PS 1507 Memory Forgetting

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PS 1507 MemoryForgetting

• Lecture 4
• Caroline Green

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Forgetting

• Ebbinghaus forgetting curve. Initial rapid
  forgetting followed by decrease over time. (sin
  of transience) Holds for material learned decades
  before. (Bahrick(1984), Conway et al (1991),Cohen
  et al(1992)).
• Notion of permastore (Bahrick,1984).
• Neisser(1984)- conceptual knowledge better
  retained than facts.

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Figure 8.21 The forgetting curve for Spanish
vocabulary. Source Adapted from Bahrick, H.P.,
Semantic memory content in permastore Fifty
years of Spanish learned in school. Journal of
Experimental Psychology (General), 1984, 113,
129.
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Memory decline

• Conceptual knowledge better retained than facts
• Memory declines over 3 years then stabilises
  (Bahrick(1984),Conway(1992))
• Ageing story recall declines first, word recall
  later. Transience more marked after 60. Higher
  education may alleviate effect

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The brain and transience sites implicated

• Hippocampus inner parts of temporal lobe
  important
• Also parts of frontal lobe

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Why do we forget? Theories.

• Trace decay theory
• Interference theory
• Cue-dependent forgetting/encoding specificity
• Context-dependent /State-dependent memory
• Repression/motivated forgetting

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Trace decay theory

• Memory traces decay or fade spontaneously over
  time.
• Time elapsed since learning is of crucial
  importance.
• Jenkins and Dallenbach (1924) found evidence
  against theory.

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Interference Theory

• Forgetting caused by interference of 2 types
• Retroactive - new memories interfere with old
• Proactive old memories interfere with new
• Greater similarity greater forgetting.
• Does not always apply well to everyday life

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Cue-dependent forgetting/encoding specificity

• Cue dependent forgetting - retrieval cues missing
  or not used.
• TOT
• Encoding specificity principle better recall
  when cues present at encoding also present
  during retrieval.

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Tip of the Tongue (TOT) phenomenon - not for
students

• Sin of blocking
• Near universal experience
• Peoples names worst affected
• Worse with age

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Context and state dependent memory

• Context dependent memory
• (Godden and Baddeley(1975) scuba divers,
  Marian and Neisser(2000)- Russian immigrants)
• State dependent memory
• (Miles and Hardman, 1998 bicycle ergonometer).
  
• Mood dependent memory
• (Eich, 1995)

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Motivated forgetting/ Repression

• Motivated forgetting tendency to forget things
  one doesnt want to think about
• Repression process by which emotionally
  threatening experiences are banished to the
  unconscious mind (Freud (1901))
• Contradictory evidence Loftus Burns(1982)
  found effects, no effect (Bradley
  Baddeley(1990)), better memory for traumatic
  events (Christianson Loftus(1987).

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Absent-mindedness prospective memory

• Inattention to details/Lapses of attention
  produce(s) encoding failure causing slips of
  memory.
• Occurrence of memory slips

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Slips of memory occur with

• Familiar surroundings
• Preoccupation
• Other distractions
• Pressure of time
• Changes to established routine
• Age
• Time based tasks more than event based tasks