Duration

Duration

1. Short Term Memory

   • Peterson & Peterson
     • Participants given a trigram & a 3 digit number to count back from
       • Number prevented rehearsal
       • Length of time of counting increased with each trial
       • Then had to recall the trigram
     • Limitation; Lacks External Validity - does not reflect real memory activities
     • Findings show STM has a very short duration
       • After 3 secs, 80% remembered,
       • After 18 secs, 10% remembered

2. Long Term Memory

   • Bahrick
     • Obtained yearbooks from 392 participants
     • Tested recall in 2 ways
       • Photo recognition (Some photo's from yearbook)
       • Recall of names of their graduating class
     • Findings
       • Graduated within 15 years
         • 90% Accurate with photo recognition
         • 60% accurate with names
       • Graduated within 48 years
         • 70% accurate with photo's
         • 30% accurate with names
       • LTM is very long
     • Limitation: Confounding variables had not been controlled, so participants could have looked at yearbook over the years, rehearsing their memory
     • Strength: High External Validity - real memories were used.
       • Meaningless pictures had lower recall rates

3. Duration is the length of time information can be held in memory