Tag Archives: short-term memory

A Deer in the Headlights

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Around three o’clock in the morning, I was sleeping in the passenger seat of my boyfriend’s car after a long day of driving. We were on the home-stretch through the forest preserve only a half of a mile away from his parent’s house where we were going to stay. My boyfriend came over a blind hill, only to find a large buck standing in the middle of the unlit road. He slammed on his breaks and swerved to the left, causing my head to slam into the car door with immense force. I was sleeping before this happened, so I was never aware of a deer in the road to begin with, but due to the moderate-to-severe concussion I suffered, I do not recall the events for the hour following the concussion either.

 I do not remember waking up from an unconscious state, crying inconsolably the way a child would. I do not remember my boyfriend trying to calm me down before we pulled up to his parent’s house. I do not remember my boyfriend trying to help me walk into the house because my coordination was impaired, becoming physically ill, or his dad (luckily a medical doctor) waking up to evaluate my situation. I do, however, remember everything leading up to falling asleep in the car. This temporary loss of memory is generally called anterograde amnesia, which refers to the inability to “assimilate or retain new knowledge” (Goldstein, 2011, pp. 149). When dealing with a concussion, or other traumatic brain injury, it is more specifically referred to as anterograde post-traumatic amnesia (National Institution of Neurological Disorders and Stroke, 2015). Part of the reason it is common to lose memory of the concussion and what immediately followed, is due to the fragility of new memories (Goldstein, pp. 193). The newer the memory is, the less time it has had to consolidate (become more permanent), and therefore relies more heavily on the hippocampus for retrieval (Goldstein, 194).

A few days later, my boyfriend was driving me from downtown Chicago to the suburbs where both of our parents live. Originally, we planned to visit both of our families, starting with his and ending with mine. On the ride, I decided just to visit my own parents, and asked if he could drop me off on the way to his, since I was still feeling fairly fatigued from my concussion. We continued down the Eisenhower Expressway for about ten minutes, and he took the exit for Roosevelt Road towards my parent’s house. Confused, I quickly responded “Wait! Why are you taking this exit? This is not the way to your Mom’s house.” I had completely forgotten that I had asked to be dropped off at my family’s house. My short-term memory had also been affected.

When I hit my head, my frontal lobe was the part of my brain that endured the trauma. Usually trauma to the prefrontal cortex affects the ability to control attention through the central executive, which controls and coordinates which information is processed through the phonological loop or the visuospatial sketch pad on its way to long term memory (Goldstein, 2013, pp. 136). We had agreed to visit his family first and discussed it a few times before I decided differently in the car. When I was surprised by the change of route, it was an effect of preservation (Goldstein, pp. 136). Had I been in control of the car, we would have followed the old plans and I would have driven to the undesired destination. Essentially, the concussion inhibited my prefrontal cortex’s ability to briefly hold information.

Lia Stoffle

Sources:

Goldstein, E. B. (2011). Cognitive Psychology Connecting Mind, Research, and Everyday Experience. Belmont, CA: Wadsworth.

National Institute of Neurological Disorders and Stroke. (2015). Traumatic Brain Injury: Hope Through Research. (NIH Publication No. 02-2478). Bethesda, MD: Author. Retrieved from: http://www.ninds.nih.gov/disorders/tbi/detail_tbi.htm#292043218

Short-term Memory and Work Performance

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For this blog post, I will discuss short-term memory and how it pertains to my previous experience in the military. While working in Afghanistan, I was constantly required to receive and report the specific grid coordinates of individuals or events. Depending on the length of the grid coordinates, they could be difficult to report accurately. The capacity and duration of short-term memory and the use of chunking to expand the capacity did have an effect on my job performance.

In lesson 5 of this course, we learned that George Miller discovered what he believed to be the capacity of short-term memory. This capacity was 7 +/- 2 items (Miller, 1956). This means that on average, one is able to memorize and recall 7 +/- 2 specific items at any given time. I do agree with this suggestion based on my own experience. The Military Grid Reference System (MGRS) uses a header for each location that denotes the general area in which to find the grid points. An example header would be 15P SU. Following the header, there would be a four-digit, six-digit, eight-digit, or ten-digit grid point, with the longer grid points being more accurate. Due to the capacity of short-term memory, the four-digit and six-digit grid points were usually simple to recall, and longer grid points did prove to be more difficult. While attempting to recall longer grid points, I often had to report half of the grid and reference the grid again before reporting the second half.

I also noticed that chunking was very helpful if the number sequences held any significance. For example, 15P SU 1776 2001 would be easier to recall than 15P SU 5476 8729. This is because 1776 and 2001 become only two separate items instead of eight separate items, but 5476 and 8729 are number sequences which hold no significance for me, so I would have to recall each number individually.

Furthermore, it has been suggested that short-term memory usually has a duration of 15-30 seconds. This means that even if a sequence of numbers is initially memorized, that memory may diminish over a very short period of time. I experienced this quite often as well. While it was simple to recall a memorized grid point during the few seconds that it took to report it over a message board on the computer, it was much more difficult to recall the same grid point only a minute or two later when attempting to report it over the radio or to the commander. Therefore, it was most efficient to document the grid points for future reference.

The use of short-term memory was constant during my military career, and knowing the limits of short-term memory can be crucial when dealing with important tasks, such as reporting accurate grid coordinates. Many experiments have been conducted in the past in order to study the capabilities and processes of memory in humans. After learning about the results of these studies and comparing them to personal experiences, I believe that they are relatively accurate, and I have gained a more thorough understanding of the cognitive processes involved with memory.

 

Reference

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81.