A very brief introduction to memory

by Saskia Neumann

Photo by Anita Ishaq

Without memory, there is no culture. Without memory, there would be no civilization, no society, no future.

Elie Wiesel

Memory plays a very important role in defining who we are and who others are indeed. Without our memories, it would be hard to say who we are. Am I a person who is used to always waking up at the same time and to going to the same library everyday? Or do I tend to be more adventurous and invent every new day anew for myself? Who is this person waking up next to me every day? Hopefully, my partner. But we would not be able to answer all these questions if it was not for our memory. What exactly is this little device which helps us to remember who we and others are? 

Memory

Did you ever type in some digits into your phone just to forget them a few seconds later? Do you remember your brother’s birthday, and did you remember to actually give him a call on his birthday? These are all instances of memory. Remembering how to dance, remembering that you were born on the 4th July, remembering what happened at most of your birthday parties and remembering that you have never been to America on the 4th July are also all very different instances of one and the same thing: your memory. These examples help us to realize that memory is not uniform but comes in many different forms. Yet, which are these different forms and how do they differ from each other? 

Short-term memory and waking memory

Nowadays, we have QR codes to add each other on WhatsApp, Telegram, Line and all of the other messenger services we use. However, when I was younger and I wanted to have someone’s phone number, they had to read it out loud and I had to repeat it back to them so that I could write the digits down in my address book. This is made possible by our so-called short-term memory. Our short-term memory holds a limited amount of information in an active state to enable us to work with this information. In the case of the phone number, our short-term memory is responsible for enabling us to repeat back the series of numbers we just heard and to consequently write them down. 

Our short-term memory is part of a bigger memory system which is called working memory. If you are a student like me and you go grocery shopping, you probably add up in your head the different prices for the groceries you put in your cart. An apple may be 0.50$ and bread 1.20$ and some cookies 1.50$. Keeping these prices in your head is achieved with the use of your short-term memory. If you want to work with the information you have, though, you need your working memory. Our working memory enables us to add up the individual prices and to know what we will have to pay in the end.  

Long-term memory and prospective memory

Imagine that you meet your best friend Sarah right when you read some advertisement on your way to your weekly running training, and she very excitedly tells you about the date of the upcoming concert of your favorite band. While you probably would not need to remember a phone number you have already written down or the advertisement you just read after a few minutes, the date of the concert is important enough to not only store for a short period of time but at least up until the time you want to visit the concert. Storing information for a longer period and being able to recall information even after we have not thought about the information for a while is achieved by our long-term memory.  

Now that you know when the concert will take place, you also need to go there. Or else, you will miss out on all the fun you could have there. For this, you don’t only need to know when the concert takes place, you also need to remember to actually go to the concert on that day. The part of memory which is responsible for fulfilling your intention to go to the concert is called prospective memory.

Implicit and explicit memory

Long term memory is responsible for storing the type of memories I mentioned at the beginning of this article, like the memories of your birthday parties and the date of your birth. But also, of how to dance. Even though we did not constantly think about these things, we are able to access these memories once we want to with the help of our long-term memory. Yet, our long-term memory also does not come in one unitary form. It is divided into the so-called explicit and implicit memory. 

When we dance, we remember how to dance but we are not able to tell how we are able to dance once we are asked. We can’t access our knowledge of how to dance consciously, but we have something which we usually call muscle memory. A similar phenomenon can be found in Pavlov’s dog, the very one who was trained to salivate (in anticipation of food) when a bell rang. Pavlov’s dog and us remembering how to dance are instances of implicit memory. Implicit memory is unintentional and unconscious remembering. 

Explicit memory, in contrast, is the form of memory we can access consciously, such as the date of our birthday. When we are asked about the date of our birthday, we are able to access this information and share it with another person. Explicit memory is divided into two parts: semantic memory and episodic memory. The former is our memory of concepts and facts like remembering that our birthday is on a specific date. To remember semantically, we don’t need to have personally experienced the events we recall. Semantic memory stands in contrast to episodic memory. Episodic memory is our memory of episodes of our lives, and we thus need to have experienced the events of our past ourselves to remember them episodically. For instance, we need to have been at our birthday parties to remember our birthday parties. 

Memory conquered?!

We have now learnt how to divide (and maybe conquer?) our memory into different sub-parts. Short-term memory is part of working-memory and differs from long-term memory in its capacity to store information timewise. Long-term memory is divided into implicit and explicit memory. Distinguishing the different sub-parts of memory leads to many interesting questions. For instance, what exactly is remembering and what is forgetting? Do people still remember if parts of their memory do not work anymore such as in people with amnesia? Are only parts of our memory responsible for our knowledge about ourselves and the world? Memory raises many questions. It’s time to answer them!