Monday, April 5, 2010

March 2010: Learning & Memory Essay

I was sixteen when I learned how to sail. I was part of the crew of a 139-foot Brigantine tall sailing ship off the coast of Massachusetts, and there was a lot I needed to know. I needed to learn the names of thirty different knots and how to tie them with rope. I needed to know the names of all seven sails, and the names of each line attached to them. Though the shapes of the sails vary, each sail was composed of the same parts. The fact that I could learn the names of the parts and apply them to each sail made it easier to learn because the stimuli of the sails and their parts occurred at the same time: co-occurrence, when multiple stimuli are present at the same time, contributes to the stimuli being recognized together. As things that “fire together wire together,” the sail parts became associated with each other in an associative network.

Another element that facilitated my learning of the sail parts and knots was contingency: I quickly learned that the First, Second, and Third Mates would single out student sailors to quiz them on the name of a line or ask them to tie a not. I learned by operant conditioning that if I wanted to accomplish the task correctly in front of all the other 24 students, I had to study my lines and knots and be prepared. I was able to change my behavior to be a good sailor by studying my knots and lines. There was also an element of surprise that helped me commit the sailing terms and procedures to memory. Before we boarded the ship, we had to do small assignments and projects elaborating on the material we would be working with aboard. As it was a sailing research vessel, we would be studying salinity, depth, temperature, and cataloging the types of organisms we found at different longitudes and latitudes during the voyage. To prepare, we went to salt marshes to practice collecting data and it was surprising to enter a new environment and practice new techniques of data collection. Another element of surprise, which activated the amygdala and hippocampus, was when we would practice raising and lowering a mock sail. It was the first time we had to apply the information we learned in the classroom to a real sail, so having to interact with the physical lines was a new situation with an element of surprise.

The two types of learning are classical conditioning and operant conditioning. Classical conditioning describes a predictive relationship between the conditioned stimulus and the conditioned response. My bunk on the lower deck of the ship was very close to the galley, so I could always hear the din of the pots and pans clanking together. When the sound would awake me (serving as the conditioned stimulus), I would then have breakfast (food serving as the unconditioned stimulus) before I went on watch. I started to associate the sound of the loud noises coming from the galley with being fed, so after several days aboard the ship I started getting hungry when I heard the galley noises filling the lower deck. The fact that the sounds coming from the galley could cause me to be hungry is the result of classical conditioning, whereby the conditioned stimulus of the din would predict food by association, so I would be hungry in anticipation of the food (the conditioned response).

Operant conditioning helped me shape my behavior so that it was as beneficial as could be for the situation at sea. I quickly learned that when I was assigned a task aboard (either to be on lookout on the bowsprit, or steering the helm) the whole ship and crew were depending on me to perform my job accurately. There would be negative consequences if I made an error. If I steered the ship too far one way or another (which would be an example of an error or mistake, therefore bad behavior), the sails would not have the optimum amount of wind in them, which would be a negative reinforcer. If I was at the bowsprit on watch and I did not see a boat or piece of land in front of the ship (an example of an error), we could crash and that would be a negative reinforcer. If we had to change the sails and all hands were called to deck and I needed to go to a certain sail, I needed to know exactly which line to haul on, otherwise I would cause problems for every other member of the crew and I would have prevented a successful sail change. The embarrassment that would have resulted from this would have been a negative reinforcer as well. On the other hand, when I hauled on the correct lines and thoroughly executed my tasks, I was filled with a sense of accomplishment and pride. I was rewarded by the fact that I contributed to the wellbeing and safety of everyone aboard the Cowrith Cramer. The feeling of satisfaction and of doing my job properly for the safety of every person on board was a positive reinforcer.

The two kinds of long-term memory are explicit and implicit. Explicit memory is a kind of memory that you are conscious of and can verbalize. Stored by the hippocampus, explicit memory is remembered vividly. The two kinds of explicit memory are declarative / semantic and episodic. Declarative memory is about facts and information. The names of the knots, sails, and parts of the ship would be categorized in my brain under declarative memory. These are also things that can be looked up, due to their factual nature. Episodic memory is personal and fragile: it encompasses experiences that have happened to you. When a memory that is stored as episodic is recalled, it must be reconstructed. These memories are also categorized, which is why when I think back to my time aboard the ship four years ago, even though I was at sea for two weeks, every day seems to blend together in my memory because they are categorized together. Each day there was a rotation between cleaning the deck, keeping watch, collecting data, or steering and managing the sails. Every day I worked with the same people and devices so that my brain categorizes all the experiences together. Furthermore, because the days all blend together, I must make many inferences when retelling stories from the ship. All the other memories blend together and I would have to infer based on the general episodic memory what a specific memory was.

Under implicit memory (nonverbal memories) are procedural and emotional. Procedural memory is tying the knots and knowing how to haul on a line to raise a sail. These skills are stored by the basal ganglia and the cerebellum. Emotional memory activates the amygdala and the cingulate gyrus. An example of an emotional memory is how scared I felt during the gale when I was absolutely freezing despite my many, many layers of clothing. I also retain an emotional memory that is difficult to pinpoint with a name, but was a result of being completely calm, serene, yet overwhelmed by the power of the massive ocean that extended for hundreds of miles in each direction. I remember feeling elated at being surrounded by nothing other than blue sky and blue water, feeling excited standing at the helm as the only person steering such a huge sailing vessel, and proud walking around the ship knowing the names of the lines and sails.

Sleep is a very important step in the process of learning and memory because when you learn something, the hippocampus holds information that you pay attention to and elaborate on. Then, the hippocampus makes a new firing pattern with the new information. However, this pattern needs to be refired for three nights so that the proper proteins can be synthesized and so that the pattern can be recognized and stored as something you have learned. The physical change that occurs in the brain during rapid eye movement sleep as well as non-rapid eye movement sleep is the growth of new dendrites, which is seen in the neo-cortex and cerebellum in the form of connections between new memories or new networks.

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