Memory Decay over Time

Implicit vs Explicit

• implicit memory decays slower, explicit faster

Empirical

• Mitchell (2006)

  • n = 33
  • 17 years ago shown pictures for 1-3 seconds
  • test now: 12.5% better memory for implicit, no improvement in explicit memory of those pictures
  • subjects could not remember anything from 17 years ago explicitly when asked, but still remembered having seen those images before
    • Source Monitoring

• Mitchell, Kelly & Brown (2017) (replication)

  • n = 28
  • 11-14 years, pictures and words
  • 12.3% better for pictures, 20.9% better for words, no improvement with explicit memory

Source Monitoring

Source Monitoring

• we tend to forget the source of an information faster than the information

• information from uncredible source can become credible when forgetting source, but not information itself

  • sleeper effect: attitude can change when forgetting the source (Pratkanis et al., 1988)

• confusion between actual / imagined experience and own experience / of someone else

• Gold Mountain Blues case

  • authors Choy, Lee and Yee launched copyright infringement lawsuit against Zhang for copying “substantial elements” of their books
  • Zhang named common events and experiences as basis for her novel

Link to original

Ebbinghaus

• Ebbinghaus 1885/1913

  • n = 1
  • memorize nonsense syllables to find out about forgetting
  • found out about the ebbinghaus forgetting curve
  • re-learning is faster and easier than learning it for the first time

• ebbinghaus forgetting curve

  • if you missed a few slides the best place is right before the exam
  • there is a baseline where nothing is lost
  • after 2 days the most is gone
    • positive: what is still there after 2 days will stay for longer
  • 20 minutes: working memory
  • 2 days: free-floating long-term memory
  • it’s okay to not know everything
    • do you want to know everything for a short period
    • or
    • do you want to remember what you know now for longer times
    • pick 1 of them