Components of Working Memory Working

¶ … Components of Working Memory

Working memory includes elements that can be characterized as the phonological loop, the visuospatial sketchpad, and the central executive function. The phonological loop -- which is also called the phonetic or articulatory loop -- rehearses verbal (or aural) information. Short-term phonological memory tracks memories that are subject to rapid decay and the articulatory rehearsal component, that is used to revive decayed memories. The visuospatial sketchpad is the aspect of memory that maintains visual and spatial memory and that provides the basis for visualization and certain kinds of calculation as well as for optical memory itself. The central executive function of memory coordinates memories that arise from different types of sensory and cognitive experiences.

Working memory is a limited capacity system in that there are clear physical limitations to the amount of information that can be recalled at the same time -- something like an old-fashioned telephone exchange that is trying to funnel a number of different calls at the same time. Each aspect of memory has a certain amount of capacity as well as there being an overall limit (kind of like the space left over after a full meal in the "dessert stomach"). As a result, it is harder to recall two visual memories than a visual memory and an aural or verbal memory.

One can test this fact for oneself. Try to recall a birthday party: One can see what is going on and hear the "Happy Birthday" song as well. Now try to recall that song along with a song you heard this morning on the radio. This second task is much, much harder -- even impossible. The system is overloaded and crashes.

Question Two: Memory and Learning

Without admitting any guilt, it is just possible that I have once or twice not gotten a full eight hours' worth of sleep the night before a major test. And -- just like all of the other students who have done this since the first university was founded over a millennium ago -- I have convinced myself that this was exactly the right thing to do. After all -- wouldn't be a waste of time and potential not to study up to the very last moment?

Well, no. Learning is, of course, an incredibly important skill for students (as well as for humans as a species), but it is only effective when paired with memory. Taking in new information that does not become lodged in memory and so accessible to an individual at a later point is not productive. Therefore it is imperative to learn material in such a way that it can be memorized if one wants to succeed on a test (or in any other activity). Indeed, learning can be seen as a form of memorization.

A large body of research on sleep has demonstrated that new information that has been learned does not become available to the individual until after six to eight hours of sleep. This amount of time seems to be required to allow the brain to sort the new information and file it into the appropriate slots alongside information that has already been learned and internally organized.

This knowledge tells one not to study all night before a test. However, it would still be effective to stay up all night writing a paper before turning it in and then going to bed for the rest of the day!

Question Three: Constructive Memory

The exercises and readings that we have done for this class have convincingly to me that memory is indeed constructive. It is much more like Photoshop than a Polaroid. Just as a Photoshop image (usually) begins with something real -- something that people can agree exists in the world at large -- memory begins with something in the objective world that a person takes in through his or her senses. But then that original event or image that existed in the world becomes shaped by a person's internal mental processes.

This is something that makes sense, because each of us is aware of the fact that different people have different memories of the same experiences. For example, I have often been struck by how I will talk about a movie that I have just seen with some friends of mine and how different their memory (and understanding) of it is compared to my own memory. This had never bothered me because such differing memories are what makes life interesting: As unique individuals it seems appropriate to me (and beyond appropriate to good) that we should each have unique memories that record unique experiences.

However -- and this is something that I had never considered before -- such differences in memory can have terrible consequences in certain context, such as with eyewitness testimony. This is the lesson that I take away: Memory is constructive, and this fact is neither good nor bad, simply true. But given how much memory is the product of what happens inside our heads rather than in the world outside, I will always remember to think of my memories as having been unwittingly Photoshopped by my own brain.

Question Four: Classification

Classification is an essential part of human cognition. Indeed, I would argue that it is perhaps the very most important thing that we do as humans. If one has ever watched a baby or toddler playing with basic toys like blocks, one will notice that young children spend a great deal of their time dividing objects into categories. They will put all of the blue blocks together, or all of the triangles together, or everything made of wood together. Clearly what they are doing (even at a pre-verbal stage) is classifying their world.

That this should be such a fundamental task for young children should not in any way be surprising because the ability to classify the things in our world has very clear evolutionary value. The person (or Homo erectus individual) who can correctly classify a mushroom as edible as opposed to toxic (and the reverse) will live to pass on her genes. Likewise, a person who can correctly classify another individual running towards her as an enemy rather than a friend will also have a much better chance of surviving.

Brain damage can disrupt a wide range of normal classification activities, including being unable to recognize a known person unless one meets that person in an expected location and context. People with brain damage often have a wide range of language tasks, such as the inability to say the name of an object, even when they are capable of pointing out the object. While such problems tend to be classified as problems with language rather than with classification per se, language as a skill is based in the ability (and need) of humans to classify and categorize their world.

Question Five: Familiar Object

(Image at http://www.sydneywildlife.org.au/birds/cockatoo.html -- the first picture at this website).

This is a picture of a bird with short white feathers all over its body and a crest of spiky lemony yellow feathers on the top of her head. Her beak is black and halfway between matte and shiny. Her eyes also appear to be black, but they might also be dark brown. Her feet are greyish-black and ribbed looking. They make it clear that birds are the clear descendants of dinosaurs because they seem very strong. She is using her feet to hold onto a branch. The branch has no leaves and is about the color and texture of the bird's feet. The bird is looking up slightly and seems to be very attentive to her surroundings, as if she were either looking around for something to eat or -- conversely -- looking around to make sure that there is nothing interested in eating her.

Propositional (or verbal) representations are language based. They are therefore symbolic, relying on our human ability to extrapolate from both the information provided by words and the interstices between them. Propositional representations require the ability to abstract to make them usable. Depictive representations are "real" -- that is, they resemble something in the world. This does not mean that we do not bring to our interpretation and understanding of depictive representations our own mental concepts. Verbal representations allow us to use more of our own experiences to fill in the blanks in the description, but even when presented with a photograph we still personalize and interpret what we see.

Question Six: Word Articulation

I believe that one's ability to distinguish the breaks between words (or, to put it another way, the words themselves) in a language that one does not speak depends in some measure on one's linguistic abilities. Certainly it is harder to hear the breaks in a language that one does not speak, and this is probably more true the further the language is from one's native language. (for example, a native speaker of Spanish would probably find it easier to distinguish the words in Italian, even if she does not speak it, than she would be able to distinguish the words in Mandarin.)

When listening to the video for this exercise, I cannot hear the different words: The sounds seem nearly continuous (although I can hear the speaker take breaths). However, it is also true that simply because I cannot distinguish the words being spoken here does not mean that other people could not. Some people are linguistically incredibly gifted and I believe that they might be much better than I am at distinguishing word segmentation, especially at recognizing the phonetic clues that signal the beginning of a new word.

In the video of the McGurk Effect, I hear the man saying "ba." I continue to hear this no matter what combination of seeing and listening I apply. The illusion -- the mismatch between sound and hearing -- results from the fact that we combine visual and auditory cues in decoding speech.

Question Seven: The Aha! Moment

Surely everyone has had the experience at least once of suddenly seeing something that was not clear before. For myself, this has most often occurred in the context of math and science. Indeed, one of the archetypal "aha!" moments comes from the history of science as Archimedes is said to have leaped out of suddenly over-flowing bathtub and shouted "Eureka!" when, in an instant, he understood the connection between displacement and mass.

This same experience is repeated time and again as a student wakes up and looks at a math problem that was impossible to solve the night before, only to find it transparently easy the next day. Of course, the problem is not actually easier, nor have we become magically smarter overnight. Rather, our brain has been able to reconfigure the information that we have in a way that it makes sense. In some ways, one can compare this process to the process of decoding an encrypted message: Once we have the key, the message is clear.