AO1 - Research into Coding, Capacity, Duration

• Coding - this is how we process information, changing it to a suitable form so it can be stored (1) e.g. the STM codes acoustically (1)

  • sensory register: modality specific
  • short term memory: acoustic
  • long term memory: semantic
• Baddeley conducted research into the coding of the STM

  
  

  Aim: to investigate how we code information in our STM (lab experiment)

  Procedure: showed participants lists of words in 4 categories

  • acoustically similar (cat, sat, mat, bat)
  • acoustically dissimilar (tree, house, flour)
  • semantically similar (kip, doze, nap, sleep)
  • semantically dissimilar (cake, book, plane)
  • Immediately after each presentation, participants were asked to recall the lists in the correct order
• Baddeley's findings: more mistakes made on the acoustically similar list

  • Conclusion: suggests the STM mainly codes acoustically
• Baddeley conducted research into the coding of the LTM

  
  

  Aim: to investigate how we code information in our LTM (lab experiment)

  Procedure: showed participants lists of words in 4 categories

  • acoustically similar (cat, sat, mat, bat)
  • acoustically dissimilar (tree, house, flour)
  • semantically similar (kip, doze, nap, sleep)
  • semantically dissimilar (cake, book, plane)
  • 20 minutes after each presentation, participants were asked to recall the lists in the correct order
• Baddeley's findings: more mistakes made on the semantically similar list

  • Conclusion: suggests the LTM mainly codes information semantically
• Capacity - this is the amount of information that can be held in memory (1) e.g. the capacity of the STM is 5-9 items (1)

  • sensory register: unlimited
  • short term memory: 5-9 items
  • long term memory: unlimited
• Miller conducted research into the capacity of the STM

  
  

  Aim: to investigate the capacity of the STM (lab experiment)

  Procedure:

  • he used the "digit span technique"
  • participants were given strings of unrelated digits that increased by one digit every time
  • participants' digit span was measured until the point they could no longer recall the digits in the correct order
• Miller's findings: participants could recall 5-9 items, more could be recalled if the items were 'chunked'

  • Conclusion: capacity of STM is limited (5-9 items), our digit span can be increased by putting several items into a meaningful chunk
• Duration - this is how long the information lasts in memory (1) e.g. information lasts 18-30 seconds in the STM (1)

  • sensory register: limited - less than 0.5 seconds
  • short term memory: limited - 18-30 seconds
  • long term memory: potentially forever
• Peterson and Peterson conducted research into the duration of the STM

  
  

  Aim: to investigate the duration of the STM (lab experiment)

  Sample: 24 undergraduate students

  Procedure:

  • participants were briefly presented with a consonant trigram (e.g. HDF) to remember
  • they were then given a three digit number and asked to count backwards from this number to prevent rehearsal
  • they were stopped at different intervals (3,6,9, etc. seconds) and asked to recall the consonant trigram
• Peterson and Peterson's findings: after 3 seconds, only 80% recalled the trigram correctly, after 18 seconds, fewer than 10% recalled correctly

  • Conclusion: information in the STM lasts for 18-30 seconds unless it is rehearsed
• Bahrick conducted research into the duration of the LTM

  
  

  Aim: to investigate the duration of the LTM

  Sample: 392 American high school graduates aged between 17 and 74

  Procedure: Bahrick tested the sample on their memory of former classmates

  • condition 1 - recall the names of classmates using a photo yearbook
  • condition 2 - recall the names of classmates with no photo cue
• Bahrick's findings: Findings: in condition 1 - 70% of participants recalled accurately after 48 years, in condition 2 - 30% of participants recalled accurately after 48 years

  • Conclusion: certain types of information can potentially last a lifetime, especially with the correct cues