Multi store model

• Baddely

  • Created 4 word lists - acoustically and semantically similar and dissimilad
  • Learned a list and immediately asked to recall (stm) and then again 20 mins later (ltm)
  • When testing the stm they performed worst on acoustically similar words showing the stm is coded acoustically and for the ltm they performed worst on the semantically similar words showing ltm is coded semantically
• Jacobs

  • Digit span test
  • Researchers read out a number of digits or letters and had to recite them
  • They on average remembered 7 letters and 9 numbers
• Miller

  • Found that people could roughly absorb 7 +/- 2 pieces of information
  • Could be increased by chunking
• Peterson & Peterson

  • Ppts given 3 letters and 3 numbers (e.g 512 THX)
  • After being given their numbers they were asked to count backwards from their 3 digit number and then asked to recall the consonant syllable after 3, 6, 9, 12, 15 or 18 seconds
  • 80% recall after 3 seconds and 2% recall after 18
• Bahrick

  • 392 Americans aged between 17 and 74
  • Recognition test - 50 photos taken from thier year book
  • Free recall - asked to list names of their graduating class
  • Recognition test - 90% recall after 15 years, 70% after 48
  • Free recall - 80% recall after 15 years, 30% after 48
• Sperling

  • Ppts shown a visual array of 12 letters for 50 milliseconds then asked to recall immediately
  • Avg recall was 4/12 because the info faded so rapidly
• HM

  • Brain damaged caused by a surgery to remove his hippocampus to reduce epilepsy
  • His personality remained the same but he struggled to form new ltms
  • He could still remember ltms from before surgery and performed well when being tested for stm
• Clive Wearing

  • Impaired stm (only 7 seconds)
  • Unable To rehearse new info
  • Can’t remember the question that was asked partway through answering
  • Difficulty retrieving existing ltms which shows that the ltm and stm are two different stores
• KF

  • Impaired stm from a motorcycling accident
  • Difficulty dealing with verbal info but not visual info, suggesting the stm is coded acoustically
• Strengths

  • Baddely - showed fundamental differences between stores coding in stm and ltm
  • Jacob’s study is still valid and has been repeated with similar results
  • Bahricks study has external validity as researchers investigated meaningful memories
• Weaknesses

  • Miller may have overestimated capacity of ltm, Cowan argues it’s more like 4 +/- 1
  • Peterson & petersons study has low external validity as they used meaningless stimuli
  • Takes no account for the nature of info, what we are trying to remember is important to how easy it is to be recalled
• Stm

  • Coding - acoustic
  • Duration - up to 18 secs
  • Capacity - 7 +/- 2
  • maintained in stm through maintenance rehearsal
  • comes from sensory memory by attention
• Ltm

  • Coding - semantic
  • Capacity - unlimited
  • Duration - unlimited
  • transferred from the stm through elaborative rehearsal
• Sensory memory

  • duration - 0.25 to 4 seconds
  • Coding - iconic and echoic
  • Capacity - large