Cognitive Psychology - Memory

Cognitive Psychology - Memory

1. Duration

   • STM
     • Peterson & Peterson
       • Method
         • Ppts shown nonsense trigram
           • 3 random consonants
           • Asked to recall after 3, 6, 9, 12, 15 or 18 secs.
             • During pause - asked to count backwards in 3s from given no
               • Interference task
       • Results
         • After 3 secs - about 80% trigrams recalled correctly
         • After 18 secs recall = 10%
       • Conc
         • When rehearsal prevented - very little can stay in STM for longer than about 18 secs
       • Evaluation
         • Lab experiment
           • Variables tightly controlled
             • Results likely to be reliable
         • Nonsense trigrams
           • Artificial
             • Lacks eco validity
             • Meaningful / 'real-life' memories may last longer in STM
         • Only 1 type of stimulus used
           • STM may depend upon stimulus
         • Each ppt saw multiple trigrams
           • Could've led to confusion
             • Meaning 1st trigram was only realistic task
   • VLTMs
     • Bahrick et al
       • Method
         • Field experiment
         • 392 people asked to list names of ex-classmates
           • 'Free-recall test'
           • Shown photos
             • Asked - recall names of people shown
               • Photo - recog test
             • Or given names
               • Asked to match to photo of classmate
                 • Name - recog test
       • Results
         • W/in 15 yrs of leaving school
           • Ppts recall about 90% names & faces
         • About 60% accurate on free - recall
         • W/in 30 yrs - free recall = 30% accurate
         • After 48 yrs - name recog about 80% & photo recog about 40%
       • Conc
         • Shows evidence of VLTMs in 'real life setting'
         • Recog = better than recall
           • May be huge store of info
             • But not always easy to access all of it
               • Need help to get it
       • Evaluation
         • Field experiment
           • High eco validity
             • Hard to control all variables
               • Less reliable
         • No way of knowing why info recalled so well
         • Showed better recall than other studies in LTM
           • May be because info was meaningful
         • Type of info could be rehearsed
           • If still in touch w/ ex classmates / if talk to friends about memories of classmates
             • Results can't be gen to other types of info held in LTM
             • Increasing rates of recall