Short-Term Memory—Part I

The next part of the information processing model that I greatly use as the basis for my evaluations is short-term memory. Things that we pay attention to move into our short-term memory, which is very important, because virtually all of our problem solving and decision making happens in short-term memory. There’s a lot going on in this part of the model, and to do it justice, I’m going to split it into two different blog entries. This week I’m dedicating my attention to a brief overview and some detail about primary memory. Next week, we’ll dive into working memory.

Short-term memory is where we hold and manipulate information to make in the moment decisions. We’ll talk more about problem solving another time, but recognize that it all happens here. When we’re contemplating a problem, we’re holding it in our short-term memory, and when we’re working out a solution for that problem, we may retrieve some experiences or information that we stored in long-term memory for the very purpose of problem solving in the future. Once the whole model is laid out, we’ll discuss in more detail how this happens.

For now, let’s focus on primary memory. Primary memory—sometimes call registration memory—is for holding information just as it is. It’s remembering the combination to your gym locker. It’s remembering names, dates, and addresses. There’s no manipulation of the information—that’s a job for working memory that we’ll discuss next week—primary memory is just for short-term recall of information as it was experienced. Without rehearsing this information or encoding it into our long-term memory, our primary memory will typically last for about 20-30 seconds. Some readers may be old enough to remember looking up a phone number (in a phone book) and repeating it to themselves enough times to dial it into their wall-hung rotary phone and then promptly forgetting it by the time the call was answered. That’s a perfect example of primary memory in action.

You can briefly hold several things in your primary memory. Some people may be familiar with George Miller’s magical number 7 plus or minus 2, which arguably reflects the number of pieces of information—5 to 9 items—that can be held in short-term memory at once. There’s some debate about the true capacity of short-term memory, but most people tend to agree that there is a limit. Most people also agree that we can increase that capacity by chunking things together. For example, remember this six-item shopping list: basil, olive oil, pine nuts, Parmesan cheese, garlic, and linguine. This might tax your primary memory, especially if you needed to reserve some space to remember other things like milk and eggs. However, if you’re familiar with ingredients of pesto—basil, olive oil, pine nuts, Parmesan cheese, garlic, and linguine—you can chunk them together into one category—pesto ingredients—to free up space in your short-term memory for other grocery items, like chocolate.

Primary memory operates in concert with working memory to solve math problems, comprehend things that have been read, plan what will be written, and make any variety of decisions. When primary memory is compromised, it can be very difficult to process information and solve problems, which can make school and work exceptionally hard. Thankfully, there’s plenty of research suggesting that there are strategies to improve our primary (as well as our working) memory. Before we get to those strategies, we’ll need to discuss the rest of the information processing model. I’ll be back next week to pick up with working memory.