Introduction to Memory

When I look back on my childhood or I remember some words from Spanish or from Russian, Здравствуйте, or I bring to mind one of Maxwell’s equations, I’m drawing on portions of my brain involved in long term memory. But what I’m trying to hold a few ideas in mind to connect them together so I can understand a concept or solve a problem, I’m using my working memory. Obviously, sometimes I’ll bring something from my long term memory into my working memory, so I can think about it. So the two types of memory are related. There are lots of different ways to slice our understanding a memory, but for this course on learning, we’re going to talk about only these two major memory systems, working memory and long term memory. Working memory is the part of memory that has to do with what you’re immediately and consciously processing in your mind. Your working memory is centered out of the prefrontal cortex, although as we’ll see later, there are also connections to other parts of your brain ,so you can access long term memories. Researchers used to think that our working memory could hold around seven items or chunks, but now it’s widely believed that the working memory is holds only about four chunks of information. We tend to automatically group memory items in to chunks so it seems our working memory is bigger than it actually is. Although your working memory is like a blackboard, it’s not a very good blackboard. You often need to keep repeating what you are trying to work with so it’s stays in your working memory. For example, you’ll sometimes repeat a phone number to yourself until you have a chance to write it down. Repetition’s needed so that your metabolic vampires, that is, natural dissipating processes, don’t suck those memories away. You may find yourself shutting yours eyes to keep any other items from intruding into the limited slots of your working memory as you concentrate. So we know that short term memory is something like an inefficient mental blackboard. The other form of memory, long term memory, is like a storage warehouse. And just like a warehouse, it’s distributed over a big area. Different kinds of long term memories are stored in different regions of the brain. Research has shown when you first try to put a short term memory in long term memory, you need to revisit it at least a few times to increase the chances that you’ll be able to find later when you might need it. The long term memory storage warehouse is immense. It’s got room for billions of items. In fact, there can be so many items they can bury each other, so it can be difficult for you to find the information you need unless you practice and repeat at least a few times. Long term memory is important because it’s where you store fundamental concepts and techniques that are often involved in whatever you’re learning about. When you encounter something new, you often use your working memory to handle it. If you want to move that information into your long term memory, it often takes time and practice. To help with this process, use a technique called spaced repetition. This technique involves repeating what you’re trying to retain, but what you want to do is space this repetition out. Repeating a new vocabulary word or a problem solving technique, for example, over a number of days. Extending your practice over several days does make a difference. Research has shown that if you try to glue things into your memory by repeating something 20 times in one evening, for example, it won’t stick nearly as well as if you practice it the same number of times over several days. This is like building the brick wall we saw earlier. If you don’t leave time for the mortar to dry, that is, time for the synoptic connections to form and strengthen, you won’t have a very good structure. And talk about lasting structure, look at this part of the Acropolis here. Thanks for learning about learning. I’m Barbara Oakley. [BLANK AUDIO]