Multi-Store Model of Memory

Multi-Store Model of Memory

1. Coding- the form in which information is stored

2. Capacity- how much information can be stored

3. Duration-how long information can be stored for

4. Sensory Register

   • -not under cognitive control -automatic response to sensory info from sense organs 
   • Coding in the SR
     • -info is processed in the way that it's received by the sense organs  -Iconic memory- visual -Echoic memory- auditory information 
     • Crowder
       • -information is only retained in iconic store for milliseconds -echoic- 2/3 seconds -supports idea that we code information in different stores and for different durations of times  visual->auditory
   • Capacity in the SR
     • Sperling- letters on screen
       • -Flashed 3x4 array of letters onto the screen  -different tones high, medium,low to indicate recall of row of letters  -recall was high- supports capacity of SR is large 
     • Evaluation
       • -Calculating capacity of SR involves experiments  -These only provide estimates of capacity  -Lack mundane realism/ ecological validity 
   • Duration of SR
     • -Limited duration  -Each type of store decays at different rates -Some evidence that duration decreases with age 
     • Walsh & Thompson- iconic/age
       • -Iconic store duration of 500 milliseconds  -decreases as individuals get older  -duration of sensory memories is limited and dependent on age 
     • Treisman-echoic
       • -identical auditory information to both ears of ppts -slight delay between presentations  -ppts noticed info was same if delay of 2 secs or less  -echoic store therefore has a duration of 2 secs (differs from iconic store) -echoic store duration is longer 
     • Evaluation
       • -Brief duration of sensory memories due to engrams fading quickly (memory trace) -Suggests a biological basis  -Evolutionary explanation only need to focus on perceptual info with an immediate survival value 

5. Short Term Memory

   • -receives info from the SR -An active changing memory  -Contains info currently being though about  -Receives info from SR via attention under conscious control 
   • Coding in the STM
     • -Arrives from SR and encoded by STM in a form it can more easily deal with  -can encode by:  -visual thinking of an image of food  -Acoustically repeatedly saying food Semantically- using knowledge of food
     • Baddeley- 4 lists acoustic coding
       • -Whether coding in STM and LTM is mainly acoustic or semantic  -ppts presented with 4 lists 4 times  -List A words that sound the same  -List B words that sound different  -List c words that all mean the same  -List D words that have different meaning 
       • -To test STM :  -ppts given list of original words in wrong order  -task is to rearrange words in the correct order 
       • Findings - STM ppts given list A performed worse confusing similar sounding words  Conclusion - STM is coded on acoustic basis 
       • Evaluation  Makes cognitive sense  -Lab study so shows causality so can be replicated  -lack ecological validity 
   • Capacity
     • -Limited capacity  -5-9 items  -capacity can be increasednby chunking 
     • Jacobs-digit span method
       • -ppts presented with increasingly long lists of letters or numbers  -numbers tend to be recalled better than letters  -lacks ecological validity 
     • Evaluation
       • -other factors like age and practice can influence STM capacity  -Processing limitations due to attention 
       • Daneman + carpenter  STM capacity varied between 5-20 items between those with advanced and poor reading comprehension  -Individual differences therefore in STM capacity 
   • Duration
     • Limited to 18-30 seconds  -can be extended through rehearsal  -rehearsal transfers info into LTM 
     • Peterson +Peterson-nonsense trigrams
       • ppts punted backward in 3's to prevent rehearsal for different lengths of time  -90% recalled correctly after 3 secs -5% recalled correctly after 18 secs  -Suggests STM duration between 20-30 secs
       • Evaluation  -different trigrams on each trial interference leading to decreased recall  -nonsense trigrams lacks ecological validity 
     • Evaluation
       • Reitman brief duration of STM due to displacement  Little research evidence considering the STM duration of other forms of stimuli e.g visual images 

6. Long Term Memory

   • Stores info for long periods of time  -different types of LTM  -LTM may change over time/merge with other LTMs -process of shaping and storing LTMs spread through multiple regions in the brain 
   • Coding in LTM
     • the form by which LTMs are stored deeper processing leads to better recall  -coding in LTM is mainly semantic 
     • Baddeley
       • LTM ppts given list C performed worst  confused similar meaning words  -LTM is coded on a semantic basis 
     • Nelson and Rothbart-acoustic
       • Showed acoustic coding also in LTM  ppts made errors recalling homophones e.g night and knight  -suggests coding in LTM has several varieties 
     • Evaluation
       • There must be several forms of encoding in LTM  -songs are coded acoustically  -smells and tastes semantically coded  -varying forms of coding in LTM involve different brain areas 
   • Capacity of LTM
     • unlimited capacity  info may be lost due to decay or interference 
     • Wagenaar-Diary
       • Diary of 2,400 events over 6 years -tested himself on events (not dates) -excellent recall  -case study so not representative of population  -element of bias 
     • Evaluation
       • LTM assumed to be limitless - no research determining finite capacity  -Evolutionary basis to LTM animal studies  -Enlarged memory capacity has a survival value 
   • Duration of LTM
     • -Depends on individuals lifespan -LTM have a longer duration if well coded  -Better if based on skills rather than facts  -info doesn't have to be rehearsed for it to be retained e.g flashbulb memories 
     • Bahrick- photos of friends
       • -ppts showed photos and names  -some were ex school friends  -left in last 15 years - 90% faces/names recalled correctly  -Left 48 years ago -70% names and faces  -memory for faces is long lasting 
     • Evaluation
       • Lost info in LTM more of an issue with access rather than it not being there  -type of testing -ppts better at recognising stimuli than recalling 

7. MSM evaluation

   • Strengths
     • First explanation and influential in inspiring research/other models
     • Considerable research evidence for separate memory stores
     • Model supposed by amnesia cases e.g HM, Clive Wearing
     • Serial position effect primacy and recency effect separate LTM and STM stores
   • Limitations
     • Oversimplified
     • Assumes single STM and LTM stores
     • Criticised by WMM
     • Types of LTM
     • Describes memory in terms of structure not enough focus on the processes involved in the stores