Multi-store model of memory

Who designed the multi-store model of memory?

Richard Atkinson & Richard Shiffrin

Define the multi-store model of memory

• A representation of how memory works in terms of sensory register, short-term memory & long-term memory. Describes how information is transferred from one store to another, what makes some memory last & disappear

Describe the first stage

• All stimuli from environment e.g someone talking, pass into sensory register - comprises several registers, one for each of 5 senses

• Coding is modality specific (depends on sense) - e.g store coding visual info is iconic memory & store coding auditory info is echoic memory

• Duration 0.05 seconds for iconic memory but about 3 seconds for echoic memory

• Very high capacity

• Information passes further into memory system only if you pay attention

Describe the second stage

• Short term memory lasts about 18 seconds unless rehearsed

• Coded acoustically

• Temporary & limited capacity - about 5-9 items

• Maintenance rehearsal occurs when we repeat information to ourselves repeatedly until enters LTM

Describe the third stage

• LTM potentially lasts up to a lifetime & potentially unlimited capacity - info coded mostly semantically

• When we want to recall info from LTM, it has to be transferred back into STM through retrieval.

Evaluation - separate stores & counterpoint

• Larry Squire reviewing neuroimaging studies that compared brain areas associated with STM & LTM

• Prefrontal cortex significantly active during tasks involving STM whereas hippocampus (+ other structures) have been associated with reorganisation & consolidation (LTM)

• Regional differences suggest LTM & STM are independent & separate stores

→ Counterpoint: others argue this view is oversimplified & there is significant overlap & interaction between brain regions that support STM & LTM e.g hippocampus also involved in STM tasks, particularly when task involves complex & new info. This suggests that evidence for a clear-cut separation is not strong

Evaluation - more than one STM store

• Tim shallace & Elizabeth Warrington studied KF who developed amnesia after a motorcycle accident

• KF’s STM for digits was weak when read aloud to him, but his recall was much better when reading digits himself

• Further studies indicate there could be another STM store for non-verbal sounds

• This suggests that MSM is wrong in claiming there is just one STM store processing different types of information

Evaluation - elaborative rehearsal

• Fergus Craik & Michael Watkins found that type of rehearsal is more important than amount

• Elaborative rehearsal is needed for long-term storage - occurs when you link information to existing knowledge, meaning info can be transferred to LTM without maintenance rehearsal

• This suggests that MSM does not fully explain how LTM storage is achieved

Evaluate - clinical evidence + Counterpoint

• Support from Tim Shallice & Elizabeth Warrington’s (1970) case study of a petting KF who after his brain injury, had poor STM ability for acoustic info but could process visual information just as well before injury

• KF’s phonological loop was damaged but his visuospatial sketchpad was intact. This finding strongly supports the existence of separate subsystems for visual & acoustic information

→ Counterpoint: Unclear whether KF had other cognitive issues which may have affected his performance on memory tasks

E.g his injury was caused by a motorcycle accident. Trauma may have affected cognitive performance quite apart from any brain injury

Evaluate - Neuroimaging evidence

• Evidence from brain scans for existence of subsystems in working memory

• Edward Smith & John Jonides (1997) used PET to show that tasks using the phonological loop were linked to activation in left temporal & frontal lobes, while tails using visuospatial sketchpad were associated with activity in right parietal lobe, providing reliable & objective for working memory’s subsystems

Evaluate - nature of central executive

• One limitation is that there is a lack of clarity over the nature of the central executive

• Baddeley (2003) said ‘the central executive is the most important but the least understood component of working memory

• The central executive needs to be more clearly specified than just being simply ‘attention’ → e.g some psychologists believe the central executive may consist of separate subcomponents

• This means that the CE is an unsatisfactory component & this challenges the integrity of the working memory model.