The Readings for the Week of Jan 29th

The main focus of this week’s readings are models of memory. Memory models have been constructed to explain how things like phone numbers, facts, and important events become stored in our long-term memory. There are several models but most of them follow a similar blue print called the Modal Model of memory. In this model, information received from the environment goes through several processing steps before it has the possibility of being stored in one’s long-term memory. Richard Atkinson and Richard Shiffrin developed the Dual Store Model, which follows the modal model blueprint. The first stop for an external stimulus is the sensory register, which is based on the nature of the information. For example if the stimulus is visual, it enters a visual sensory register. One question I had about this stage was what happens when a stimulus has both auditory and visual properties? Is the information processed simultaneously or separately?

The second stop is short-term store (STS) which has a limited capacity. The short-term memory storage’s capacity explains why information is lost and why information stays here for only a short period. It is during this stage that the information from the stimulus is further analyzed and processed. For example, if one sees the word dog, the word’s case, its letters, how it is said, and its meaning are all processed. One may also associate this word with life experiences to strengthen its meaning. This stage is crucial because the longer the information stays in STS the more likely it is to be stored in the long-term memory store. Rehearsal also increases the likelihood that information will be stored. Without the short-term memory store, the information we get from external stimuli can never become concrete and be stored in our long-term memory.

Reading about this second memory stage made me to think about patients with amnesia. We read last week that anterograde amnesia is when a person cannot form new memories because they are unable to transfer events from their short-term to their long-term memories. This is commonly seen in people with brain damage and in soap operas. This type of amnesia can be either temporary or permanent. The second type of amnesia, anterograde amnesia, is the inability to form new memories. Anterograde amnesia is commonly seen as a permanent condition and not a temporary one. This led me to ask the following question: Does temporary anterograde amnesia exist? After doing some research on Wikipedia, I found an entry that discussed the types of anterograde amnesia. It was here that I found about the term traveler’s amnesia which is the name given to temporary anterograde amnesia. Traveler’s amnesia can be caused by the intake of certain medications (Benzodiazepines and imidazopyridines) and the consumption of a large amount of alcohol. Wikipedia also introduced me to a second type of temporary anterograde amnesia called amnesia automatis. Amnesia automatis is caused by the consumption of alcohol and prescription drugs simultaneously. Those who suffer from this type of amnesia suffer memory blackout and do very strange things that they later do not remember doing. These strange actions are done automatically by amnesiac without any thought, which is why sometimes they do not know how they did these things.

The last and final stage of memory/information processing is long-term storage (LTS). The capacity of this storage is infinite and it is here where information like our childhood memories and factual knowledge is stored. The memories stored here have already been processed thoroughly and are not usually forgotten. One exception to the permanency of the memories in this storage is if one suffers from retrograde amnesia.

This week’s reading also discusses the serial position curve, which is based on data collected from free recall tasks. During this task, people see a list of letters or numbers and are asked to recall them afterwards. The plot of this data revealed that people remember the items presented first and last better than the items in the middle of the list. The terms used to explain this trend are the primacy and recency effect. The primacy effect is when a person remembers the first few items of a list and the recency effect is the opposite. It is when a person remembers the last items presented on a list.

This curve, the recency effect, and the primacy effect have been introduced in almost every psychology course I have taken. During these classes, I just accepted the fact that the recency and primacy effect exist without testing it myself. This is what led me to search for internet memory experiments that administered free recall tasks and analyzed the information from this task. After some extensive googling, I finally found a website that lets you take the experiment. The first time I did this experiment, I recalled the items in the middle of the list the best. I do not know what this means, but it disproves the recency and primacy effect. My serial position curve also looked nothing like the one in the textbook. It was shaped more like a bell curve. Factors that I thought could have affected my results could be the way the experiment itself was made or my own bias.

If you want to take the memory experiment go this website:
http://www.essex.ac.uk/psychology/experiments/memtask.html