Forgetting

One view of forgetting is that memories disappear over time. They are vivid when originally store but become fainter as time goes on. Although this is a good observation about how we feel about memory, it would be about the same as saying that rust occurs because of time.

Rust occurs because of oxidization, which gets worse over time. It is not time itself that causes rust. Memories get worse over time but what is the memory’s equivalent of oxidization?

Here are 5 things we’ll cover:

• Forgetting Principles
• Interference
• Three Mechanisms
• Amnesia
• Memory Fialures

 

Terms

• accessible memories
• amygdala
• anterograde amnesia
• Atkinson & Shiffrin
• automatic processing
• available memories
• Baddeley
• basal ganglia
• cerebellum
• chunking
• deep processing
• déjà vu
• distributed practice
• Ebbinghaus
• echoic sensory store
• effortful processing
• emotional coding
• encoding
• encoding failure
• encoding specificity principle
• episodic memory
• explicit memories
• external mnemonics
• false memory
• flashbulb memories
• forgetting
• forgetting curve
• herpes encephalitis
• hierarchies
• hippocampus
• iconic sensory store
• implicit memories
• improving memory
• interference
• levels of processing
• long-term memory
• long-term potentiation
• match context and mood cues with when coded them
• meaningful
• memory
• memory retrieval
• misinformation effect
• mnemonics
• mood congruent
• motivated forgetting
• personally meaningful
• priming
• proactive interference
• recall
• recognition
• reconsolidation
• recovered memories
• recovered with hypnosis
• rehearse repeatedly
• relearning
• repression
• retrieval
• retrieval cues
• retrieval failure
• retroactive interference
• retrograde amnesia
• savings
• semantic memory
• sensory memories
• serial position effect
• shallow processing
• short-term memory
• sleep more
• source amnesia
• spaced practice
• split brain
• storage
• storage decay
• synaptic changes
• technical mnemonics
• test your knowledge
• testing effect
• tip of the tongue
• unreliable memories
• Wearing, Clive
• working memory

Quiz

Interference theory was:

• a. based on associationism
• b. relatively atheoretical
• c. introduced by McGeoch
• d. all of the above

 

2. Ebbinghaus showed that verbal learning is:

• a. protracted
• b. stratified
• c. linear
• d. all of the above

3. Bahrick calls long-lasting memories:

• a. sustained saturation
• b. permastores
• c. artifacts
• d. hodos

4. Given a picture and asked to decide it if is a former classmate is:

• a. picture recognition
• b. picture registration
• c. linear recognition
• d. name recognition

5. Which is part of semantic memory

• a. general information
• b. nonsense syllables
• c. foreign languages
• d. all of the above

Interference theory was:

• a. based on associationism
• b. relatively atheoretical
• c. introduced by McGeoch
• d. all of the above

2. Ebbinghaus showed that verbal learning is:

• a. protracted
• b. stratified
• c. linear
• d. all of the above

3. Bahrick calls long-lasting memories:

• a. sustained saturation
• b. permastores
• c. artifacts
• d. hodos

4. Given a picture and asked to decide it if is a former classmate is:

• a. picture recognition
• b. picture registration
• c. linear recognition
• d. name recognition

5. Which is part of semantic memory

• a. general information
• b. nonsense syllables
• c. foreign languages
• d. all of the above

 

1. Forgetting Principles

• Some things are easier to forget than others
• How much you forget depends on the knowledge domain
• store things in various memory systems
• retrieve them with various levels of success
• Ebbinghaus
  • Not good at remembering nonsense syllables or isolated words
    • verbal learning is linear
    • forgetting verbal learning is nonlinear
  • Learning is a function of time spent
    • longer you study the more you learn
  • Forget the majority of facts very quickly
    • within the first few hours
    • after the first day, decline is more gradual

2. Forgetting Theories

• Predominant approach in N. America for 30 yrs
• Based on associationism
  • learning = formation of associations between previously unrelated events
• Developed in Chicago in the 1930s (Carr, Robinson and McGeoch)
  • relatively atheoretical
  • good research, not much theory
• McGeoch (1932)
  • First to propose interference theory
  • Time-based decay theories not valid explanations
  • Iron rusts over time
    • time does not cause rust
    • oxidation causes rust
  • Memories are forgotten over time
    • time does not cause forgetting; caused by something else
  • 2 kinds of interference
  • Proactive interference
    • previous info impacts new
  • Retroactive interference
    • new info impacts old
    • retrieval errors occur because wrong memories found
  • Cue Dependent Theory (Retrieval Failure)
    • Forgetting is lack of retrieval cues, not overwriting existing info (Tulvig & Postka, 1971)
    • Ss given list of 24 words (4 items in six categories)
    • try to recall as many as possible
    • Learn 0, 1, 2, 3 or 5 further lists (3 trials), immediate free recall
    • Recall as many words from any lists
    • Clear evidence of RI
      • more lists in the middle, worse did
      • Ss tend to forget whole categories
      • 10 minute break
      • give categories, asked to recall
    • Performance as good as original free recall
      • no effect of interpolated lists
    • Can’t recall because $ is missing
      • present at time of encoding
      • not erased; not available
      • proper cue can retrieve it
      • like searching for a book in the library
      • no reference number
      • no subject
      • no author

    Good retrieval cue

    • consistent with encoding situation
    • If a word is emphasize during encoding
    • Should be emphasized at test time

    State Dependent Cues

    • retrieval depends on state of mind
    • at encoding & at testing
    • Memory triggered or facilitated by:
    • inebriated
    • anxious
    • happy

    Context Dependent Cues

    • retrieval depends on environment
    • at encoding & at testing
    • Memory triggered or facilitated by:
      • under water
      • weather
      • location
      • smell

    Trace Decay Theory

    • Learning causes neuro connection
      • trace degrades over time, recall is worse
      • except notice that if brain is injured, old memories more resistant than new ones (Brower, 1967)
      • crumbling into parts; loss of components
      • both interference and decay
    • Problem:
      • time has both decay & interference  (aren’t doing nothing over time)

    Consolidation

    • Learning is not complete when practice ends (Muller and Pilzecker (1900)
      • perseveration occurs for awhile afterward
      • perseveration = continued processing of an item after practice or rehearsal ends.
    • If anything interrupts perseveration
      • memory trace may not consolidated
      • recall not possible
      • storage problem
    • Longer perseveration continues, stronger the memory
      • if process is interrupted, no storage
    • Assumptions
      • mental inactivity helps consolidation (Ebbinghaus, 1885)
      • rate of forgetting is slowed when sleep between study & test (Jenkins & Dallenbach, 1924)
      • Ss can recall more after a period of sleep
    • Interference model would say the same thing
      • if interrupted, nothing stored
      • Ss with retrograde amnesia:
      • can’t remember events right before trauma
      • perseveration interrupted by the trauma
      • consolidation not completed
    • Rats with induced retrograde amnesia show better memory performance if allowed perseveration time
      • If prevented, no storage
    • No good studies with humans on the issue
      • Not easy to prevent unless remove hippocampus

3. Three Mechanisms

1. Response competition
   • when 2+ potential responses to a memory query
   • Melton & Irwin (1940) showed errors could not be attributed solely to intrusion items
2. Altered $ conditions (altered context)
   • performance declines because of changes in environment from study to test
   • functional $ is cue + environment
   • forget if entire functional $ not present
3. Mental set
   • use an inappropriate mental set
   • search through wrong list

Part-set cuing

• Ss recall list worse if some items (part of the set) are provided for them (Slamecka, 1968)
• Ss hear a word twice
• control Ss wrote as many words as could
• experimental Ss were given a paper with some of the words on it
• Ss who receive some words did worse
• maybe the cues interrupt retrieval strategy
• Predictor but not cause of forgetting

• McGoeoch & McDonald (1931)
  • systematically vary similarity of interfering activity & recall material
  • learn list of adjectives
  • 10 min rest or learn new material
  • as similarity increases, recall drops
  • but even resting Ss forgot some too
• (Slamecka, 1960): sentences
  • 2, 4, 8 trials
  • followed by rest or 4 or eight trials learning another literary genre
  • amount learned is a function of # of initial learning trials
  • amount of forgotten is function of number of interfering trials

4. Amnesia

• forgetfulness; without memory
• Caused by
  • brain damage
  • disease
  • drugs (sedatives & hypnotic)
• can be either wholly or partially lost
• Two main types (not mutually exclusive)
  • Retrograde amnesia
    • inability to retrieve info acquired before a particular date
    • loss can extend back decades
    • lose can last for months+
  • Anterograde amnesia
    • inability to transfer new info to long-term memory
    • can’t remember things for long periods of time
  • Post-traumatic amnesia
    • Major trauma
      • usually head injury (fall, football, boxing)
      • often transient but may be permanent
    • Mild trauma
      • car crash
      • no memory of moments before accident
    • Childhood amnesia (infantile amnesia)
      • can’t remember before age 2-3
      • brain not developed enough to hold cognitive structures
    • Transient global amnesia
      • unknown cause
      • memory loss for less than a day
      • reduced blood flow, seizure or migraine?
    • Source amnesia
      • can’t remember where learned information
      • poor source monitoring
      • source not encoded
    • Hyped but Non-Existent
      • Dissociative amnesia
        • can’t remember because of psychological trauma
      • Types:
      • Repressed memory (psychogenic amnesia)
        • inability to recall info about stressful or traumatic events
        • rare or doesn’t exit
      • Dissociate fugue (psychogenic fugue)
        • cannot recall some or all of past
        • extremely rare or doesn’t exist
      • Posthypnotic amnesia
        • failure to remember suggestions made under hypnosis
        • extremely rare or doesn’t exist

5. Memory Failures

• Time-Gap
  • no conscious recollection of trip
  • driven home late at night
  • driving well-traveled route
  • highway hypnosis; driving long stretches
• Cryptomnesia
  • unintended plagiarism
  • believe have made a novel creation but it’s based on earlier works
  • failure to recognize it as familiar
  • usually of others
  • Nietzsche, Freud, Helen Keller
  • George Harrison
    • My Sweet Lord by the Beatles
    • He’s So Fine by the Chiffons
  • How guard against it
  • can’t but can try to minimize by searching literature & peer review