Introduction to Cognitive Psychology - Department of Psychological ...

Prof. Greg Francis 8/16/11Significance!! Ebbinghaus’ results suggest that memories canlast a very long time, in some form!! Memories were believed to be “stored” in a memorysystem and did not just fade away (otherwise, thecurve should not asymptote above zero)!! Memory loss was believed to be due to interference ofother memories!! Other experiments challenge this viewMemory task!! See (or hear) a trigram of consonants!! Report it back in order!! Ebbinghaus’ results suggest goodmemory until other letters are alsomemorizedWRMPurdue UniversityPurdue UniversityRetention!! Peterson & Peterson (1959)!!Brown (1958)!! Give subjects trigram!!ask them to count backwards by 3’s andthen recall trigram779, 776, 773,...WRM 782Purdue UniversityRetention!! Vary duration of counting backward!! Numbers are different from letters, youmight not expect any interference!!but they can have very strong interferenceSuggestssome memorieslast only afew seconds!Proportion correct10.80.60.40.200 3 6 9 12 15 18Retention interval (seconds)Purdue UniversityRetention!! The results of the Brown-Peterson studysuggest that some aspects of forgettingare process driven!!keeping a memory “active” requires effort!!if you are distracted by another task, youcannot apply the effort to keep the memory!!similar to our observations about attentionand processingRetention!! The results of the Brown-Peterson study alsosuggest that some aspects of forgetting arepassive!! even if you are distracted, you can recall the trigram ifonly a short time has passed!! if many seconds have passed, while you aredistracted, you cannot recall the trigram!! memory has “decayed”, or something like decay, whileyou were doing the distracting taskPurdue UniversityPurdue UniversityPSY 200: Intro. to Cognitive Psychology 2