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Memory
Outline
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•
•
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Introduction to memory
Memory components
Memory processes
False memories
Introduction to
Memory
Introduction to
Memory
• Take out a sheet of paper
• I will ask you a question
• Write down, in order, all responses
that come to mind
• Ready?
Introduction to Memory: Summary
• Research on memory examines factors
that influence encoding, storage &
retrieval
• Tip-of-the-tongue phenomenon
• Memory organized by sound, letter, or
meaning
• Discussion-cued & list-cued
• Recall vs. recognition
• Short term vs. long term
Memory
Components
Memory Components: Outline
• Sensory Memory
• Working Memory
• Short Term
Memory
• Long Term
Memory
Components: Sensory Memory
Sensory Memory: Brief memory of sensory
information
• Length: Up to 1 second
• Capacity: About 12 pieces of information
• Iconic Memory: Visual stimuli
(fleeting picture image)
• Echoic Memory: Auditory stimuli
Components: Working Memory
Working Memory
• Length: As long as you can hold your
attention
• Remember these letters…
(3)
(4)
(5)
(6)
B F G
T L A D R E H J K PLWORS
(7) A X F L U M Y
(8) E O G K P Z I G
(9) L U S I W F K A O
Components: Working Memory
Working Memory
• Length: As long as you can hold your
attention
• Remember these letters…
(3)
(4)
(5)
(6)
B F G
T L A D R E H J K PLWORS
(7) A X F L U M Y
(8) E O G K P Z I G
(9) L U S I W F K A O
Components: Working Memory
Working Memory
• Length: As long as you can hold your
attention
• Remember these letters…
• Capacity: about 7 pieces of information
• Rehearsal of information
• Association of new information with
existing memories
Components: Short & Long Term Memory
• Short Term Memory (STM)
– Length: 30 seconds
– Capacity: 7 pieces of information
– Quickly forgotten unless rehearsed and
transferred into LTM
• Long Term Memory (LTM)
– Length: Indefinite
– Capacity: Billions of pieces of information
Memory Components:
Summary
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•
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Sensory Memory: Iconic & Echoic
Working Memory
Short Term Memory
Long Term Memory
Memory Processes
Memory Processes
• Encoding
– Processing of information
• Storage
– Retention of encoded
information
• Retrieval
– Accessing stored information
• Forgetting
– Memory failure
Memory Encoding
Memory Encoding - Outline
• Introduction to encoding
• Routes to encoding (automatic &
effortful)
• Influences on encoding
Memory Encoding
Encoding: The process of getting
information into memory
• Biological version of data entry
• Multiple routes:
– Automatic
– Effortful
Encoding: Automatic Route
Automatic Processing: Automatic,
unconscious processing of
incidental info
– Time (ex. sequence of events, time of
day)
– Frequency (ex. times encountered)
– Space (ex. place on the page)
• Automatic processing can be
learned
– Ex. Writing, driving, reading music
Encoding: Effortful Route
• Effortful Processing: Processing of
information that requires conscious
effort and attention
• How do we process with effort?
• Rehearsal: Conscious repetition of
information
– Maintains information in working memory
– Provides more time for encoding to occur
Encoding: Ebbinghaus
• Hermann Ebbinghaus
– Learn nonsense syllables (TUV ZOF GEK
WAV)
JIH
BAZ
FUB
YOX
SUJ
XIR
DAX
LEQ
VUM
PID
KEL
WAV
TUV
ZOF
GEK
HIW
Encoding: Ebbinghaus
• Hermann Ebbinghaus
– Learn nonsense syllables (TUV ZOF GEK
WAV)
• Rehearsed on day 1 until perfect recall
– Tested and Re-rehearsed on day 2 until
perfect recall
– Tried many variants with timing, repetitions,
etc.
Encoding: Ebbinghaus
Time
20
in
minute
s
15
taken
to
relearn 10
list on
day 2
5
08
16
24
32
42
53
64
Number of repetitions of list on
day 1
Encoding summary so far…
• Introduction to encoding
• Routes to encoding (automatic &
effortful)
– Importance of rehearsal
• Influences on encoding
– Serial Position Effect
– Meaning
– Mental Imagery
– Spacing Effect
Encoding Influences: Serial
Position
• Serial position: Where the information is
located within a grouping
Write down as many U.S. presidents as you
can in 1 minute… GO!
Encoding Influences: Serial Position
• Serial position: Where the information is
located within a grouping
• Serial Position Effect: Tendency to
remember the first and last items in a list
– Primacy Effect: Tendency to recall first things
in list
(strongest with LTM)
– Recency Effect: Tendency to recall last things
in list
(strongest with STM)
Encoding Influences: Serial
Position
Percentag
e of
words
recalled
90
80
70
60
50
40
30
20
10
0
1 2 3 4 5 6 7 8 9 10 11 12
Position of word
in list
Encoding Influences:
Meaning
Meaning
• We encode the meaning of words, not the
actual words
• The more meaningful the word, the easier to
encode
– 10x easier than nonsense words
• How do we make things meaningful?
– Relating to self
– Relating to other information already learned
– Depth of processing
Encoding Influences: Mental Imagery
Mental Imagery
• Powerful aid to effortful
processing
• Remember words that can be
pictured better than abstract, lowimagery words
• Best if can associate image and
meaning
Ex. “fire” vs.
“process”
Ex. “dog” vs.
“happy”
Memory: Outline
• Introduction to memory
• Memory components: Sensory Memory,
Working Memory, STM, LTM
• Memory processes
– Encoding
– Storage
– Retrieval
– Forgetting
• False memories
Encoding Influences: Spacing
Effect
• Spacing Effect: Retain info
more easily if we practice
it repeatedly than if we
practice it in one long
session
• Implications for
“cramming”?
Encoding Influences: Chunking
Chunking: Organizing items into
manageable units
1-7-7-6-1-4-9-2-1-8-1-2-1-9-4-1
Write them down
1776 1492 1812 1941
• Ex. Acronyms (e.g., Roy G Biv)
Encoding – Emotion/Stress
The role of emotion/stress in memory
• Which are stronger emotional
memories or neutral memories?
• Amygdala boosts activity in memory
forming area
– Experiencing vs. hearing about
• Works better with short term emotion/
stress than long term
– Earthquake vs. Sustained Abuse
Encoding: Summary
• Introduction to encoding
• Routes to encoding (automatic &
effortful)
• Importance of rehearsal in encoding
• Influences on encoding
– Serial Position Effect
– Meaning
– Mental Imagery
– Spacing Effect
– Chunking
Memory Storage
Memory Storage: Outline
• Memory storage capacity and contents
• What information is stored?
• How is memory stored?
Memory Storage: Capacity
Is the brain’s storage capacity limited?
• Yes: from a literal standpoint
– Most adults store impressive amounts of info
(e.g., 1 billion bytes or 1,000,000,000)
– Capacity: 100 trillion bytes (or 100 terabytes)
• No: from a practical standpoint
Storage: What
information is stored?
• Only the most important details
Storage: What information is stored?
• Implicit Memory
– Memory of procedures and
skills
– “Non-declarative:”
Independent of consciousness
– Ex. If Clive sits at a piano, he
can play
• Explicit Memory
– Memory of facts and
experiences
– “Declarative:” Consciously
known
– Ex. If asked “can you play the
piano,” Clive may say no
Storage: How is memory stored?
• Memory is stored as synaptic changes
and neural pathways
– Learning creates and changes neural
synapses
– Specific sequences of neural activation
create stored memories
– Retrieval = activating correct
neurons in the correct order
– The more we access the
memory, the stronger the
neural pathways become
Memory Storage: Summary
• Is the brain’s storage capacity limited?
- No
• What information gets stored?
– Only important information
– Implicit and explicit memories
• How is memory stored?
– Synaptic changes and
neural pathways
Memory Retrieval
Memory Retrieval: Outline
• Recall & Recognition
• Context Effects
Memory Retrieval
 Recall: Measure of memory in which the
person must retrieve information
learned earlier
 Ex. Fill-in-the blank test
 Recognition: Measure of memory in
which the person has only to identify
items previously learned
 Ex. Multiple-choice test
Memory Retrieval: Context Effects
• Context Effects: Remembering will be
better if the cues present at encoding are
also present at retrieval (i.e., if the
“context” matches)
• Context Examples
– Music
– Temperature
– Time of day
– Kinesthetic sense
• Godden & Baddley (1975)
– Scuba Divers Experiment
Memory Retrieval: Context Effects
(Godden & Baddeley,
1975)
Percentage of
words
recalled
40
30
20
10
0 Water/
land
Land/
water
Different contexts for
hearing and recall
Water/
water
Land/
land
Same contexts for
hearing and recall
Memory Retrieval: Context Effects
 Mood-congruent Memory: Tendency to
recall experiences that match one’s
current mood
 Emotions or moods serve as retrieval cues
 State-dependent Memory: Tendency to
recall information best when in the same
physiological state as when the
information was learned
 Ex. Happy, drunk, depressed
Memory Retrieval: Summary
• Recall & Recognition
• Context Effects
– Godden & Badley (1975)
– State-Dependent Memory
– Mood-Dependent Memory
Forgetting
Forgetting: Outline
• Ebbinghaus’s “Forgetting Curve”
• Forgetting as memory failure
– Encoding failure
– Retrieval failure
– Interference
• Amnesia
Forgetting: Ebbinghaus’ Curve
 Ebbinghaus’ “forgetting curve”
 Loss initially rapid, then levels off with time
Percentage of
60
list retained
50
when
relearning 40
30
20
10
0
12345 10 15 20 25 30
Time in days since learning list
Forgetting: Ebbinghaus’ Curve
The forgetting curve for Spanish learned
in school
100%
Percentage
of
original
vocabulary
retained
90
80
70
60
50
Retention
drops,
then levels off
40
30
20
10
0
1 3 5
9½
14½
25
35½
49½
Time in years after completion of Spanish course
Forgetting as Memory Failure
• Forgetting
can occur
at any
memory
stage
Forgetting: Encoding Error
Forgetting as encoding failure
 Error = Information never enters LTM
Attention
External
events
Sensory
memory
Encoding
Short- Encoding
term
memory
Encoding
failure leads
to forgetting
Longterm
memory
Forgetting: Retrieval Error
Forgetting as retrieval failure
 Error = Information enter LTM but
cannot be retrieved from LTM
Attention
External
events
Encoding
Sensory
Short-term
memory Encoding memory
Retrieval
Long-term
memory
Retrieval failure
leads to forgetting
Forgetting: Interference
 Learning may disrupt retrieval of other
info
 Proactive Interference (forward acting)
 Disruptive effect of old learning on recall
of new information
 Ex. List 1 interferes
Old
New
with recall of List 2
 Retroactive Interference (backwards
acting)
 Disruptive effect of new learning on recall
of old information
 Ex. List 2 interferes
Old
New
with recall of List 1
Forgetting: Retroactive
Interference
Percentage 90%
of syllables
recalled 80
Without interfering
events, recall is
After sleep
better
70
60
50
40
30
20
10
0
After remaining awake
1
2
3
7
4
8
5
Hours elapsed after learning syllables
6
Forgetting: Brain Insult
• Amnesia: loss of memory
– Hippocampus: involved in transfer of
explicit memories into long-term memory
– Cerebellum: involved in transfer of
implicit memories
• Case of Clive Wearing
Forgetting: Brain Insult
• Clive video
Clive Wearing
(1938 - )
Forgetting: Summary
• Ebbinhaus’s “Forgetting
Curve”
• Forgetting as memory
failure
– Encoding failure
– Retrieval failure
– Interference
• Proactive & Retroactive
Interference
• Amnesia
– Clive Wearing
False Memories
False Memories: Outline
• Research on false memories
– Eyewitness testimony
• Misinformation effect
• Source amnesia
False Memories
Creating false memories through
research
• Elizabeth Loftus’ studies of being lost in
a store
• Week Later: ≈ 35% reported being lost
False Memories: Eyewitness
Testimony
Depiction of actual
accident
Leading question:
• Car crash study
• Implication:
Eyewitnesses
reconstruct
memories when
questioned
“About how fast were the cars
going when they smashed into
each other?”
Memory
construction
False Memories: Eyewitness
Testimony
• Memories are constructed: we filter
information and fill in missing pieces
Memory: Summary
•
•
•
•
Introduction to memory
Memory components
Memory processes
False memories
False Memories
 Memories are constructed: we filter
information and fill in missing pieces
 Misinformation Effect
 Incorporating misleading information into
one's memory of an event
 Source Amnesia
 Attributing the wrong source to an event
that we experienced, heard about, read
about, or imagined (misattribution)
False Memory
• Repressed & Recovered Memories
– Childhood sexual & physical abuse
• Preschool children are sensitive to
suggestion and score much higher on
scales of imagination
– Can be induced to report false events with
suggestive interviewing techniques (along with
older children)
– Are also able to recall event accurately with less
suggestive, more effective techniques
Memory Construction
 Most people can agree on the following:
Injustice happens
Incest and sexual abuse happens
Forgetting happens
Recovered memories are commonplace
Memories recovered under hypnosis or drugs are
especially unreliable
 Memories of things happening before age 3 are
unreliable
 Memories, whether false or real, are upsetting
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False Memories:
Summary
• Research on false memories
– Eyewitness testimony
• Misinformation effect
• Source amnesia