MULTI STORE MODEL OF MEMORY

• Sensory memory --> ATTENTION --> Short term memory --> REHEARSAL --> Long term memory (Maintenance rehearsal)
• Baddeley (1996) - coding in STM and LTM

  Gave different lists of words to four groups 
• Baddeley - STM list

  Group 1 – acoustically similar words – cat, cab, can 

  Group 2 – acoustically dissimilar – pit, few, cow 
• Baddeley - LTM

  Group 3 – semantically similar words – great, large 

  Group 4 – semantically dissimilar – good, huge, hot 

  Participants were shown these words and asked to recall them in the correct order 
• Results and conclusion

  STM – worse with acoustically similar words 

  LTM – worse with semantically similar words 

  Conclusion – findings suggest information is coded acoustically in STM and semantically in LTM 
• Evaluation of Baddeley's study

  ✅ Replicable  

  ❌Lacks ecological validity 
• Miller (1956) - digit span studyhought the span of the STM is about 7 items +- 2. People can recall five words as easily as 5 letters through chunking (grouping numbers or letters) 
• Peterson and Peterson (1959) - duration of the STM

  Tested 24 students in eight trials each 

  1. The student was given a consonant syllable (e.g. YCG) to remember 
  2. They were also given a three-digit number to count back from in threes to avoid any mental rehearsal 
  3. Each trial they were told to stop after varying periods of time (3,6,9,12 seconds of time) 
• Findings of Peterson and Petersons study

  After 3 seconds average recall was 80% but after 18 seconds it was about 3% 

  These findings suggest the STM duration may be about 18 seconds unless we do a verbal rehearsal. 
• Evaluation of P+P trigram study

  ✅ Replicable 

  ❌Meaningless stimuli – lacks external validity 
• Bahrick et al - duration of the LTM

  Studied 392 American participants aged between 17-74 

  1. The first test was photo recognition from a yearbook (50 photos) 
  2. The second test was a free recall test where ppts named as many people from their graduating class as possible 
• Bahrick et al - findings 

  Photo recognition:  

  15 years later – 90% accurate 

  48 years later – 70% accurate 

  Free recall: 

  15 years later – 60% accurate 

  48 years later – 30% accurate 

  This shows that the LTM may last up to a lifetime for some material
• Bahrick et al - evaluation

  ✅ High external validity – more meaningful memories 
• Sensory memory


  Encoding - depends on the sense

  Capacity - high capacity

  Duration - less than 1/2 second
• Short term memory


  Encoding - coded acoustically

  Capacity - limited capacity

  Duration - limited duration
• Long term memory


  Encoding - coded semantically

  Capacity - unlimited capacity

  Duration - up to a lifetime
• Strength (1)

  ✅ Research of the MSM shows that the stores operate independently. For example, Baddeley found that we encode acoustically in the STM and semantically in the LTM. However, studies on each store have been conducted in a lab setting therefore lacking ecological validity e.g. the information participants had to remember did not have any relevant meaning. This shows that the findings are not valid.  
• Strength (2)

  ✅ Scientific evidence conducted on the STM and LTM shows that the prefrontal cortex is active in STM tasks, and the hippocampus is active in LTM tasks. 
• Strength (3)

  ✅ Case study (HM) - he had a bike accident and experienced seizures as a result so had to have a lobotomy (removed areas of the brain). He could not create new memories – lost his LTM but not his STM (if they were one unit, he would have lost both). 
• Strength (4)

  ✅ Clive Wearing suffered from a brain infection which damaged his hippocampus and therefore could not remember anything from his LTM. This proves that our STM and LTM operate independently. However, Clive could still play music on the piano, remember his wife and write in his diary. Therefore, this means there must be several types of LTM’s. 
• Limitation (1)

  ❌ Case study (KF) - motorbike accident – could not remember a list acoustically but could visually e.g. grocery list. This shows that the STM is split into various parts (visual/acoustic) - visual memory was good but acoustic memory was poor thus challenging the MSM’s assumptions that the STM is one store. 
• Limitation (2)

  ❌ MSM is too simplistic – maintenance rehearsal cannot be the only way to remember information. Another way to remember information is through elaborative rehearsal, which is where you attach meaning to information.