Coding, Capacity, Duration

• Baddeley - limitation - artificial stimuli

  the word lists had no personal meaning to the participants, which tells us little about coding for everyday memory tasks. this is because when processing more meaning information, people may use semantic coding even for STM tasks - suggest that the findings have limited application.
• Peterson + Peterson - Duration

  Method = 24 students in 8 trials, on each trial the students were given consonant syllables to remember, they were also given a 3 digit number, the students counted backwards from this number until told to stop. On each trial they were told to stop after varying periods of time.

  Findings = After 3 seconds, average recall was about 80% after 18 seconds it was about 3%. - suggested that STM duration may be about 18 seconds, unless we repeat the information over and over.
• Peterson + Peterson - limitation

  lacked external validity

  recall of consonant syllables does not reflect meaningful everyday memory tasks
• Bahrick - Duration

  392 participants aged between 17 and 74

  Method =

  1. recognition test - 50 photos from high school yearbooks
  2. free recall test - participants listed names of their graduating class

  Findings = recognition test - 90% accurate after 15 years, 70% after 48 years

  free recall - 60% recall after 15 years, 30% after 45 years -this shows that LTM may last up to a lifetime for some material
• Bahrick - Duration - strength

  high external validity

  everyday meaningful memories were studied when lab studies used meaningless pictures, recall rates were lower - meaning these findings reflect a more 'real' estimate of duration in LTM