Multi-Store Model of Memory

• Sensory Register


  capacity = high

  duration = 250ms - 4s

  encoding = iconic, echoic

  (disregarded info is removed before reaching STM)

  (by paying attention info moves into the STM)
• STM


  capacity = 7+-2

  duration = <30s

  encoding = acoustic

  (memory can be forgotten through decay or displacement)

  (prolonged elaborative rehearsal changes STM to LTM)
• LTM


  capacity = unlimited

  duration = potential lifetime

  encoding = mainly semantic

  (retrieval changes back to STM)

  (maintenance rehearsal changes back to STM)
• Strength - research support for existence of structurally separate stores

  Glanzer and Cunitz

  showed recency effect is disrupted when an interference task is introduced

  found the last 2-3 items on a word list were lost from STM but earlier items were remembered as they were already in LTM

  therefore support MSM as it shows the STM and LTM are separate, also showed the importance of rehearsal
• Strength - further support by case studies

  H.M. (Milner et al)

  STM - intact

  LTM - affected

  - justifies the MSM as STM isn't affected but LTM has been affected -> separate

  suffered intractable epilepsy -> medical temporal lobe surgery

  Clive Wearing

  7s memory

  STM - damaged

  LTM - affected significantly

  - justifies the MSM as LTM is completely gone due to 7s memory but STM is still somewhat intact -> never could learn anything new.

  no STM = no rehearsal so no LTM (linear)
• Weakness - contradiction of MSM

  KF

  STM - bad (verbal, worst, visual but too bad)

  LTM - intact

  his LTM worked even though STM was damaged and model says this shouldn't be possible
• Weakness - overly simplistic

  MSM is based on research that suggests STM and LTM are unitary stores that work separately and independently of each other.

  however, there's a lots of research (e.g. Tulving) to suggest that there are different types of LTM.

  e.g. there are separate LTMs for events, facts and skills like riding a bike

  suggests that LTM isn't a single unitary store and there are at least 3 different types of LTM, limiting the validity of the model at explaining the complexity of human memory
• Weakness - not all research evidence supports the idea STM and LTM operate independently

  Shallice and Warrington reported the case study of KF who suffered brain damage which led to difficulty in dealing with verbal info but who could still process visual info normally.

  Schachter et la suggests that evidence from amnesiacs suggests there are 4 different LTMs rather than just one.

  suggests the MSM may be too simplistic and inflexible to explain the entire memory system