Do all of our cognitive processes withdraw from the same cognitive bank? How is it that we are able to drive a car, chew gum, talk on the phone and listen to music all at once? Is it possible that our mental resources are somehow specialized in such a way so that different tasked are allocated different resources at different strengths? Our brain is unfathomable in it’s ability distribute responsibility to different regions and the storage of it’s memory will and can never be known. With technology many questions are being answered and with regards to divided attention. Brain imaging techniques such as the PET scan uses 2-deoxyglucose, which is injected into the patient’s carotid artery. Because of its similarity to glucose (brain fuel) it is absorbed by active energy consuming neurons. Fortunately this form of glucose derivative does not become metabolized hence giving us the researcher the ability to tell where the activity is located with a precision of a few millimeters. The PET scan was at on time the only tool used to find the location of neurological processes but now they have fMRI, which is less time consuming and less messy. With these imaging tools, the use of the computerized tachistoscope and the educated inferences by highly educated individuals we are getting closer to understanding the brain and the complex web of processes present in divided attention.
There are two theories that try to explain the phenomena of divided attention. The first states that all tasks are basically the same in regards to where they obtain their resources. The second calls for a more complex task-specific resource pool. General resource theory states no matter what the nature of the tasks are they all compete for the same limited pool of resources. With this theory in mind all we need to be concerned with is the resource demand, the combined cost of all the individual tasks at hand. If the combined demand for the tasks is greater than the available resources a task will suffer due to interference. Task-specific theory states that two tasks will interfere with each other only if the two tasks are similar hence pulling from the same source. If the tasks are different, using different cognitive abilities i.e. Spatial vs. verbal, then divided attention will be easy because the two processes take place in different regions of the brain hence pulling from two resource pools rather than just one which in turn explains divided attention. Many studies prove this to be true and all conclude the degree of interference depends on the nature of the tasks being performed.
Working memory has its limitations and divided attention can only be so “divided”. Cognitive processes take effort and there is some times a tie up on the neurological super highway because of the time required to put forth that effort. The way our brain deals with these little tie-ups is a response-selector. A response-selector can only deal with on thing at a time, just like a waiter can only take one person’s order at a time. If two consecutive tasks require the response-selector one ends up waiting while the selector deals with the other task. Most tasks do not require a constant aid of the response-selector so you may select and then initiate an action and the time you spend carrying out that action frees up the response-selector to take on another task, come up with a solution and then initiate the response for that task. This process is a cycle where response-selector bounces from task to task this is commonly referred to as time-sharing and is evidence that divided attention is also task-general.
In everyday life I myself find that I rely on divided attention a lot. Most of my divided attention can be explained by automaticity. For example I work at Blockbuster Video as my off campus job and I find the job very easy due to practice. Most of my shift is spent on auto pilot which frees up my resources to be able to make conversation with my fellow employees but most often with customers giving them my reviews on movies I have seen. Performing tasks on the computer that at one time took total concentration with practice have become actions I could do with my eyes closed. I have noticed although a problem with divided attention I tried out for a play for the first time this semester and I did not realize how difficult it was to do a “cold read”, reading lines that are unfamiliar and given no instruction on proper dictation. I found my self competing for resources when I went up to read my lines and found my self not only trying to read what was on the page, but also trying to adjust my tone of voice to parallel what was being said and adjust my body movements in attempt to look natural.
I had a vague idea of how divided attention worked but no where close to the understanding I have now. I feel that I understand divided attention very well because I was able to torture my roommate with a detailed explanation of it three in the morning enough so he became interested in what other knowledge I have obtained from this class.
The Role of Meaning and Memory Connections
Obtaining new knowledge requires learning and input of new material into long term memory. For the new information to become new knowledge one must understand the information and interrelate it with past knowledge or weave it in with other chunks of information to be entered into the brains storage unit refereed to as long term memory. An intricate indexing procedure is needed in order to retrieve this information for latter use. According to the parallel distributed theory of learning an idea is stored not as one unit but rather many sub-units all connected due to there related meaning. Connections allow one memory to trigger another and through the spreading activation of neurons complex webs of understanding are accomplished. This is very convenient because if any part of the material is recalled then that recall of information connected to it is more easily recalled. We memorize information so much more easily if we are able to see the whole picture and understand it to the extent that we are able to organize it. Organizing material makes learning easier because by understanding something it reduces the amount of information to be remembered. That is because we think of the elements of an idea as constituents in an interconnected whole. We then enter the package whole into memory rather than it’s separate components. By integrating and unifying the information with past knowledge it reduces the effort needed to remember whatever information needs to be learned.
With this knowledge at hand I have finally answered a question I have tormented my grade school teachers with; “why do we have to know this?” I would have liked an educated answer back then but unfortunately it was not offered. I now know that the knowledge I obtained from grade school set forth a foundation for my knowledge I obtained in high school which in turn built a layer for my understanding of material I am learning in college.
I found this topic of state dependent memory very interesting. I did have a vague understanding of state dependent memory; it wasn’t till I read the detailed description of it in our book that I really grasped the idea. I was able to interrelate it possibly with a psychological disorder called post-traumatic stress disorder in soldiers and the problems with coming back to civilian life. After reading the text I speculated that state dependent memory of wartime events could be triggered if a stimulus was to be generalized in some fashion to a stimulus present in a war environment. My best friend’s dad was in Vietnam and suffers from post traumatic stress disorder I have spent countless nights drinking with him listening to his stories and firing questions. He has told me his war time memories in such detail I am going to use them in some shape or fashion to write a book. He has told be that when he gets really stressed out he loses awareness and is in battle again. I believe that the stress is the connected state dependent memory. He is able to relive the horrible torment of war only in the presents of extreme stress since those memories were entered into his long -term memory during that emotional state.
Further evidence of state dependent memory is how I seem to recall information so much better and quicker when I have a cup of coffee. This is because there is not a night that goes buy that I don’t have a cup of coffee when I’m studying. The coffee must effect me on a multitude of levels including olfactory and taste not to mention the arousal of mood experienced by the caffeine.
I found the texts explanation of how eyewitness testimony could be tainted with errors very interesting yet at the same time very disturbing. I found it interesting how old information could become entangled with new information and perceived as the actual event even though the new information was obtained later. Both pieces of information were integrated into a whole. I also found it interesting how the manipulation of an adjective could change ones perception of an event. People draw inferences on a wide variety of things and will assume the presence of an object even if it is not there. Eyewitness testimony has been the key factor in putting many innocent men and women behind bars. Prosecutors know the tricks of the trade and by choosing there questions and carefully picking there adjectives they can get the eyewitness to make statements that are total lies or exaggerations of the truth and in most cases the witness is not aware of the reality of the truth. Leading an eyewitness with certain questions consumes a majority of the opposition’s objections. I also saw a 20/20 episode where a guy when into room with a bunch of kids while being observed by researchers in a two way mirror, he played with the children read them a story and maybe rough housed with them a bit. Some of the children were simply asked what the man did and they answered accurately to the actual event the other children were asked leading questions and asked if they remembered the man touching them. At what point did you feel uncomfortable when he touched you? What did he do that made you feel uncomfortable? The first time around most of the kids told the truth. A week later after being primed about unacceptable touching the children came up with some remarkable statements shocking and unbelievable, so unbelievable I still suspend the validity of that particular piece.
Activation Levels and Response threshold
The fact that some neurons are easier to activate than others interests me but from a biological standpoint I am confused. I know that the resting potential of a neuron is -70mv and when activated it jumps to +50mv. The firing of neurons in my understanding has to do with mainly the charged isotopes sodium and potassium passing in and out of “pumps” or channels which then send an weak electric impulse down the neurons axon which is covered by the myelin sheath which is a phospholipid bi-layer that acts as a semi-conductor hence allowing the weak impulse to travel great distances in the neuro-network. I also know that an excited neuron decreases its charge quite quickly. What I don’t understand is how different detectors have different response thresholds. The book explains it’s self well I just need to some how better parallel this knowledge with my biological knowledge therefore giving me a more concrete understanding. It says that detectors that have fired recently will have a higher baseline level. What time frame are we talking here? How many msec? It also says detectors that have fired frequently in the past will gradually gain a higher and higher baseline level. Is this because of more dense connections? The strengthening of connection? How does this occur? I do understand their explanation of these phenomena when it comes to priming, but in other facets I do not.