Cognitive Psychology

Cognitive Psychology

1. Duration: A measure of how long a memory lasts before it is no longer available. Duration depends on the memory storage of where it is held.

   • Peterson and Peterson (1959) : Duration STM
     • Methodology: Lab Experiment
     • Procedure: 24 Psychology students had to recall random trigrams (e.g DHF). Were asked to count backwards in 3's or 4's starting from a specific number until they saw a red light appear. Then asked to recall trigram after intervals of 3, 6, 9, 12, 18 seconds.
     • Findings:The longer the delay, the lower the number of trigrams that were recalled. 80% recalled after 3 seconds and 10% after 18 seconds.
     • Conclusion: STM has a limited duration if rehearsal is prevented.
     • Strengths
       • Numbers were said out loud --> ensured accuracy/validity
       • Participants were alone --> can't copy
       • Simple --> easy to repeat (reliable)
     • Weaknesses
       • Not representative of the population --> all participants were psychology students (can't generalize)
       • Small sample size --> only 24 students
       • Time only went up to 18 seconds --> doesn't give a definitive answer to the aim as it doesn't say how long it actually took for people to forget
       • Low in mundane realism
   • Bahrick et al. (1975): Duration LTM
     • Procedure: 400 participants aged 17-74 were given tests.
       • Free recall test: Asked to name all the students in their graduating class.