Multi-store model

• what are the 3 parts of the multi-store model?

  Sensory register, short term memory, long term memory
• modality specific

  storing something in the mode we received it
• 2 main stores in the sensory register + functions

  iconic memory - visual info is coded visually

  echoic memory - sound info is coded acoustically
• capacity and duration of sensory register

  capacity - very high

  duration - less than half a second
• capacity, duration and coding in STM

  capacity - 4 chunks

  duration - 18-30 seconds

  coding - acoustic
• capacity, duration and coding in LTM

  capacity - unlimited

  duration - lifetime

  coding - semantic
• 4 methods of information processing

  Attention, transfer, retrieval, rehearsal
• strength of MSM

  supporting evidence e.g. Baddeley, Jacobs, Bahrick
• weaknesses of MSM

  • too simplistic
  • case study of KF suggests there is more than one type of STM
• Jacob’s (1887)

  • measured digit span
  • Ppts are given a list of digits, each time increasing by one until they can’t recall the list correctly
  • This determined their digit span

  Mean span for digits: 9.3

  Mean span for letters: 7.3
• problems with Jacobs’ research

  • temporal validity - conducted in the 1800s
• Miller (1956)

  • suggested that things come in 7s e.g. seven deadly sins, seven days in a week
  • capacity of STM is about 7 items

  ‘magic number 7 plus or minus 2‘
• problems with Miller’s research

  • inaccurate - overestimated the capacity of STM - Cowan reviewed his study and said the capacity is actually 4 chunks
• Peterson & Peterson (1959)

  Investigated duration of STM

  • ppts were given a trigram and a 3 digit number to remember
  • They counted down from the number until they were asked to stop then recalled the trigram

  Findings: the longer they counted down, the less accurate recall of the trigram was

  Conclusion - STM has a duration of 18 - 30 seconds
• problems with Peterson & Peterson’s research

  ecological validity - artificial task and stimulus so not representative of memory tasks in everyday life
• Bahrick et al (1975)

  investigated duration in LTM

  • over 300 ppts from Ohio recalled names from their high school year book

  findings: ppts were able to recall some names accurately from a long time ago

  conclusion: LTM can last for a lifetime
• Baddeley (1966)

  investigated coding in STM and LTM

  • 4 groups were given lists of words to remember: acoustically similar or dissimilar, or semantically similar or dissimilar

  findings: when recalling the words immediately, the acoustic group did better, when recalling after 20 minutes, the semantic group did better