MEMORY: multi store model of memory

AO1

Atkinson and Shiffrin 1968 came up with he multistage model of memory (MSM). It consists of 3 memory stores , the sensory register, short term memory and long term memory

sensory register

where information is held at each of the 5 sneses. The capacities of these are very large however most of the information is lost as it receives no attention. The duration is very limited (milliseconds)

STM info

info held here for immediate tasks. STM has a limited duration of approximately 18 seconds, and a capacity of 7+-2.

LTM has potentially unlimited capacity and duration

the model diagram

Attention, maintenance rehearsal and retrieval

the three memory stores are linked to each other by different processes that enable the transfer of information from one store to the next.

if a persons attention is focused on one of the sensory stores, then the information is transferred to STM

Rehersal (repetition) keeps information in STM, but eventually reversal will create a LTM. According to Atkinson and Shiffrin, the more information is rehearsed, the better it is remembered.

Finally, information that is stored in the LTM can be returned to the STM by the process of retrieval for use

Strength of MSM - Baddeley supporting evidence

Supporting laboratory evidence for example Baddeley coding research that found LTM codes semantically and STM codes acoustically and that STM and LTM are indeed unitary stores.

Baddeley found that short term memories are usually encoded acoustically, this means that they are processed and recalled through sound before it enters the long term store through reversal. He also found that LT memories are usually encoded semantically, this means that they are transferred into the store through a meaning. The findings by baddeley suggest that as they are encoded and stored very differently thus providing some evidence for the idea that the STM and LT are separate.

For example, Miller 1956 found that the duration of STM is 7+-2 and Bahrick et al 1975 found that the duration of LTM is approximately 48 years.

This supports the idea of separate short and long term memory stores, which is the basis of the MSM

Additional support for the STM and LTM unitary stores comes from recent brain scans that indicate the prefrontal Cortex is active during STM and the Hippocampus for the LTM (Beardsley) suggesting that there is a linear way.

Another strength of the MSM - Scoville and Milner

There are supporting case studies - Scoville and Milner is support for the MSM for having different stores of memory STM and LTM which supports the separation.

Scoville and Milner claim that LTM and STM are in different stores of the brain. They reported the case of HM as he suffered from brain damage from an operation to remove his hippocampus from both sides of his Brian to reduce his severe epilepsy.

Hm’s personality and intellect remained intact but he could not form new LTMs although he could remember things from before the surgery.

This provides support for the MSM as HM was unable to transfer information from his STM to. LTM, but was able to retrieve information from before his surgery, supporting the different processes involved in the MSM.

However… there are problems with using case studies of Brian damaged patines to support the MSM as we do not know what HM’s Brian was like before the surgery , no memory tests were conducted before the surgery and the initial memory loss was largely reported by his mother, with whom he lived which lacks reliability. Furthermore, the high doses of anti-elepitc drug he was taking before, and the lower doses after the surgery, may have resulted in some memory loss. Therefore it is hard to generalise form this unique case to the general population

criticism of the MSM

For it being overly simplistic

the MSM suggests that both the STM and LTM are single, ‘unitary’ stores. However, research doesn't support this idea. research has also found different types of LTM, for example episodic, procedural and semantic memory (WMM).

HM for example had no problem with the concept of a dog being explained to him (semantic) but couldn’t remember stroking one just an hour after he had been asked (episodic). In addition to this, despite being able to from new memories he was able to practice a procedural memory skill of drawing between two stars and improve with each attempt, showing here was a retention of some memory which was implicit or unconscious.

this suggests that the MSM provides a simplistic model of memory and does not take into account the different type of STM and LTM

in addition, a further challenge to the MSM comes from lab studies into short term memory and how it is not a unitary store as once previously though. The WMM by baddeley and hitch suggests that STM is divided into a number of different stores - central executive, phonological loop and the visual spatial sketchpad and later the episodic buffer. Case studies into damaged Brians such as KF indicate that their visual STM perfoms better than their phonological short term memory, indicating that there are further separations and challenge the model proposed by Atkinson and Shiffrin.

6 mark on AO1 starter

Atkinson and Shiffrins Multi-store model of memory outlines that human memory consists of 3 distinct stores; sensory memory, STM, LTM. According to the model, information passes from one store to another in a linear manner: sensory input is briefly held in sensory memory, then transferred to the STM and finally to the LTM through rehearsal

Sensory memory has a very short duration - milliseconds and vert large capacity. STM has a capacity of approximately 5-9 items (miller) - contested to be as short as 4 (Cowen) and an approximate duration of 18 seconds (Peterson and Peterson). LTM with a large duration and unlimited capacity as proposed by Bahrick.

Case of KF

suffered brain damage due to a motorbike accident

experienced memory impairment but in a very specific way

poor STM for verbal info - struggled to remember spoken digits and verbal material

however, intact STM for visual and non verbal information - he could remember images or written digits much better

suggesting different stores within the STM and different effected.

supports Baddeley and hitchs WMM, which proposes separate components

• phonological loop - verbal information- damaged in KF

• Visio-spatial sketchpad - visual info - intact in KF