: Miguel Ojeda
- Production: Selina Bador
