Multistore model of memory. Working memory model.

The Atkinson-Shiffrin multistore model is a model of memory proposed in 1968 by Richard Atkinson and Richard Shiffrin. This model of memory has three separate components:

Sensory stores (register)

Short term store

Long term store

Each store is a unitary structure and has its own characteristics in terms of:

Encoding – is the way information is changed so that it can be stored in the memory. There are three main ways in which information can be encoded (changed):

Visual – picture

Acoustic – sound

Semantic – meaning

Capacity concerns how much information can be stored.

Duration refers to the period of time information can last in the memory stores.

Information first enters the sensory store – sensory memory, directly from the senses. It remains the sensory store for a maximum duration about 2 seconds before is replaced with the new information. If information in the sensory store is attended to then it can be passed to the short memory store.

Information passes from the store to the store in a linear way, and has been described an information processing model with input, process and output – like computer.

Information from the short-term memory is transferred to the long-term memory only if that information is rehearsed (i.e. repeated). When information enters the long – term store it remains there for even the life time. The capacity of the store is potentially unlimited and encoded information is stored by its meaning.

If maintenance rehearsal does not occur, then information is forgotten, and lost from short term memory through the processes of displacement or decay.

The experiment that supports this model is Sperling (1960) which aim was to find out the existence of sensory memory. The participants were asked to look at the chart in which is written 12 letters.  They were asked to look at it for 50 milliseconds and then were asked to recall how many of the letters do they remember. Then Sperling got the participants to recall single rows of letters when particular tones were heard. High tone for top row, medium tone for middle row and low tone for the bottom row.

Another experiment that supports this model is Glanzer and Cunitz (1966) and the aim of the experiment was to test the hypothesis the short – term memory and long – term memory are two separate stores. The researchers presented 240 army enlisted participants a list of 15 words which the participants knew they had to memorize. Half of the participants were instructed to recall the list straight after presentation for the immediate recall condition. The other half were asked to recall after 30 seconds (the delay free recall). The results showed that the first half of participants recalled more words at beginning and the end of the list. Glanzer and Cunitz found that a delay of 30 seconds does not affect recall from the long-term store thus the primary effect was affected by the delay in the second half of the participants. Glanzer and Cunitz showed that when participants are presented with a list of words, they tend to remember the first few and last few words and are more likely to forget those in the middle of the list, i.e. the serial position effect.

This supports the existence of separate LTM and STM stores because they observed a primacy and recency effect.

The study of HM supports the model because it shows that the long term and short – term memories are two different stores. After having his hippocampus removed due to surgery for epilepsy, his short – term memory remained intact. However, after the accident, HM’s long – term memory had been damaged as he was unable to form new memories. He couldn’t transfer new information into his long – term memory. Despite being able to remember people he had known long ago, new people he had encountered were like strangers to him. There are specific deficits in which some abilities, such as learning new information are impaired whilst others like language are quite normal. One strength of the multistore model is the it gives us a good understanding of the process of short-term memory and allows researchers to expand this model. This means that they can do experiments to improve this model. This is also gives us more understanding about long-term memory as studies provide evidence to support the distinction between STM and LTM.

Evidence against the model is the idea of flashbulb (super-fast) memories. It contradicts the multistore model as the information appears in the long – term store without being rehearsed. Actually, this is true, in everyday life we almost never rehearse information so this cause a problem for storing huge amounts of information. So, this idea criticizes the whole idea of rehearsal. There are some important things happened in their life time that individuals will remember without rehearsing this kind of information and it will stay for really long time maybe even all life time. So, the model is oversimplified the short-term and long-term memory does not operate by their own single way. In case of long-term memory, it is unlikely that different kinds of knowledge, such as remembering how to play hide and seek rules and how to walk all stored in one single, long-term memory store. Rehearsal is considered a too simple explanation to account for the transfer of information from STM to LTM. 

The study of KF also criticizes the model because KFs visual short-term memory remained undamaged after brain damage due to a motorbike accident and KF could also store long term memories without them needing to pass through his damaged long – term memory. This criticizes the model in two ways: according to the multi store model, memories have to pass through the short – term memory in order to be stored in the long – term memory. KF’s verbal short term memory was damaged despite his visual memory being intact, suggesting that the short – term memory isn’t a unitary store, with different parts dedicated to processing different types of information.

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