Well, let's assume that we've encoded the information properly, and now it's time for the second part of the process. We need to write it on the hard drive of our mind. We need to engage in the storage process, and I can tell you that scientists do not fully understand storage, retrieval and . We have a good idea about many the things that influence those processes, but there's still a lot of room for us to learn more about how the process actually happens in the brain. Probably the best model of memory storage has been developed by Atkinson and Shiffrin. We call it a model because again we don't have proof that these principles exactly describe what's happening in the brain. But they seem to be very consistent with what we've learned about the brain and memory. Atkinson and Shiffrin's model poses three stages to the storage process. First, Atkinson and Schiffrin say memory information enters what they call . Sensory memory is a place where it last for a very short period of time, maybe from a quarter to a half a second up to perhaps two seconds long. The trick is if that information is not paid to, while it's in that sensory memory, it will be tossed out. Tossed out, so it will be like the person never knew that information, like . This is why it's very important, when you're trying to remember something, that you go back over what it is you're trying to remember. Going back over it keeps it fresh in sensory memory for that short period of time, and guarantees that it will be sent on to the next level of storage.

The next level of storage is short-term memory. in this place last quite a bit longer, some people say about 20 seconds. Some people say 30 seconds, generally 20 to 30 seconds. The same principle applies to short-term memory, as it does to sensory memory. Once the information gets in short-term memory, if it is not used or paid attention to, then it will begin to be tossed out. But the that is used within that 20 to 30 second time frame will remain in short-term memory. This again is why it's very important to continue to review information. So, from a practical perspective, if you're trying to study for a test, and you are reading the text in a book, what you want to be sure is that as you continue, you think back to what you just read, and consider how does it connect to what you are reading now? What new information is being added? By doing that, you are constantly rehearsing or repeating old information, keeping it alive in short-term memory. The other important thing about short- term memory is that it has a limited. It can only hold seven pieces of information, give or take 2. Some people’s minds hold 9 pieces, some people five pieces. But on average a person can hold seven separate pieces of information in their short-term memory at one time. Now to me this is very limiting, because there are many times in my day when I need to remember more than seven things. But interestingly enough this is one reason that phone numbers are seven digits long, and many of the things that we have to remember, even student IDs at Midlands Tech are seven digits long. That really fits well into short-term memory. but what you do when you're faced with a situation where you have to remember more than seven things at once. In that case you can use what's called chunking. If I were to show you the first line of a list of random letters, and say look at this for 10 seconds, and then close your eyes while repeating what letters you saw, you would probably be able to remember around seven of letters that you saw. But if I asked you to look at a second line of letters, and remember what you saw, you would probably be able to remember the entire line. The interesting thing is that both lines are of course the same letters. The difference is that they are grouped. That grouping is called chunking. Chunking involves taking similar pieces of information and combining them together. So what happens with the second line of text is that instead of having many individual letters that you have to remember, you are actually only remembering six pieces of information, and each piece consists of many different parts. It’s like in the child's game, a Barrel Full of Monkeys, where you toss the plastic monkeys on the floor, and you have to hook one onto another. When we combine things together, it creates chunks, and chunks are so much more efficient ways of remembering things. This applies directly to studying. Just trying to remember a hundred different facts is very difficult. But grouping those facts together under categories or topics makes it much easier to remember.

Now, short-term memory is Atkinson and Shiffrin's way of talking about this stage of the storage process. But Alan Baddeley came along and said that maybe a more accurate name for this part the process would be , because actually work is going on in your brain in this area of storage. What he means is that working memory consists of three separate parts, the phonological rehearsal loop, where information that you hear goes into. Think of it like an inbox on an executive's desk. The visuospatial sketchpad is the second part this. It is an inbox for visual information, for things that you see. The third part is the executive: the executive control system. The job of the executive is to sort through what is in the phonological rehearsal loop and the visuospatial sketchpad, and decide what the person needs, and decide what can be discarded. It is like an executive going through their inboxes, looking to see what pieces of paper they need to keep to be filed away in long-term memory, or what piece of paper contains information that is not really necessary, and will then be tossed out. So this is just another way of talking about short-term memory. But it may be describing more fully the process that goes on in short-term memory.

The last part of the storage processes, of course, is long-term memory. If information is held long enough in short-term memory, it is passed on to long-term memory, and the good news is, once it's there, it will stay there pretty much for the rest of the person's life. Long-term memory is relatively permanent. That doesn't always mean it can be easily retrieved. But what we know is that once it's in there, it will stay over the long haul. The other good thing about long-term memory is it does not have a limited capacity. It has an unlimited capacity. There is no limit to how much information can be put in there. So when we look at the model of storage, we have three parts: sensory memory, working memory, and long-term memory.

What I want you to see is that at any point information that is not used can get tossed out of sensory memory, working memory, and long-term memory. It can also be eliminated because of either damage, or other problems that can develop. Otherwise, once information is stored in long-term memory, it's there until it is needed.

When it is needed, that is the retrieval process. Information is retrieved from long-term memory, and brought back to working memory or short-term memory, where it can then be used or combined with other information to help a person a respond or make decisions. So we've looked at the model of first encoding, and then the model of storage. This completes this lecture on memory.