Sample response

Memory is a complex cognitive process.  It involves the encoding, storage and retrieval of information. As the process is complex, models are used to explain how memory works.  An early model of memory was proposed by Atkinson & Shiffrin, called the Multi-Store model.  This model was the first to distinguish between short-term and long-term memory stores.  A later model is schema theory, which argues that memories are not “stored” as whole memories, but are reconstructed. These two models explain different aspects of memory and have different evidence and limitations.

The Multi-store model explains that all memory is taken in through our senses. This information enters our sensory store, where if we pay attention to it, it will pass to short-term memory. Short-term memory is limited in duration and capacity. According to Miller, STM can hold only 7 plus or minus 2 pieces of information. Short-term memory lasts for six to twelve seconds. When information in the short-term memory is rehearsed, it enters the long-term memory store in a process called “encoding.” When we recall information, it is retrieved from LTM and moved back into STM.

The case study of HM provided biological support for two different memory stores.  HM had a temporal lobectomy to end his epileptic seizures.  The loss of his hippocampus meant that he could retrieve information from before the surgery, but he could not create new memories. He could, however, hold a conversation, showing that he had working (STM) memory.  It appears that the hippocampus is responsible for transferring information from short-term memory to long-term memory. This supports that there is more than one store for memory. 

Biological research has also supported the idea that repetition is necessary for memory.  Repetition leads to long-term potentiation of the synapses, making the connection “stronger.”  Finally, research by Glanzer & Cunitz found that when given a list of words without distraction, people tend to remember the beginning of the list (repetition leads to LTM) and the end of the list (still in STM).

Although this model helped researchers to conceptualize memory, there were some limitations. First, it does not address all different types of memory.  For example, in the HM study it was found that procedural memory was not affected by the removal of the hippocampus.  In addition, emotion appears to play a role in the strength of memories – something called flashbulb memories.  The argument is that repetition may not be necessary for all memories – but instead a powerful emotion, possibly tied to adrenaline and the amygdala, may create memories.  Finally, the model does not address memory distortion.  This is a key difference between the MSM and schema theory.

Schema theory is a model of memory in which we store “mental representations” that come from our prior experience and knowledge.  When we create a memory, we do this in light of our schema.  Schema act as a filter.  As Brewer & Treyens found, when remembering an office, people don’t create a memory of “the office”, but instead rely on their knowledge of offices to form a memory. Participants were asked to wait in an office for 35 seconds for the experiment to begin.  When they were called in, they were asked to recall as many items as they could from the office. The researchers found that they tended to recall items that were in a typical office, even if they were not in the office they had been in (for example, bookshelves).  In addition, they failed to recall items that were not typical of an office (a brick).  In other words, memories are created not just by sensory input as the MSM argues, but through top-down processing in which memories of past similar experiences influence what is remembered and how it is remembered.

According to schema theory, we tend to pay more attention to stimuli that match our schema and not pay attention to stimuli that do not.  This is a significant difference to the MSM in that the MSM does not explain why we pay attention to a stimulus or not. In addition, schema theory argues that memory is reconstructed – that is, when I recall a memory, I am not producing a “snapshot” of the memory, but instead activating different schema.  Remembering a day at school involves schema of people I know, the school building itself, a “script” for how a day at school goes, etc.  Because memory is reconstructed, distortion can occur. I remember a friend being at school today because that is my schema for English class – even though the friend was absent.  This distortion is something that the MSM cannot explain.

Schema theory has a few limitations that are different from the MSM.  Schema theory does not explain where memories are stored.  And although there is an attempt to explain different types of schema, it does not address STM and LTM as different.  Clearly when a schema is “activated”, it comes into STM.  Schema theory as an explanation of memory cannot be well understood without the MSM.  

The MSM explains that if memories are not rehearsed, then the memories are lost or “decay.”  Schema theory does not clearly explain why memories are forgotten.  Finally, as seen above, the MSM has biological support– whereas schema does not have clear biological support.

The two models together give us a good understanding of how memory may work.  Both models have different limitations, but both models fail to address different types of memory and the role emotion plays in the creation of memories.

920 words