Despite the vast amount of information that we know, there is a surprising lack of information regarding the brain and how it works. At the very least we can agree that it is widely accepted knowledge that the brain is the only organ to have named itself. That being said, we still have a very long way to go before we completely understand our think tanks. The study of memory is one of those intricacies of the brain which I expect we will all learn much more about in the very near future.
Memory is what humans use to hold on to information from the past. Important dates, ideas, and the number of surrounding cars around you while driving are all stored in either long, short, sensory or-as some are now saying-middle term memory.
Sensory memory is immediate.
This lasts for only a couple seconds at the most. Sensory memory acts a buffer between all information input from the senses. After making an impression the sensory information is carried to the short term memory for processing.
Short term (active) memory
The idea of short term memory simply means that you are retaining information for a short period of time without creating the neural mechanisms for later recall (e.g., obtaining and using a phone number from Directory Assistance.)
These memories are quick in and quick out. The brain decides whether or not remembering Jerry’s yellow bow tie is important information. If it isn’t important, it quickly forgets because the short term memory doesn’t really have a lot of room for holding information. If the brain decides “hey I like Jerry’s bow tie, I should take a second to remember that for later use,” then the brain’s long term memory will encode and store the memory.
Most adults can store between 5 and 9 items in their short-term memory. This idea was put forward by Miller (1956) and he called it the magic number 7. He though that short term memory could hold 7 (plus or minus 2 items) because it only had a certain number of “slots” in which items could be stored.
Short term memory is the ground floor for remembering any type of information. Another, more specific name for short term memory is ‘working memory.’ This puts more emphasis on its importance. Working memory does a lot more work than we are accustomed to giving it credit for. Here’s a nifty chart:
The phonological loop is assumed to be responsible for the manipulation of speech based information, whereas the visuo–spatial sketchpad is assumed to by responsible for manipulating visual images.
In this model, the working memory is expanded to an active process which prioritizes information storage and retrieval. The central executive acts as the President of your memory. While you’re piloting your jet plane and having a conversation with your copilot about after-flight dinning plans, the central executive is prepared to switch your focus when turbulence rears its not-yet-existent face.
The central executive function works with the long term memory to encode and retrieve important memories. The long term memory can be broken down into three specific types of memory.
Episodic Memory
As its name suggests, this aspect of memory organizes information around episodes in our lives. When we try to recall the information, we attempt to reconstruct these episodes by picturing the events in our minds. Episodic memory enables us to recall not only events, but also information related to those events.
Think episodes of information. Remember that one time when you and your siblings…, the other time when one of your parents was chasing a…, or, my favorite, when your first grade teacher gave you a compliment on your haircut but you thought it was on your sweet Power Rangers sweater and you were mildly offended at her lack of taste which resulted in you never learning how to avoid a run-on sentence because, of course, that was what you were learning in class one day (deep breath).. Remember?!
Episodic memory stores information about images and events for later recall. These are the stories that you remember and can see in your mind.
Semantic Network Model
While episodic memory stores information as images, semantic memory stores information in networks or schemata. Information is most easily stored in semantic memory when it is meaningful – that is, easily related to existing, well-established schemata.
Semantic memory and episodic memory feed off of each other. You learn everything through experience so it would be silly to say that the two are independent. The primary difference between the two modes of information remembrance is that while episodic memory remembers the picture of events, semantic memory remembers the facts.
Semantic memory is a web of related memories. Try this: Think of a color. What do you immediately associate with that color?
I chose green. My immediate associations were: leaves, trees, grass, money, banks, pants, corporations, jail, and the presidential office. How these things are connected is the result of a lifetimes worth of associating different ideas with other different ideas. It really is a procedural sort of thing.
Procedural Memory
Procedural memory (“knowing how”) is the unconscious memory of skills and how to do things, particularly the use of objects or movements of the body, such as playing a guitar or riding a bike. It is composed of automatic sensorimotor behaviours that are so deeply embedded that we are no longer aware of them, and, once learned, these “body memories” allow us to carry out ordinary motor actions automatically.
Whether or not american children believe in the one true god, they-myself included- have been trained to know the pledge of allegiance. We have such a working knowledge of saying the pledge of allegiance that we could drone it in our sleep.
This is exactly what procedural memory is. It’s “muscle memory.” You do something so many times that you don’t think that you’re thinking about doing it anymore. (Try that one out, Bilbo).
How Sleep plays a role:
Sleep is vital to the process of storing memories. When you sleep, the amount of sensory input decreases dramatically. This decrease allows both your brain and your body to do a bit of house keeping. Memory, specifically, uses this time to protect and store as much information as possible.
We still understand very little of the brain’s inner workings. Entire philosophies, religions, cults, and other communities are designed in various ways to figure out and improve how the tock clicks- Maybe it’s the other way.
As this is a constantly developing field of research, this information will probably act as a stepping stone to further understanding how memory storage works.
If you have any links or information related to this post, we informationaholics at Wondergressive would love to read about it. You can comment, email, write a letter to your congress person, or even send a message in a bottle telling us what you know! Oh, and, without looking, can you remember what color the bow tie was?
Sources:
Lecture slides from Anoka Ramsey Community college
Other Wondergressive Links:
Wondergressive 