multi store model of memory

• Coding


  The process of entering information into memory and how it is written in a particular format/code
• Types of memory codes

  • Visual (image)
  • Acoustic (sound)
  • Semantic (meaning)
• Capacity


  The amount of storage space available in memory, measured by the number of items that can be held at any one time
• Duration


  How long information lasts before it is no longer available, may be available for less than a second or many decades
• Multi-store model


  • Suggests that information flows through 3 memory stores: Sensory, Short-term, and Long-term
  • Makes 3 assumptions about memory: 3 separate stores, stores are unitary, information is transferred through rehearsal
• Sensory register


  • Consists of several, one for each of our senses
  • Iconic Store (coded visually)
  • Echoic Store (coded acoustically)
  • Duration for iconic is 12 seconds, duration for echoic is 2 seconds
  • Capacity is large, but attention must be paid for information to pass on to STM
• Short-term memory


  • Holds between 5 and 9 items at any one time
  • Coding is acoustic
  • Maintained via rehearsal
  • Duration is about 30 seconds
  • If information is rehearsed it passes on to long-term memory
• Long-term memory


  • Capacity and duration is potentially many years
  • Coded semantically
  • Information can be forgotten through decay, interference and retrieval failure
  • Recall information to STM (retrieval)
• Memory


  Separate stores
• Sensory register


  Iconic store and echoic store
• Sperling's (1960) method


  1. Investigated capacity and duration of iconic store

  2. Used a tachistoscope, grid of 12 symbols for one-twentieth of a second

  3. After letter, sounded a high, medium or low tone

  4. Participant had to recall the high, medium or low tone
• Brown-Peterson technique


  1. Presented with diagrams and asked to remember them

  2. To prevent rehearsal, had to count aloud, backwards and in 3s

  3. Then had to recall the diagrams - findings - 3s = 80% correctly recalled, 9s = 30% and 18s = 10%
• Some people can retain items for up to 30 seconds (maximum duration for short-term memory)
• Jacobs' research


  1. Presented lists of digits at 1/2 second intervals

  2. Participants had to repeat the list in order

  3. Started with 3 items, increased 1 length at a time until participants couldn't recall the list

  4. Repeated to obtain average number of items recalled (digit span)
• Coding in short-term memory

  Acoustic code
• Conrad's research


  1. Investigated coding in short-term memory

  2. Presented random sequences rapidly

  3. Participants wrote down letters in correct order

  4. Either acoustically similar or dissimilar - found it harder to recall acoustically similar words than dissimilar words, suggesting the STM has an acoustic code
• Bahricks et al.'s research

  1. Investigated duration of long-term memory

  2. 392 graduates, traced over 2 weeks to 57 years

  3. Selected 130 pictures from each yearbook

  4. Free recall of names, recognition of names, recognition of pictures, matching pictures to names, matching names to pictures, naming pictures
• Baddeley's research


  1. Investigated coding in long-term memory

  2. Presented 70 young servicemen with the same 5 words in different orders

  3. Had to write down words in correct order

  4. Groups: acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar
• Sperling - findings


  if the tone was in a quarter of a second, the participants recalled 3/4 of symbols from any row

  if there was a one second delay, only 33% of information was recalled

  conclusion: capacity = 75%, the duration is one second
• case study of HM

  underwent brain surgery to remove his hippocampus, his memory was impaired in the process. Due to this, he was unable to produce new LTM. However, his STM was unaffected. This suggests that memory isnt one unitary store.
• Bahrick - findings 


  free recall of names = 50% at 3 months, dropped to 20% after 40 years

  recognition of names, pictures and matching pics to names = 90%

  naming pics = 70% at 3 months, 60% at 15 years and 20% at 40 years
• baddely - findings


  no difference between acoustically similar/dissimilar words

  semantically similar = 55%

  semantically dissimilar = 85%

  this suggests that LTM uses a semantic code
• Strengths of MSM


  evidence that STM and LTM are different - jacobs (capacity) baddely = STM is acoustic and LTM is semantic

  evidence that STM and LTM are separate (case study of HM)

  practical applications - helps students with revision (maintenance rehearsal)
• limitations of MSM


  STM and LTM have multiple components, theyre not unitary and each component is capable of processing different types of information (WMM)

  rehearsal isnt always required for transferal, sometimes we remember things we havent rehearsed (hyde and jenkins - no difference between group who knew they had to recall and group who didnt)