Multi-Store Model

Multi-Store Model

1. Atkinson & Shiffrin

2. Coding in STM & LTM

   • Baddeley
   • 4 groups of ppts, each given a different word list
   • Condition 1: acoustically similar list (cat, cab, can)
   • Condition 2: acoustically dissimilar list (pit, few, cow)
   • Condition 3: semantically similar list (great, large, big)
   • Condition 4: semantically dissimilar list (good, huge, hot)
   • STM
     • Ppts shown original word list & asked to recall the list immediately
   • LTM
     • Ppts asked to recall original list after 20 mins
   • Findings
     • Tended to do worse on semantically similar list

3. Capacity in STM

   • Jacobs
     • Ppts given strings of unrelated digits that increase by one digit each time
     • Digit span measured when ppts could no longer recall digits in the correct sequence
     • Mean digit span was 9.3, mean span for letters was 7.4
     • Capacity limited to 7 give or take 2 items
   • Miller
     • Digit span can be increased by 'chunking'

4. Duration in STM

   • Peterson & Peterson
   • Each ppt took part in 8 trials
   • Ppts shown a nonsense trigram (YCG) and then immediately after a 3 digit number
   • Ppt told to count backwards from their 3 digit number until told to stop (prevented rehearsal)
   • On each trial they were told to stop after a different amount of time (3 secs, 6, 9, 12 etc) - called the retention interval
   • Found ppts were 90% correct over 3 seconds, but this diminished over time
   • Only 2% ppts correctly recalled trigram after 18 secs
   • Suggests STM has duration between approx. 18-30 secs

5. Duration in LTM

   • Bahrick
   • 392 American high school grads tested on memory of former classmates
   • Condition 1: Matching names to photos
   • Condition 2: Recalling names with no photo cue
   • Found when tested after 15 years ppts were 90% accurate in naming classmates
   • After 48 years recognition dropped to 70%
   • Shows LTM can last a long time