coding, capacity and duration

• what is the definition of coding?

  format in which info is stored
• what is the definition of capacity?

  the amount of info that can be stored in the memory
• what is the definition of duration?

  length of time info can be held in memory
• who investigated coding?

  Baddeley
• how did Baddeley investigate coding?

  got four groups of people and gave them a list of words to remember in order

  G1 - acoustically similar words

  G2 - acoustically dissimilar words

  G3 - semantically similar words

  G4 - semantically dissimilar words
• what did Baddeley find out?

  STM codes accoustically

  LTM codes semantically
• what is one strength of Baddeley's investigation?

  showed there is a difference between the STM and LTM which was an important step in understanding memory
• what is one limitation of Baddeley's investigation?

  used artificial stimuli --> word lists that had no meaning so doesn't reflect everyday life --> limited application
• Which two people investigated capacity?

  Jacobs

  Miller
• how did Jacobs investigate capcity?

  - measured the digit span by a researcher reading a list of 4 digits and then the participant has to recall in the right order

  - the researcher adds on one more digit and so on until the participant can't recall anymore
• what did Jacobs find out?

  mean span for digits was 9.3 items

  mean span for letters was 7.3 items

  he found out that digits are recalled better on average in the STM
• what was a strength of Jacobs investigation?

  it has been replicated showing his test is a valid test of digit span in the STM
• how did Miller investigate capacity?

  he made the assumption that we remember in groups of 7
• what did Miller find out?

  that the capacity of the STM was 7 +/- 2 items
• what was one limitation of Miller's investigation?

  he overestimated the STM capacity
• who investigated duration in the STM?

  Peterson and Peterson
• how did Peterson investigate duration in the STM?

  - tested 24 students in 8 trials

  - on each trial the student was given a consonant syllable and a number that they had to count down from in 3s for a certain amount of time (3s, 6s, 9s, 12s, 15s, 18s, 21s)

  - after being told to stop they had to recall the letters
• what did Peterson find out?

  after 3s the average recall was 80%

  after 18s the average recall was 3%

  --> STM duration is about 18s unless we repeat over and over
• what is one limitation of Peterson's investigation?

  stimulus material was artificial so lacked external validity
• who investigated duration in the LTM?

  Bahrick
• how did Bahrick investigate duration in the LTM?

  - 392 American participation aged 17-74 were tested on recall of their high school class in 2 ways

  1) photo recognition test from year books

  2) free recall test where they had to recall names
• what did Bahrick find out?

  PHOTO RECOGNITION:

  - participants within 15 years of graduation were approx 90% accurate

  - after 48 years photo recall was approx 70% accurate

  
  

  FREE RECALL

  - participants within 15 years of graduation were approx 60% accurate

  - after 48 years participants were 30% accurate

  
  

  --> LTM has the potential to last a lifetime
• what was a strength of Bahricks investigation?

  has external validity so is a 'real' estimate