Long-Term Memory

In this video I cover the final box in the 3-box model of memory, long-term memory. Long-term memory is generally considered to have an unlimited capacity and thus is never “full”. I explain different types of long-term memory which can be broadly divided into explicit (or declarative) memory and implicit (or non-declarative) memory. These can then be further divided into semantic memory and episodic memory (both explicit) and procedural memory (implicit). I end by considering the simplifications involved in creating memory models and the importance of reminding ourselves just how complex memory processing really is.


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Video Transcript:
Hi, I’m Michael Corayer and this is Psych Exam Review. In this video we’ll be looking at the last box in our three box model and this is the long-term memory store.

The first thing to note about our long-term memory store is that it seems to have an unlimited capacity. By that I mean it can never really be full. It’s not the case that somebody’s memory can be so full that they can’t store anything new without getting rid of something else. In fact it seems that the more you know then the more easily you can integrate new information because you have more things that you can connect it to and that makes it actually easier to remember new things. So when we look closely at long-term memory, just like with the other boxes in our model, when we look closely at it we see that actually there’s multiple parts to it.

When we talk about long-term memory we can actually be referring to a number of different things. Just like with sensory memory, you know that actually refers to information from all of the senses, just like short-term memory, then begin to include working memory which then has its components. Now if we look closely at long-term memory we can roughly divide it up into two main parts and then we’ll see that each of those have other parts as well.

So the first type of long-term memory that we can look at is called explicit memory. You may also see this called declarative memory. This is memory for things that we can talk about, things that we can declare. We hold information and we can talk about. So the first type of explicit memory that we have is semantic memory. What semantic memory refers to is factual knowledge. So if I ask you “what’s the capital of France?” you can come up with a factual answer that you’ve learned.

Or if I ask you what a particular word means hat would be a type of semantic knowledge. Factual knowledge of the world; names, dates, places, word meanings, these types of things would all be considered semantic memory. But that’s not the only type of memory that you can talk about. We also have the next type of explicit memory and this is our episodic memory.

Episodic memory refers to narratives episodes. So it’s narratives and events. Now a good way to think about this is if I were to ask you “what did you do yesterday?”. The answer that you’re going to give me is probably going to be an episodic memory. You’re going to give me some of the major events and sort of the narrative and what it meant for you. You’re not going to give me a list of facts.

I mean there’s essentially an infinite number of facts you could tell me about what you did yesterday. You can tell me “At 3:04 p.m. and 27 seconds, I stood up and I took 15 steps to the refrigerator and then I applied four and a half pounds of force to the handle in order to open it” technically those are all facts about your day that you could tell me when I ask you what you did yesterday, but that’s really not what I’m asking for. What I’m asking for is the narrative.

I’m asking what happened to you that was interesting yesterday? What had meaning? And you’re really when we create our episodic memory, we’re able to extract the gist of things. We have all of this factual information that we could encode, we could draw upon and yet we somehow automatically condense it down. It’s really amazing that our minds are able to do this.

Things happen to us, we spend an hour at some event and we can just automatically condense that down into, you know, a two or three sentence description about what it all meant when somebody says “hey how was, you know, how was that event you went to?”. You don’t have to sift through all, it’s like automatically been sifted through and you can just spit out “well here’s what it meant, here was what was interesting about it, here’s how it influenced me”. It’s amazing that we can do this and so when a lot of people talk about you know improving their memory or wanting to, wishing they had a better memory or something like that, often the focus is I think too much on this idea of factual knowledge and semantic knowledge.

This idea that you know if I could just remember more facts, you know everything would be easier. When in fact it seems that that’s the least important type of explicit memory that we have. I mean facts are like you know there’s an infinite number of them and so we don’t want to remember all of them. I mean what would be the point right?

It’s actually more amazing that we can sift through and pull out the meaningful ones very easily. Ok, so that’s our episodic memory and the next type of memory that we have in our long-term memory is our implicit memory. Or you may see this referred to as non-declarative memory. Okay so what do we mean by implicit memory? Well the most common type of implicit memory that is usually referred to is what’s called procedural memory. What procedural memory refers to is our knowledge for how to do things and this is implicit or non declarative because we can’t really talk about it.

So if I ask you “how do you ride a bike?”, I mean you know how to ride a bike, let’s say, but when it comes to telling me you don’t really have access to that. You know you can try to describe “well okay you put your feet here, you sit here, you hold the handlebars” but that’s not really telling me how to do it. You just have to do it. It’s an implicit memory and that you can perform it but you don’t necessarily have declarative access to this and it’s hard to explain how you do it.

In the same way I might ask you “how do you tie your shoes?”. Now of course you know how to tie your shoes but you might find when you want to give me the instructions you actually have to do it and like watch what your hands are doing and say “okay I guess I do this and then I pull this through here”. So when you do that behavior it’s not that you’re calling up a list of instructions and following them, right? It’s that you’re doing it and from that you can try to create a list of instructions but it’s not really how you do it.

So that’s the difference between this explicit and implicit memory and there are other types of implicit memory and when we get to the unit on consciousness maybe I’ll talk a little bit about other types of unconscious influences on behavior and how those might be a part of our implicit memory but for now if you know the idea of procedural memory as being an implicit memory that should be sufficient.

Now it’s also interesting when you think about how you learn this because if I ask you at the end of the day, let’s say you were learning to ride a bike, I ask you at the end of the day “what did you learn today?” It can be true that you learned how to ride a bike, you got better at it, you got more practice but you don’t come up with, you don’t have any sort of idea of how to explain it. You don’t say “well today in my bike practice I learned how to apply just enough pressure with my left foot to the pedal and shift my body weight in such a way that I can maintain my balance and also accelerate.” That could very well be what you learned how to do, that could be something you got better at that day but it’s not even in your awareness at all that that’s really what was happening.

All you know is like you felt like it was easier to ride your bike that day. Ok so those are the different types of long-term memories that we have and we see just like with the other boxes you know when we look closely at this sort of simplified model, we look closely at each box, we see there’s actually much more complicated than it first appears. So you might first look at the three box model and think “wow, we really understand memory pretty well, we’ve got this neat little diagram.”

It looks very simple but actually each of those boxes is very complicated and that’s certainly the case with this long-term memory store. Then we ask “well how exactly do they relate to one another? How do we draw things out of our long-term memory into our short-term memory or into our working memory? How do we do that like effortlessly? And we integrate things. Something happens to me and it reminds me of some other memory, how is all of that happening? We don’t really know.

It’s very complicated. And that’s even before we try to figure out the biology of how exactly is this physically happening in our minds? How are neurons making these new connections and how are they storing memories and how are they being retrieved properly? It’s really a mystery and it’s one of these things that the closer we look at it the more we learn about it, it seems all we learn is that it’s actually more complicated than we thought.

So don’t get the idea that just because we’ve covered all of these three boxes now that like you really have this, we have this amazing understanding of how memory functions. It’s really not the case. There’s still a lot of unanswered questions that we have but it gives us a simplification. It allows us to talk about this and sort of identify the area that we understand and the areas that, of course, we need more explanation.

Ok, I hope you found this helpful, if so, please like the video and subscribe to the channel for more.

Thanks for watching!