Understanding memory still has a far way to go, many theories and studies have been investigated on how memories are stored in the brain. Storing and retrieving memories is described as a process. Many models have been suggested on how the memories are organized.
As background, working memory occurs within a cycle. Memories begin by being encoded, then stored then finally retrieved. Encoding is the processing of information into the memory system, for example, by extracting meaning. The new information is then moved into storage. Storage is the information being placed in long term storage. Memories are also stored with a semantic process. This means that a memory is stored according to what other experiences and what the experience means to the specific person. This system is very personal as everyone experiences different things and believes different opinions. Lastly there is retrieval, which is the process of getting information out of memory storage. Retrieval from short term memory is that chunks of information are recorded in the way they were presented, like a pattern. Whereas retrieval from long term memory is more by relating information you are processing to a previous memory in long term memory.
One main theory is the multi store model, by Atkinson and Shiffrin (1968). They suggested that memory was made up of three parts: sensory memory, short term memory and long term memory. If the memory is repeated then it enters into the long term memory storage. If the memory is not repeated it is forgotten or lost to decay or displacement. The strengths of this model is that it is a reductionist approach which makes it very easy to follow and allows it to be built upon. The theory is significant and has inspired lots of research on the storage of memory. However the reductionist approach also means the model could be over simplified. The process of short term memory to long term memory might be too broad, the transfer or memory could be due to more than just repetition. Research has already shown that there are many different types of long term memory, such as episodic memory.
Murdock’s study from 1962 looked into the serial position effect and how depending on where the word is on a list, the better the word will be recalled later. Murdock had participants listen to a list of words and then recall as many as possible in 90 seconds. The results showed that words at the beginning of the list and the end of the lists were those that were more likely to be remembered. These results show the idea of limited storage and duration, short term memory can only hold so much, so the middle words for example are displaced. More so, the first few words have been repeated to try and memorise the list and they have therefore made it into long term storage. This model gives no explanation to how memories are broken into these subunits within long term memory. This theory gives a baseline for memory.
Working memory theory is another model on the process of memory storage. By Baddley and Hitch (1974) built off of the Multi store model but with more focus on short term memory. Working memory is a term for cognitive process happening in the present, right now. They suggested that short-term memory is not a static store, but a complex and active information processor, made up of several dynamic subsystems. The working memory does not cover the whole process but only adds more detail to short term memory. They suggested that short term memory acts as a central processing unit, broken down into three categories to be able to function. The central executive, the phonological loop and the visuospatial sketchpad. The central executive has the most important role. It has a role responsible of overseeing the visuospatial sketchpad, phonological loop, and episodic buffer. It is also responsible for shifting and dividing attention. The phonological loop is the part that holds verbal and written material. Numbers and words can be repeated in the loop until stored or transferred. The Visuospatial sketchpad holds visual information and spatial awareness. This process happens inside of the multi store model. The information enters short term memory as usual but must go through these different parts before heading to long term memory. In 2000, Baddeley added in a missing piece between short term memory and long term memory, an episodic buffer. The episodic buffer holds information and allows it to be passed backwards and forwards between working memory and long term memory. Although the theory is better, it is not perfect. The first criticism is that this theory is not complete as it has a focus on only short term memory.
The working memory model makes several improvements from the multi store. It is much more realistic and detailed. The short term memory’s capacity now is not static and changes according to different variables. The working memory model also allows for multiple processes in short term memory at once, which is realistic as most people are dealing with multiple inputs, almost all the time. However emotions and biological impacts have an effect on the storage of memory which are not covered in either model. Neither model is detailed enough to be the foolproof explanation of memories in the human brain.