Components of working memory: phonological loop, sketchpad, and executive function

¶ … 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 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.

Such an epiphany has occurred to many a number of times when I have made an etymological connection between a word that I am learning in one language (say, French), and another language (for example, English). For example, the word "mason" has a French cognate -- "macon" (with a cedilla). The words look different, although they sounds similar. One day I was looking at the word "macon" and all of a sudden I saw that the two words were really the same. I made a new connection between two known facts -- and that formation of the connection creates that sensation of an epiphany.

Question Eight:

The Wason Selection task requires a subject to make a logical choice to determine which of a possible set of combinations is true. The key to the task is to remember that certain conditions have to be met at the same time (that is, simultaneously) rather than sequentially or separately. This is easy to do in retrospect, but it is all-too-easy to overlook when one is actually taking the test. Because it seems like such an easy task one does not realize that one actually has to pay some attention to what is going on to make sure that one does not many an easy mistake.

Selective attention is the tendency of an individual to pay attention only to those aspects of his or her environment that accord with already established beliefs, ideas, or knowledge. This is directly related to the way in which stereotypes work and are maintained. For example, if one believes that blacks are more likely than whites to be criminals, one will remember a news story about a black bank officer who has embezzled funds and ignore the far larger number of white bank officials who commit fraud on a much greater scale.

This is also related to the concept of illusory correlation, which is the tendency for an individual to see a connection or relationship between or among a set of experiences, objects, etc. even when there is no real connection, causation, or correlation. The above example with the bank officers could also serve as an example of illusory correlation.