Outline and evaluate the multi store model of memory.

by raj-kaur (student)

Raj

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Outline and Evaluate the Multi-Store Model

The idea of a multi-store memory, was discovered by Atkinson and Shiffrin in 1968, and argues that memory can be divided into three separate structures; Sensory memory, Short-term memory and Long-term memory. Information is thought to enter the memory system through the Sensory memory, and then passed on to the Short Term memory when attention is paid to it. If this information is thought about and rehearsed in the Short Term memory it is passed to the Long-Term Memory to help interpret information in Short Term Memory. The Sensory Memory, which is uses visual, auditory and tactile encoding, has a limited capacity however, and a brief duration, so for information to be useful, it has to be passed on to Short Term memory. The Short Term Memory uses mainly acoustic encoding, has a limited capacity and also, a brief duration, so for us to recall information for longer durations, it must be rehearsed and passed to the Long Term Memory. The Long Term Memory has a mainly semantic coding, an unlimited capacity, and an unlimited duration.

There is much evidence to support the multi-store memory model. Clive Wearing, suffered a herpes virus which spread to his brain, destroying his hippocampus in particular as well as areas of his cortex. This meant he could not transfer information from his short term memory to long term memory. He has also lost large amounts of his episodic long term memory, so he finds it difficult to remember specific events. Although, he has all his motor skills and some factual knowledge from before his illness, he has little else. This case study is so important as it suggests that there must be separate Short term and long term memory stores since there clearly has to be some transfer mechanism between the two. It also suggests that the transfer process is located in the hippocampus. However, although this case study supports the Multi-model store idea, and has much mundane realism, it is dangerous to generalise from one study to be others, and because this is a retrospective study, researchers tend to only notice information which fits their theories.

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More evidence to support the multi-store model can be seen by the serial position curve experiment, by Glanzer and Cunitz. The experiment produces the primary effect, where many words are recalled from the beginning of the list, and the recency effect, where many words are also recalled from the end of the list, but not so many from the middle. This study also shows that there are separate short term and long term memory stores since the primary effect occurs because the words at the beginning of the list have been rehearsed, and so are transferred into the long term memory store. However, whilst this is going on, less attention is paid to the middle words and they tend to be lost unless they have some special significance to the individual. The words at the end of the list are well recalled because they are still fresh in the memory system unless there is a distractor task which causes this information to be lost through interference, displacement, or decay. This evidence can be seen as reliable since it was scientific, conducted in a laboratory, and produced quantative data that makes it easy to summarise and compare with other data. However, it can be argued that this experiment lacks mundane realism and does not reflect real life memory tasks, also that it doesn’t take into account people’s varying ways of remembering words, which may bias the results. Furthermore, individual differences, such as people’s attention spans were not taken into account, which could also bias the results, and there is no evidence the primary effect reflects the long term memory, and it could be due to the words used.

Furthermore, another case study to support the multi-store memory model is the case of H.M. H.M. had suffered epileptic fits of devastating frequency from the age of 16, and as a last resort, underwent surgery, at the age of 27. The surgery involved the removal of tissure involved in the fits. This included the anterior two thirds of his hippocampus and amygdale, and parts of termpoal love on both sides of his brain. The surgery improved his epilepsy, but caused severe memory problems. H.M. could remember everything before the surgery and his short term memory worked well, but like Clive Wearing, he was unable to transfer information from his Short Term memory, to Long Term memory. It seems impossible for him to store any new semantic or episodic information. Although this could seem unreliable and dangerous to generalise, since it was a case study, this appears to be firm evidence to support the Multi-store Memory model.

However, there is much evidence to contradict Atkinson and Shiffrin’s theory. A case study of that of K.F. is one example of this. K.F. sustained brain injuries after a motorbike accident. His long term memory remained intact and he was unable to learn new information, however his short term memory capacity was much reduced. In fact his recency recall was of only 1 item, which suggests there are other parts to the memory apart from that of the Short term memory stores and long term memory stores. However, the reliability of this study can also be brought into question since it is a case study, so has all the problems which occur with a case study, as stated above.

Baddeley’s working memory model, also strongly contradicts the multi-store memory. The Working Memory model re-formulates the structure of the Short Term memory and argues that its purpose is not to store information and pass it to the Long Term memory, but instead it is the source of our conscious thinking processes. It is a system that allows us to manipulate information, not just store it before passing it on. It is, instead the site of our thinking processes. Rather than being a unitary store, it is made up of a number of subsidiary systems. Research supporting the working memory model can be seen in Baddeley, Thomson and Buchanan’s research in 1975 of the phonological loop. Their research saw participants recalling one word at a time, of varying lengths. They found that performance was superior in short words (monosyllabic), rather than polysyllabic words. This shows that the capacity of the phonological loop is determined by the length of time it takes to say the words to yourself rather than the number of items. So there are some confounding variables that can alter your ability to remember some words, rather than just rehearsal, or attention, as suggested in the multi-store memory model. Of course, this experiment lacks mundane realism, but tested many Participants, and produced quantative data, in controlled laboratory conditions, such can be considered to be reliable.

Other criticisms of the Multi-memory store memory model suggests that it places too much emphasis on rehearsal, and attention to the information which is to be passed on through the memory stores, and that actually there are other variables to be considered, such as the length of the words, or the sounds of the words. From the case studies I have quoted, contradictory to the multi-store model, there must be other ways of transferring information from the short term, to the long term memory stores, or these case studies wouldn’t be possible.