Multi Store Model

• who designed the multi-store model?

  Atkinson and Shiffrin (1968)
• what is the multi-store model?

  - a theoretical cognitive model of how the memory system processes information
• 1st store (sensory register)


  - receives raw sense impressions; attention passes info to STM (short-term memory)

  CODING = modality specific, CAPACITY = very large, all sense impressions in each moment, DURATION = very short (250ms)
• 2nd store (short-term memory)


  - receives info from the SR by paying attention or from LTM by retrieval

  - keeps info in STM by repeating (maintenance rehearsal) or passing info on to LTM by linking it to the info in LTM (elaborative rehearsal)

  CODING = acoustic, DURATION = approx. 18 seconds, CAPACITY = 7+/- 2 items (Miller)
• MILLER - STM capacity


  - digit span technique, lab experiment where ppts given increasingly long lists of numbers to recall

  - when ppts failed 50% of task, they were judged to have reached their capacity: FINDINGS - numbers = 9, letters = 7, recall increased with age
• how is info lost in the STM?


  - via displacement (new info enters the STM)

  - via decay (lost over time)
• 3rd store (long-term memory)


  - very long duration/permanent memory storage with a theoretically unlimited capacity (forgotten info appears just to be inaccessible)

  - coded semantically (in the form of meaning), to use the info it must be passed back to STM via retrieval
• A03 - STM & LTM are separate


  - Glanzer + CUnitz: found words at the start and end of a word list were more easily recalled (primary recency effect)

  - suggest 1st words in LTM and last in STM; however middle words were displaced
• A03 - Coding STM & LTM


  - Baddeley: four 10-word lists given to 4 ppt groups, word lists were acoustically similar or semantically similar

  - found immediate recall was wort for acoustically similar words, and recall after 20mins worst with semantically similar

  - suggests STM is coded acoustically, and LTM is coded semantically
• A03 - Duration STM


  - Peterson and Peterson: found recall of 3 letter trigrams (eg HFR,TKD) was <10% after 18 secs if performing interference task (counting backwards)

  - suggest STM duration is very short, 18-30 secs max
• A03 - artificial


  - cognitive tests of models like the MSM are often highly artificial (low mundane realism) and are conducted in lab environments (low ecological validity)

  - findings may not generalise to day-to-day life
• A03 - criticisms of the model


  - there are different types of LTM and STM

  - the capacity of hate STM can be altered significantly, eg by age or practice, suggesting the view of a fixed STM/LTM capacity is incorrect