Discuss coding, capacity and duration

• who did research on coding

  Baddeley
• what was Baddeleys procedure for coding

  list of words given to 4 groups, acoustically similar, semantically similar, acoustically different, semantically different
• what did badly find about coding

  STM is encoded acoustically and LTM is encoded semantically
• who did research on capacity (digit span)


  Jacobs
• what did Jacobs find about digit span

  9.3 for digits

  7.3 for letters
• who did research on capacity (chunking)

  Miller
• what did miller find

  capacity is 7+/-2 and we remember things by chuncking them
• who did research on duration of STM

  Peterson and Peterson
• what did P+P find about duration of STM

  18-30 seconds
• who did research into duration of LTM

  Bahrick
• What did Bahrick find about LMT

  after 15 years ppts recall was 90% accurate showing LTM duration is basically unlimited
• artificial tasks


  P+P used trigrams in their research, it is not normal for someone to go around memorising trigrams in everyday life, showing it lacks ecological validity
• good control


  Baddeleys research was done in a lab, therefore giving good control of cofounding variables. giving this good internal validity
• high external validity


  • Bahrick used real life year books and real life photos, therefore they would be meaningful to the ppts.
  • showing that it has good external validity because the stimuli means something to them and its not just random
• confounding variables


  in Bahricks study it doesn't control confounding variable , for example we don't know if the person looked at the year book which would make their recall better to everyone else's