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Memory
Robert L. Randall, PhD
Retrieval
Refers to process of accessing, or retrieving, stored info.
Vast difference between what is stored in LTM and
what can actually be accessed.
In many instances, what can be retrieved from LTM
hinges upon appropriate retrieval cue.
Retrieval Cue: Clue, prompt, or hint that helps trigger recall
of a stored memory.
Much info not lost, simply inaccessible until appropriate cue
helps “jog” your memory.
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Tip-of-tongue Experience
Inability to retrieve info absolutely sure is stored in LTM.
About half the time people can identify
- First letter of the target word.
- Number of syllables in the word.
Can often produce words with
- Similar meanings as the target word
- Similar sounds as the target word.
About 90% of tip-of-the-tongue experiences resolved.
- Often within minutes.
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Tip-of-tongue Experience
Tip-of-tongue experiences illustrate retrieving information not
all-or-nothing process.
Often remember bits & pieces of information.
- Information stored in long-term memory, however,
not accessible without right retrieval cues.
Tip-of-tongue experiences also demonstrate information
stored in long-term memory
- organized and connected in logical ways.
As mentally struggle to retrieve blocked information, logically
connected bits of information act as additional retrieval cues,
helping to access desired information.
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Testing Retrieval: Three Methods of Retrieving from LTM
Free Recall: Essay Questions
Other than question, no retrieval cues to “jog” memory.
Most difficult form of retrieval.
Cued Recall : Fill-in-the-Blank, Matching Questions
Remember information in response to retrieval cues.
Less difficult than Essay Questions.
Recognition: Multiple Choice Questions
Identify information from several possible choices.
If information in LTM, should be able to recognize.
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Serial Position Effect
Tendency to retrieve information more easily from the
beginning and end of a list rather than from the middle.
Two parts of the serial position effect.
● Primacy Effect
● Recency Effect
Primacy Effect
Tendency to recall the first items in a list.
Recency Effect
Tendency to recall the final items in a list.
Primacy effect particularly prominent when engaging in
serial recall – remember list of items in original order.
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Encoding Specificity Principle
Encoding Specificity Principle
As a general rule, closer retrieval cues match original
learning conditions, more likely retrieval will occur.
Examples:
●
●
Context Effect
Tend to remember information more easily when retrieval
occurs in same setting as original learning.
Mood Congruence
Tendency that given mood evokes memories consistent
with that mood. Specific emotional state can act as a
retrieval cue that evokes memories of events involving
same emotion.
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Flash Bulb Memories
Tendency that highly unusual, highly surprising events
easier to retrieve from memory than routine events.
These flashbulb memories sometimes shared by
large number of people in a given culture.
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Art Glenberg, professor at the University of Wisconsin,
suggests psychologists drop the widely accepted view
that human memory works like computer memory.
How memory really works is still totally up for grabs.
Theories on memory draw from limited knowledge of the
human mind.
Glenberg argues human memory is a direct result of action:
How the body moves & responds to its environment.
Memory exists to help us walk, talk, run, drive a car, answer
the phone, & the myriad tasks of getting along in the world.
His theory was not universally accepted, to put it lightly.
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October 19, 2006 -- Researchers at the Translational
Genomics Research Institute (TGen) announced the
discovery of a gene that plays a significant role in memory
performance in humans.
First study to describe scanning the human genetic blueprint
to identify cognitive differences between humans.
“We can now use this new understanding to develop drugs
that will improve memory function."
"Functional brain imaging techniques showed individuals w/
a version of the gene related to poorer memory potential had
to tax their brains harder to remember the same amount of
information," Dr. Dominique de Quervain, professor,
University of Zurich.
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Current studies strongly support notion that a memory is a
set of encoded neural connections.
Encoding can take place in several parts of the brain.
Thus, neural connections are likely to go across various
parts of the brain.
The stronger the connections, the stronger the memory.
Recollection of an event can occur by a stimulus to any of
the parts of the brain where a neural connection for the
memory occurs.
If part of brain damaged, access to any neural data that was
there is lost.
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Strong evidence for distinct elements of memory which
involve different parts of the brain:
Hippocampus for Short-term Memory.
Amygdala for emotional memories.
Memories might be analogous to a collage or jigsaw puzzle
rather than to "tape recordings," "pictures", or "video clips"
stored as wholes.
According to this model, perceptual or conscious experience
does not record most sense data.
What is stored are bits & fragments of experiences.
Exactly how they are encoded is not completely understood.
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“Collage or jigsaw puzzle model of memory rejects idea that
individual memories stored in distinct locations in the brain.
Distinct Location Model seems to have become solidified by
Wilder Graves Penfield's experiments (1950s) in which
electrodes placed on surface of exposed temporal lobes of
patients & "memories" elicited in 40 of 520 patients.
- However, this is only 7.6% of the patients.
- And, no support for claim “memories” were elicited and
not a hallucination or fantasy.
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Forgetting
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Forgetting
Forgetting defined by psychologists as the
Inability to remember information previously available.
Note: This definition does not refer to the
“loss” or “absence” of once-remembered information.
Tempting to think of forgetting as simply the
gradual loss of information from LTM over time, this
intuitively compelling view of forgetting much too simple.
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Hermann Ebbinghaus (1850 – 1909)
Ebbinghaus' goal
To determine amount of information
forgotten after different time intervals.
Therefore, Ebbinhaus created new
material to memorize.
- Thousands of nonsense syllables.
Three-letter combinations made up of
- 2 consonants
- 1 vowel.
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Hermann Ebbinghaus (1850 - 1909)
Ebbinghaus' used himself as a subject.
Ebbinghaus noted number of times he had to repeat a list
of 13 nonsense syllables before could recall list perfectly.
Once Ebbinghaus had learned the nonsense syllables.
- Tested his recall after varying amounts of time.
* Ranging from 20 minutes to 31 days.
- He plotted his results in the now-famous
* Ebbinhaus Forgetting Curve
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Remembered less than 40% after 9 hours. Then forgetting leveled off.
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Forgetting
Although have identified several factors involved in forgetting:
– Exactly how or why forgetting occurs still actively studied
and debated by memory researchers.
Factors that contribute to forgetting:
(1) Encoding Failure
(2) Retrieval Cue Failure
(3) Decay Theory
(4) Interference Theory
(5) Motivated Forgetting
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(1) Encoding Failure
Information never encoded into LTM in the 1st place.
- One of most common reasons for forgetting information.
Penny Example.
Encoding failure explains why you forget a person's name
3 minutes after being introduced.
- Information momentarily present in short-term memory,
but never encoded into long-term memory.
Encoding failure helps explain absent-mindedness.
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(2) Retrieval Cue Failure
Prospective Memory
Prospective memory failures due to retrieval cue failure.
- Inability to recall information due to missing / inadequate
retrieval cues.
Older adults actually found to be better at prospective
memory than younger adults.
- More motivated, more experience w/ time management.
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(3) Decay Theory
According to the Decay Theory of forgetting, memories
fade over time as a matter of normal brain processes.
Metabolic processes of brain thought to erode memory
trace over time especially if not “refreshed” by rehearsal.
Fading of memories analogous to fading of newsprint
or billboards exposed to elements.
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(3) Decay Theory
Decay Theory makes intuitive sense.
However, much evidence contracts this theory.
(1) Ebbinhaus Forgetting Curve: If memories simply faded
w/ time, expect to see a steady decline in remembered
information w/ passage of time.
(2) Many studies have demonstrated that information can
be remembered decades after learned, even when not
rehearsed or recalled since first learned.
(3) Presentation of retrieval cues would have no effect on
retrieval of info or events from distant past.
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(4) Interference Theory
According to the Interference Theory of forgetting,
one memory competes w/ or replaces another memory.
Critical factor – similarity of information.
- Similar info in 2 memories increases probability of
interference.
Two basic types of interference.
- (A) Retroactive Interference
New memory interferes w/ old memory.
- (B) Proactive Interference
Old memory interferes w/ new memory.
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(5) Motivated Forgetting
Idea that we forget because we are motivated to forget,
usually because memory is unpleasant or disturbing.
Two types of motivated forgetting have been proposed.
(A) Suppression
Deliberate, conscious effort to forget information.
(B) Repression
Motivated forgetting that is done unconsciously.
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(5) Motivated Forgetting
(B) Repression
Motivated forgetting that is done unconsciously.
Great deal of supportive evidence that the more traumatic
an experience, the more likely one is to remember it.
When person fully conscious & healthy brain when
experience a trauma, likelihood forget trauma nearly zero,
unless very young or experience a brain injury.
Idea that sexual abuse is usually unconsciously repressed
and that psychological problems in adulthood are caused
by the unconscious memory of childhood abuse not
supported by scientific evidence.
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Additional reason for forgetting may be related to dreaming:
During sleep, brain may turn day's events into dreams.
Dreams may allow brain to examine events & make sense
of them.
Brain may erase some events & add others to memory bank.
Chances of remembering improve by “consolidation,"
which creates strong encoding.
Thinking & talking about an experience enhance chances
of remembering it.
One of better known techniques of remembering involves
process of association.
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Imperfect Memories
Human memory does not function like a video recorder.
Instead, memory details can change over time.
Without conscious awareness, details can be
- Added, Subtracted, Exaggerated, Downplayed.
Every person has potential to confidently & vividly remember
details of some event & be completely wrong.
Confidence in memory no guarantee accuracy.
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Imperfect Memories: Misinformation Effect
Misinformation Effect
Elizabeth Loftus (1974) had subjects:
- Watch a film of an automobile accident.
- Write a description of what they saw.
- Answer a series of questions.
- One critical question:
'About how fast were the cars going when they contacted
each other?'
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Imperfect Memories: Misinformation Effect
'About how fast were the cars going when they contacted
each other?'
5 Groups: Differed in wording of question.
Group 1: 'contacted' replaced with 'smashed'
Group 2: 'contacted' replaced with 'collided'
Group 3: 'contacted' replaced with 'bumped'
Group 4: 'contacted' replaced with 'hit'
Group 5: 'contacted' remained same
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Imperfect Memories: Misinformation Effect
Depending on wording of question, speed estimates differed.
Group 1: 'smashed'
-
41 m.p.h.
Group 2: 'collided'
-
39 m.p.h.
Group 3: 'bumped'
-
38 m.p.h.
Group 4: 'hit'
-
34 m.p.h.
Group 5: 'contacted'
-
32 m.p.h.
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Imperfect Memories: Misinformation Effect
Week after film – asked; “Did you see the broken glass?”
- Although no broken glass actually shown in film.
Group 1: 'smashed': Majority of subjects given word
'smashed' reported seeing broken glass.
Following initial memory (film) new information ('smashed')
distorted reconstruction of memory (broken glass not in film).
Misinformation Effect caused by information presented
after the memory is formed.
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Imperfect Memories: Existing knowledge
Previous knowledge can also result in mistakes in memory.
Brewer & Treyens (1981).
- Participants told to wait in office for study to begin.
- After 30 seconds, lead to another room and told to write
down everything that had been in the office.
Participants included items such as:
books, filing cabinet, telephone, lamp, pen, pencils, cup.
Even though none of these items in the “office”.
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Forming False Memories
Loftus & Pickrell (1995)
24 subjects given written accounts of 4 childhood events
provided by parent or other older relative.
- 3 events real, 1 event made up.
After reading 4 events, subjects wrote as many details as
could remember about each of the 4 events.
2 weeks later subjects interviewed & asked to remember all
details could about 4 events.
2 weeks after that, subjects again interviewed & asked to
remember all details could about 4 events.
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Forming False Memories
By final interview
6 of 24 subjects
full or partial memories
of false event
(lost in mall at age 5).
Even after debriefing & being informed 'mall incident'
completely fabricated, some participants continued to
struggle with the vividness of the false memory.
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Forming False Memories
Stephen Lindsay (2004)
45 subjects given written accounts of 3 childhood events
that occurred in either 1st or 2nd grade provided by a parent
or other older relative.
- 2 events real, 1 event made up.
½ subjects given picture of their 1st or 2nd grade class.
- No-Picture Group: 23 % developed false memory.
- Picture Group: 65% developed false memory.
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Source Memory
Many people have vivid & substantially accurate memories
of events which are erroneous in the source of the memory.
1980 Presidential Campaign:
Ronald Reagan repeatedly told heartbreaking story of a
World War II bomber pilot who ordered crew to bail out
after his plane seriously damaged by an enemy hit.
Belly gunner wounded so seriously that he was unable
to evacuate the bomber.
Reagan barely held back tears as he uttered pilot's heroic
response: "Never mind. We'll ride it down together."
This story was an almost exact duplicate of a scene in the
1944 film "A Wing and a Prayer."
Reagan had apparently retained the facts but forgotten their
source (Schacter 1996, 287).
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Damaged Memory
• Amnesia
– Loss of memory
• Causes
– Chronic alcoholism (Kosakoff’s syndrome)
– Stroke
– Surgery (e.g. patient HM)
– Bacterial and viral infections (e.g. Clive Wearing)
– Head injury
• Retrograde amnesia = loss of memory for events before injury / illness.
• Anterograde amnesia = loss of memory for events after injury / illness.
The inability to form new memories.
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Failed Memories
Episodic memory can be entirely wiped out by brain damage to the
hippocampal/temporal lobe area.
Clive Waring - famous patient, lost his event memory after an infection of the brain.
He does not remember a moment of his life, before or after the encephalitis.
As soon as information leaves his working memory, it is forgotten, and he always
feels like he is "just waking up" or "just becoming conscious for the first time.“
Clive Waring has disattached knowledge like the fact that England returned Hong
Kong to the Chinese (something that happened after his brain damage).
Clive's problem, being due to brain damage, is irreversible. Most episodes of
dissociative amnesia caused by psychological trauma are reversible.
http://spikedhumor.com/articles/75199/Most_Severe_Case_of_Amne
sia_Ever_Recorded.html?autoplay=true
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Failed Memories
Wilson, B. A., Baddely, A. D., & Kapur, N. (1995). Dense amnesia in a
professional musician following herpes simplex virus encephalitis.
Journal of Clinical and Experimental Neuropsychology, 17, 668-681.
Wilson, B. A., & Wearing, D. (1995). Prisoner of consciousness: A state of
just awakening following herpes simplex encephalitis. In R. Campbell
& M. A. Conway (eds.), _Broken Memories: Case studies in memory
impairment (pp. 14-30). Oxford: Blackwell.
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END
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