Memory and Forgetting

Video Transcription

Hello class, so as we all know, memory isn't necessarily perfect. Sometimes we don't remember things well, and we forget things that we had thought we had previously learned. So forgetting means literally not remembering, or in other words, not being able to retrieve information from a person's memory.

So if you recall, there are two types of memory. We have short-term memory and long-term memory. With short-term memory, it's meant to store information in small amounts for short periods of time.

In other words, you know, a few pieces of information for only a few seconds. So in other words, forgetting is part of the process of short-term memory. Any kind of information that we want to remember further doesn't say in our short-term memory, rather, it goes into our long-term memory.

Now we can keep information for longer in our short-term memory if we repeat or rehearse it. Which is to say we put it back inside of our short-term memory, so it can be kept again for several seconds further, or unless we repeat or rehearse it again. But unless it's encoded and stored in the long-term memory, it's forgotten.

OK, so usually when we say forgetting something, we're referring to losing it from our long-term memory. So how does this work exactly? Well, a psychologist named Hermann Ebbinhaus performed some of the first psychological experiments on memory and on forgetting in 1885.

And he tested his own memory in trying to memorize these three letter, sort of, nonsense syllables. Things like w-o-l, or wol, or g-e-x, or gex. So things that didn't normally make any kind of sense.

So he tested to see how he would be able to remember them over different periods of time. And what he did was he created the Curve of Forgetting, and this is something that we use still to understand how forgetting works. It shows that people begin to immediately forget information up to a few minutes, and even a few hours, afterwards.

So you see, there's a drastic change in how much we remember within a relatively short period of time, this is less than a day. So within a day or two, it starts to level off a bit until about six days, which is where it basically levels off at around 30% for these nonsense syllables that he's learning. And after that, it remains relatively stable.

So what we learned from this is that yes, we do forget things generally within a short period of time more quickly. But those pieces of information that enter our long-term memory after that six day, sort of, period becomes relatively stable. In other words, our long-term memory is almost permanent, in certain ways. Especially with meaningful information, not these nonsense syllables we're trying to learn.

The amount of information that can be retained is actually even higher than 30%, and it can be a lot more stable. So why do we actually forget? Well, psychologists have found that there are several different reasons, and they relate to the process of creating memories in the first place.

So if you recall, memory, creating memories, means first encoding the information so that we can understand it, then storing that information in our brains, and finally retrieving it later for usage. OK, so first, an encoding failure means an inability to actually form the memory in the first place, and to put it within our long-term memory. In an experiment done by Nickerson and Adams, some people were asked to identify what a penny actually looks like, out of a series of fake images with one correct one.

They found it was difficult, because we don't pay attention to a lot of the details that make up a penny. For example, which direction Lincoln's head is facing, or where the information is placed on either side of him. OK, we only encode the things that we need to actually remember, what a penny basically is, and how it's different from other coins.

So in other words, that's an encoding failure, because we don't actually pay attention to those things. Also, the idea of use it or lose it is also true for memory, as well. So when memory is formed, when we actually encode it into our storage, we create what are called memory traces, which are these new connections and changes within the neurons of our brains.

So Decay Theory says that over time, these connections begin to fade and go away unless they're repeated or rehearsed. In other words, unless we use that memory in some way, eventually it'll disappear from our long-term memory. This creates what we call a storage failure, but a lot of memories stay with us for a longer period of time.

So Decay Theory isn't absolute. Sometimes we can remember things from our childhood that we haven't thought about for a very long time. So Decay Theory isn't absolute, doesn't explain everything about forgetting.

Next, we have a Retrieval Failure, which is when there can be some interference, or in other words, when certain memories, either new or old, can compete with each other and make it difficult to remember specific information that we have. So in other words, we're not able to access those memories within our mind, because other ones are getting in the way.

OK, so that can be a difficulty in retrieving information that we actually do have stored in our brains. And finally, we can intentionally forget memories, which is to say we can either consciously, by suppressing the information, or unconsciously, by repressing the memories. We can make ourselves not remember those kinds of pieces of information.

And this can apply especially to very unhappy or unpleasant memories from different periods of our life that we want to forget, or that we unconsciously, without even realizing it, put back into our memory storage. So it's still there, but it's something that we don't want to think about.