The Multi-store Model

• How does memory enter the sensory register? Sensory stimuli.
• How does memory enter the short term memory?

  attention
• How do we retain information in our STM?

  Rehearsal
• How does information enter the LTM?

  encoding
• How do we retrieve information from our LTM?

  rehearsal
• How do we lose information from our SR?


  non-attention
• How do we lose information from our STM?

  not rehearsed by maintenance rehearsal (repetition)

  displacement - shunted out to make room for new information
• How do we lose information from the LTM?

  some lost over time - decays from LTM
• capacity of SR: all sensory experience (very large capacity)
• Duration of SR: 1/4 to 1/2 a second
• Coding of SR?


  sense specific e.g. different stores for each sense
• capacity of STM?


  5-9 items - Miller

  7 +/- 2
• Duration of STM?


  18-30 seconds

  Peterson and Peterson
• Coding of STM?


  Acoustic

  Baddeley
• Capacity of LTM?


  potentially unlimited

  Bahrick
• Duration of LTM?


  a potential lifetime

  Bahrick
• Coding of LTM?


  Semantic

  Baddeley
• Coding in the SR is through senses:

  1. visual - eyes
  2. auditory - ears
  3. haptic - touch
  4. olfactory - small
  5. gustatory - taste
• How long does sensory memory last?


  Sperling - used tachistoscope to present an array of 12 letters and asked PPs to write them down
• Sperling's results:

  when shown all letters - 5 items recalled - about 42%

  when shown one row - all 3 items recalled - about 75%
• Primacy?

  words from the beginning of a list have more rehearsal and therefore transfer to LTM meaning we are more likely to recall them
• Recency?


  words from the end of a list are still in the short term memory so are more likely to be recalled
• Original graph of probability of recall?

  Glanzer and Cunitz
• Terry?


  graph of delayed recall
• strength: Terry's research into Serial Position Effect shows the effects of decay and displacement, highlighting the existence of more than one memory store
• The model is oversimplistic - reductionist:

  There is evidence for different types of LTM e.g. Tulving states that there is semantic and episodic LTM

  Baddeley and Hitch state that there are different types of STM

  Ignores the interaction between the STM and LTM e.g. chunking requires meaning from the LTM

  Over emphasis on rehearsal - elaborate rehearsal can improve recall better than maintenance rehearsal
• Tulving says that there could be more than one type of LTM
• Over emphasises rehearsal - not everything has to be rehearsed to go into the LTM
• Evidence from case studies like Clive Wearing - has LTM but no STM due to a virus that attacked his brain - evidence for the different stores:

  had encephalitis and lost ability to lay down short term memories but still remembers wife and can play piano - procedural memory intact

  evidence for different stores in the memory
• Evidence from case studies against - KF

  Shallice and Warrington

  KF suffered brain damage following a motorbike accident

  digit span was one

  his visual memory was intact

  had difficulty dealing with verbal info in STM but had normal ability to process visual information

  does not support model - some parts of STM damaged - suggests different parts of STM - not just one store
• Can be tested scientifically in lab experiements
• Real life vs rehearsal?


  don't always spend time rehearsing info yet info still transferred from STM to LTM

  some items cannot be rehearsed e.g. smells/ tastes
• Methodological issues?


  issues with methods of testing

  low ecological validity - done in labs - behaviour changes - show demand characteristics

  low construct validity - don't behave normally when in a lab - unnatural setting
• Korsakoff's syndrome?


  chronic alcoholism - still have STM but no LTM - evidence of different stores in the model

  more natural evidence

  people already have disorder - don't have to wait for accident/ illness - don't inflict on people - not unethical