Working Memory (WM) is hard to track down and manipulate. We fill it up and empty it out so rapidly we don't even know it. We go from map to walking so fast, we calculate out a tip, we figure out what time our laundry will be out of the dryer, we read a paragraph and absorb the message of a book so quickly. So why bother studying it?
Like many things in life, a small thing like WM has prfound implications. It has generally been isolated in the DorsoLateral Pre-Frontal Cortex (DLPFC) with a few other locations in the Temporal Lobe. In people with DLPFC damage, they are unable to remember how they got where they got where they were, or what you just said; their long-term memory, however, remains intact.
In a nutshell, without WM, we can't really function as a human is expected. We can't talk complexly, we can't do basic math. Hypothetically, and generally speaking, of course.
How does it tie into language? Remember (ha ha!) in my last entry, I discussed how there were three components of working memory? They were the phonological loop, the visuo-spatial sketchpad and the central executive. The phonological loop is a cache that takes in all the language data and sends it to the central executive. The central executive then decides what to do next: look up a definition from your 11th grade english class, keep listening for further context, respond with physiological responses in the fight or flight. The phonological loop takes care of the reading, as well as the verbal.
To remember an item, there is a slight corrolary that has been dubbed the "articulatory loop" in which you are remembering an item by rehearsing it, such as that pesky phone number, or address, or username on MySpace. When you rehearse in your head "soccergrrl28, soccergrrl28" until you can type it in, that's the articulatory loop in effect.
These are important for my Div3 in a variety of ways. One half of my Div3 is dedicated towards a Reading Span task which relies on both articulatory loop and the phonological loop. The Reading Span Task (see Daneman and Carpenter, 1980) requires people to read sentences one at a time, and remember the last word of the sentences they were presented. These are presented in 2 to 6 sentence chunks. What it does is make the articulatory loop work, while the phonological loop is trying to work and shove new information in it. Some people are very good at this and they are known as "high span" people. Most college students, I've found, have a high span. I would have preffered a community sample, but what can you do?
This little find, that people have an individual difference in their working memory capacity and ability to manipulate that information, has had a ripple effect in the psycholinguistic field. It has been shown that the verbal WM (as the span task shows) is separate from mathematical working memory and serial recall (Shah and Miyake, 1996). Language, it seems, is a bit more hardwired in the brain than we give ourselves credit. It also used to be thought that everyone had the same capacity (6 digits, I think). But now it is inidividualized.
Why is this part of my Div3? The ability to manipulate language in whatever center of the brain that it's doing it in has several implications. People with higher WM capacities can untangle verbal knots faster, acquire vocabulary faster (but not better), and figure out sentence context better. The aforementioned generally are all related.
So, since what I'm presenting on screen is presented one word at a time, these words need to be held in working memory until they are dumped out. It was hypothesized that children don't have the ability to create sentence context the way adults do, and that is why their N400 is smaller than in adult subjects. But I think that's all for a later post.
At the present, I'm still parsing out what I mean. It makes total sense in my head how this is all related, but I can't even get a bubble-chart out at the moment. When I do, you'll be the third to know.
Daneman, M., Carpenter PA., (1980) Individual Differences in Working Memory Journal of Verbal Learning and Verbal Behavior
Gathercole, SE., Baddeley, AD (1993) Working Memory and Language. Erlbaum and Associates: Hillsdale.
Shah, P., Miyake A., (1996) The Separability of Working Memory Resources for Spatial Thinking and Language Processing Journal of Experimental Psychology:General 125(1) 4-27
MacDonald, MC., Just, MA., Carpenter, PA (1992) Working Memory Constraints on the Processing of Syntactic Ambiguity Cognitive Psychology Jan(24)1 56-98