Forgetting True Memories and Creating False Memories

Psy315 - Classes 27 and 28

(This page last updated 30 March 2009.)

Possible Explanations for Forgetting

• Decay
• Interference
• Retrieval Failure

   Good evidence for retrieval failure. Evidence for interference stronger than evidence for decay.

  • Cockroaches forget less when inactive.
  • Humans forget less when asleep than when awake and active.

Evidence that Memories can be Changed After they are Recorded

• Loftus & Palmer (1974)
  • Leading question with "hit" or "smashed"
  • "Smashed" produces faster speed judgments.
  • Subjects hearing "smashed" more likely to report broken glass later.
• Hyman, Husband,& Billings (1995)
  • Repeated suggestions of nonexistent childhood event.
  • After 3 sessions, 25% of subjects report recall for event.
  • Many of those provide details of event.

Flashbulb Memories

• Highly detailed memories of very significant events.
• Brown & Kulik (1977) studied people's memories of where they were when Kennedy was shot.
• Neisser & Harsch (1992) find large differences in recall of Challenger explosion after 3 years.

Confidence in Memory

• Little connection between memory confidence and memory accuracy.
• Just because someone is confident in a specific memory does not mean that it is more likely to be true.

   

Evidence for Accurate Memory

• Yuille & Cutshall (1986)
  • Interviewed 13 crime witnesses.
  • Reported details about what happened 83% correct.
  • Descriptions of objects 90% correct.
• Recall can improve when more time is available.
• Memory for identities of high school classmates fairly stable for over 30 years.
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Summary

• Most memories are accurate.
• False memories do occur, and it can be very difficult to determine which memories are true and which are false.
  • Confidence can be high for false memories.
  • False memories can have a high level of detail.

next class: Network Models of Memory
  
Psych 315H: Cognitive Psychology Kyle Cave Psychology Dept. U. Mass.