multi store model

Atkinson & Shiffrin (1968) multi store model

describes how information flows through the memory system, suggests memory is made up of 3 stores

sensory register

• all stimuli from the environment pass into the sensory register, we have 5 stores, one for each sense

• duration: stays for a very brief period, 1/2 a second, before decaying or passing on to the STM store

• coding: modality specific, depends on the sense

• capacity: very high

• we use mainly our iconic memory for visual information and our echoic memory for auditory information

• little information from SR passes into memory

how is information passed from sensory register to STM?

information passes further into memory only if attention is paid

short term memory

• capacity: thought to be 7+/- 2 items

• duration: very small duration up to 30 seconds, can be lost within a few seconds if not rehearsed, items usually held in the STM store as sounds, most information lost before 18 seconds

• coding: mainly visual and acoustic

• if information is rehearsed (maintenance rehearsal) it is passed onto the LTM

• we can often hold larger amounts of information by chunking where the information is consolidated into chunks

how is information passed from STM to LTM?

maintenance rehearsal occurs when we repeat (rehearse) material to ourselves, we can keep information in STM as long as we rehearse it, if its rehearsed enough it passes to LTM

long term memory

• has a potentially limitless capacity and duration, difficult to prove

• coding: semantic, the meaning and understanding

• 3 types of LTM:

• episodic: memory of events

• semantic: general knowledge

• procedural: knowing how to do things

• when we want to recall information from the LTM, it has to be transferred back to the STM by retrieval

primary-recency effect

• well known experiment demonstrating the MSM, participants are read a list of words then have to recall them either immediately or after a distraction

• recall of 1st and last words are best, recall for middle is poor

• in immediate recall the first words are in the LTM as they have been rehearsed and transferred, last words are still being rehearsed in the STM, words in the middle are less well recalled as you were too busy rehearsing the 1st to remember them well

case study of KF- Shallice & Warrington 1970

• MSM states STM is a unitary store i.e. only one type of STM

• people suffering from amnesia shows this can't be true, KF had problems with information presented to him verbally (acoustic), his recall was much better when he could read them himself (visual)

strength of MSM- support showing STM and LTM are different

• Baddeley (1966) found we tend to mix up words that sound similar when using our STM's so STM coding is acoustic

• but we mix up words that have similar meanings when we use our LTM's so LTM coding is semantic

• supports the MSM's view that these 2 memory stores are separate and independent

support showing STM and LTM are different counterpoint

• despite such apparent support, the studies tend not to use everyday information eg faces, names, they use digits/ letters (Jacobs) or meaningless consonant syllables (Peterson & Peterson)

• therefore MSM may not be a valid model of how memory works in everyday life where memory tends to involve meaningful information

limitation of MSM- evidence suggesting there is more than one STM store

• KF had amnesia (Shallice and Warrington 1970), STM recall for digits was poor when he heard them, but much better when he read them

• other studies confirm there may also be a separate STM store for non verbal sounds eg noises

• therefore the MSM is wrong to claim there is just one STM store processing different types of information

limitation of MSM- prolonged rehearsal isn't needed for STM to LTM transfer

• Craik & Watkins (1973) argued there are 2 types of rehearsal, maintenance and elaborative, maintenance (amount of rehearsal) is the one described in the MSM

• but elaborative rehearsal is needed for long term storage, occurs eg when you link information to existing knowledge or think about its meaning

• suggests the MSM doesn't fully explain how long term storage is achieved

evaluation of MSM- bygone model

• MSM was a useful model that explained a lot of evidence at the time eg differences between STM and LTM

• however it has become clear that it can't account for many research findings eg amnesia and oversimplifies the nature of STM, LTM and rehearsal

• therefore, MSM was a good starting point for developing more valid models of memory that explain the research evidence better