Short-Term Memory Part II: Working Memory

Last week we ventured into the short-term memory section of the information processing model and talked specifically about primary memory, which is about the registration of information. Primary memory is used to remember information just as it is presented. Things like phone numbers and addresses are held in primary memory. This week we’re looking at working memory.

So what exactly is working memory? Working memory is used for the manipulation of information. When you perform mental arithmetic, you’re using your working memory to do calculations, carry numbers, and produce a solution. One of the classic working memory tests in psychology is the venerable reverse digit span. I tell you a string of digits and ask you to repeat them back to me in reverse order, so if I say 3-7-1, you say 1-7-3. Another common working memory task is the n-back exercise. Suppose I shuffle up a deck of cards and show you the top card, which is the jack of clubs, and I put it face down and show you the next card, which is the three of hearts. In a 1-back exercise, when you see the three of hearts, you’d tell me what card was 1 before (1 back) the card you’re looking out. When I flip the next card, you’d say three of hearts because it would then be one back from the new card. Two-back exercises are somewhat harder, because you need to recall the card was two before the current card. N-Back—the N is a place holder for the number back that someone is asked to remember—exercises require someone to temporarily hold information in short-term memory, express it, discard it, and then refresh his memory with new information. It’s very challenging.

As you might imagine, working memory facilitates a lot of cognitive functions. Consider the job of foreign language translator—this is a person who listening to someone one language, holds it in her memory temporarily, translates it to another language, expresses it in a grammatically correct form, and then shifts her attention to listen to the response, which she holds in her short-term memory…It’s a demanding working memory task. Research suggests that auditory working memory—memory for things we hear—is related to reading comprehension. Although we look at words, we frequently hear them in our head as we read, and if asked questions about what we’ve read, we tend to skim through that auditory recording in our brain to find the answers. Our visual working memory is frequently linked to math performance. The idea is that we have a sketchpad or a blackboard in our mind’s eye that we use to perform mental calculations.

Research by Patricia Alloway suggests that about 10% of people experience some kind of working memory deficit. Working memory difficulties are associated with academic problems like reading and writing, but also difficulty with planning and organizing. We can externalize most working memory demands--perform math calculations on paper or write all kinds of sticky notes to remind of us different things, but this can be time consuming. The good news is that we have evidence suggesting that through training programs working memory can be improved, and this sometimes leads to improvements in academic performance, or a greater ability to make good use of the academic instruction that is being offered.

Other research shows links between working memory difficulties and mental health problems. People who experience anxiety and depression often have some kind of working memory problem. This isn’t to say that working memory problems are the cause of mental health issues, but there appears to be some kind relationship. Likewise, it doesn’t mean that strengthening working memory is going to help prevent depression and anxiety. It seems more likely that mental health problems compromise working memory capacity, which interferes with problem solving and decision making abilities. This can impact a whole host of issues—academic, occupational, social and interpersonal.

I could spend hours writing about working memory, but this is enough for this week. Next week we can pick up right here and talk some about encoding—the process we use to get information from our short-term memory integrated into our long-term memory.