Transcript Memory - University of California, Irvine

Overview of Memory
Research
Modal Memory Model
Basic Distinctions
• STM
– short term memory
• limited capacity
• limited duration
• holding available recent and relevant information in
a temporary store
• LTM
– long term memory
• unlimited storage
• relatively permanent
• store for episodic and semantic memory
Modal Model of Memory
(Atkinson & Shiffrin, 1968)
Short-term memory
is a limited capacity
store for information
-- place to rehearse
new information
from sensory buffers
Items need to be
rehearsed in shortterm memory before
entering long-term
memory
Probability of
encoding in LTM
directly related to
time in STM
a memory test...
DOORKNOB
CONCRETE
SUNSHINE
SOFTBALL
RAILROAD
HAMMER
CURTAIN
DOCTOR
SUBWAY
CANDLE
COFFEE
FOLDER
TURKEY
PLAYER
LETTER
PENCIL
KITTEN
TOWEL
MAPLE
TABLE
Serial Position Effects
no
distractor
task
distractor
task
• In free recall, more items are recalled from start of list
(primacy effect) and end of the list (recency effect)
• Distractor task (e.g. counting) after last item removes recency
effect
Serial Position Effects
• Explanation from Modal Memory Model:
– Early items can be rehearsed more often
 more likely to be transferred to long-term memory
– Last items of list are still in short-term memory (with no distractor task)
 they can be read out easily from short-term memory
Encoding & Retrieval Effects
Levels of Processing
(Craik & Lockhart, 1972)
Modal Memory Model  time in rehearsal buffer determines memory
strength
Levels of processing effect:
The way information is processed affects recall. Deeper levels of
processing (e.g., emphasizing meaning)
leads to better recall  encoding effect
Encoding Specificity Principle
• Recollection performance depends upon the interaction
between the properties of the encoded event and the
properties of the retrieval information
• Example:
– context dependent effects: information learned in a
particular context is better recalled if recall takes
place in the same context
Godden & Baddeley (1975)
Memory experiment with deep-sea divers
– Deep-sea divers learned words either on land or underwater
– They then recalled the words either on land or underwater
Mood Congruence
• Easier to remember
happy memories in a
happy state and sad
memories in a sad
state.
• Teasdale & Russell
(1983): subjects study
positive or negative
words in normal state.
Test in positive or
negative induced
states.
 mood primes certain
memory contents
State-dependent recall
• Does physical state matter?
• Eich et al. (1975): study while smoking normal or
marijuana cigarette. Test words under same or different
physical condition
Spacing effects
• Memory is better for repeated
information if repetitions occur
spaced over time than if they
occur massed, one after
another.
• Experiment: study 48 words, 24
of which are repeated. Spacing
interval varied from 1,2,4,8,20
to 40 presentations.
• Results: better memory for
items with greater spacing.
• Explanation based on encoding
specificity principle: spaced
items can be encoded in
multiple ways  more likely to
be retrieved
Melton & Schulman, 1970
Working Memory
Views on Short-Term memory
• Miller’s memory span (7 ± 2 discrete slots)
• Short-term memory = activated long-term
memory
• Baddeley’s theory of working memory
– Set of slave systems rehearsing and “working” on
information
• Working memory capacity
– Measures focus of attention with distracting tasks
Baddeley’s working memory theory
• Concept of working memory: brief, immediate memory of
material we are currently processing
• Working memory is not a passive store-house such as
short-term memory – it is more like a work bench where
material is constantly handled, combined and
transformed
Visuo-spatial
sketchpad
Phonological
Loop
Central
Executive
Long-term
memory
Phonological Loop
(a.k.a. articulatory loop)
• Stores a limited number of sounds – number of words is
limited by pronunciation time, not number of items
• Experiment:
– List 1: “Burma, Greece, Tibet, Iceland, Malta, Laos”
– List 2: “Switzerland, Nicaragua, Afghanistan,
Venezuela, Philippines, Madagascar”
– Typical results:
list 1  4.2 words
list 2  2.8 words
Phonological Similarity
• Note: most
working memory
tasks involve
serial recall
man
mad
cap
can
map
(Baddeley, 1966)
pen
rig
day
bar
cup
big
huge
broad
long
tall
old
late
thin
wet
hot
• Short-term
memory worse for
phonologically
similar items 
interference in
phonological loop
Reading rate determines serial recall
• Baddeley (1986) tested recall
for five words varying from 1
to 5 syllables.
– 1 syllable:
wit, sum, harm, bay, top
– 5 syllables:
university, opportunity,
aluminum, constitutional,
auditorium
• Reading rate seems to
determine recall performance
• Phonological loop stores 1.5 2 seconds worth of words
Working memory and Language Differences
• Different languages have
different #syllables per
digit
• Therefore, recall for
numbers should be
different across
languages
• E.g. memory for English
number sequences is
better than than Spanish
or Arabic sequences
(Naveh-Benjamin & Ayres, 1986)
Problems with Baddeley’s theory
• Pronunciation time does not always predict
recall very well
Problems with Baddeley’s theory
• Even with long delays, memory span does not decrease
much
• Underspecified processes and representation
– Serial recall requires memory for the order of items 
how is order information stored?
– How does central executive work?
– How does interference in phonological loop work?
Long-Term Memory Systems
Are there multiple LTM memory systems?
• How do you learn a new skill?
• How do you learn a new fact?
• How about learning about an event?
• Is there one long-term memory (LTM) system for these
types of knowledge or are there multiple LTM systems?
Squire’s Taxonomy of memory
MEMORY
EXPLICIT
SEMANTIC
(facts)
EPISODIC
(events)
IMPLICIT
PRIMING
(perceptual,
semantic)
PROCEDURAL
(skills)
Implicit and explicit memory
• Implicit memory:
past experiences influence perceptions, thoughts &
actions without awareness that any info from past is
accessed
• Explicit memory:
conscious access to info from the past
(“I remember that..” )
-> involves conscious recollection
-> term often used synonymously with episodic
memory
Explicit & Implicit MEMORY TESTS
Look at the following words. I will test your
memory for these words in various ways.
SPONGE
CANDY
DOLPHIN
PACKAGE
POSTER
LICORICE
ZEBRA
SECTION
CAMOFLAGE
MISTAKE
PORTAL
KNAPSACK
COFFEE
QUAIL
ALPINE
HANDLE
PANTRYCARPET
EAGER
CELLO
PRESSURE
LLAMA
ORIOLE
ACRID
EXPLICIT TEST OF MEMORY: RECALL
WRITE DOWN THE WORDS YOU REMEMBER FROM THE LIST IN
THE EARLIER SLIDE
IMPLICIT TEST OF MEMORY: WORD FRAGMENTS
ON THE NEXT SLIDE, YOU WILL SEE SOME WORDS MISSING
LETTERS, SOME “WORD FRAGMENTS” AND SOME ANAGRAMS.
GUESS WHAT EACH WORD MIGHT BE.
EGNOPS
*AN*Y
*OL*H**
PACKAGE
P*S*E*
LICORICE
*E*RA
SE*T*O*
*I*TA*E
PORTAL
KNAPSACK
COFFEE
*U*IL
AEILNP
*AN*LE
*A*T*Y
ACEPRT
*A*E*
C*L**
*RE*S**E
AALLM
EILOOR
*C*ID
C**O*LA*E
Implicit Memory Tasks
• Word-fragment completion is an implicit memory task.
Fragments are (often) completed with words previously
studied in the absence of an explicit instruction to
remember the word
• Amnesiacs often showed spaired implicit memory 
dissociation suggest different systems for implicit and
explicit memory systems
HM: Amnesic
• Severe epilepsy, treated with surgery to
bilaterally remove medial temporal lobes,
including hippocampus
• Operation 9/1953, 27 years old
HIPPOCAMPUS
MEDIAL TEMPORAL LOBES
HM: Amnesic
Operation 9/1953, 27 years old
• Tested 4/1955, age 29
– Reported date as 3/1953, age of 27
– No memories since operation
– IQ better than pre-op (112)
– Fewer seizures
HM: Amnesic
• Profound failure to create new memories
– Can’t find new home (after 10 mos.)
– Can’t remember new people, names, tasks
– Events/People since operation
– Language essentially frozen in 50’s
– Exceptions: Ayatollah, rock ‘n roll
HM: Amnesic
• Mirror tracing task, Milner, 1965
HM: Amnesic
Mirror tracing task, Milner, 1965
• improvement in H.M.
• no conscious recollection of previous training episodes
HM: Stem-completion
Graf et al. (1984):
Study: word list (table, garden,umbrella)
Test:
- free recall
- cued recall: complete word stem with word from
study list
umb____ ??
- word stem completion: complete word stem with
first word that comes to mind
gar___??
HM: Stem-Completion
Free
Recall
Cued Completion
Recall
HM: No memory for studying of list
Learning to Miror-Reverse Read
Amnesics can learn to mirror-reverse
read and are sensitive to repetitions
Spared implicit memory in anterograde amnesia
• Claparede study (1911).
– Patient never remembered having met Claparede
(doctor) before
– Claparade offers handshake with pin hidden in his
hand
– Next time, patient has no explicit memory of painful
event (or doctor)
– Still, patient refuses to shake hands and offers
explanation: “sometimes pins are hidden in people’s
hands”
Implicit/ Explicit Memory with Normals
• Jacoby (1983)
• Study conditions:
– generate: give antonym to
– context:
study word in context
– no context:
hot - ...
hot - COLD
... - COLD
• At test:
– Explicit memory test: recognition memory
– Implicit Memory test: Speed up on perceptual
identification test: how much faster can you identify a
word flashed 40ms on screen when you have studied
word before?
Results
Knowledge & Memory
How well do people recall events?
•
Memory is not just reproductive
– We do not recall the original event exactly
•
Memory for events is often reconstructive
– We construct a memory by combining elements
from the event with our existing knowledge.
What does a penny look like?
Memory for Details vs. Gist
• Memory is better for meaningful, significant features than
for details of language or perception, suggesting that we
have knowledge representations based on our
interpretations of meaning.
• Representation for meaning
– Propositional representations
– Semantic Networks
– Schemas
– Scripts
– Latent Semantic Analysis (LSA)
Evidence for Schema’s
A simple demonstration experiment
I am going to show you a picture of a graduate student’s
office. Just take a look at it for a while
Now write down all the things you can remember
Potential responses:
Chairs
Desk
Table
Boxes
Bottle of wine
Picnic basket
Books
Skull
Brewer & Treyens (1981): 30% of subjects (falsely)
recalled that books were present
Story Retelling involves Schemas
• Bartlett (1932) told a native American story “war of the
ghosts” to one subject
• This subject tells story to the next subject, and so on
(method of serial reproduction)
• What happens during retelling of story from memory?
War of the Ghosts
[excerpt] One night two young men from Egulac went down to
the river to hunt seals and while they were there it became
foggy and calm. Then they heard war-cries, and they thought:
"Maybe this is a war-party". They escaped to the shore, and hid
behind a log. Now canoes came up, and they heard the noise
of paddles, and saw one canoe coming up to them. There were
five men in the canoe, and they said: ....
Typical Results
•
•
•
Gist remains intact -- the main plot and sequence of
events
Omission Errors
– Quite a bit of material is omitted (e.g. the name
Egulac) and minor events
Normalization Errors
– Additional info was added to make the story more
coherent
– As Ss recalled/retold the story more and more, it
tended to warp over time.
Memory for Event Sequences
1.
2.
3.
John was hungry
He went into a restaurant and ordered a sandwich
He paid his bill and left
Question: Did John eat his sandwich? From whom did
he order a sandwich? What was the bill for?
None of the answers is stated in the sentences but are
based on inferences
Scripts
• Inferences are based on representations for stereotyped
sequences of actions  scripts
• A restaurant script:
Evidence for Scripts
• Bower et al. (1979)
• Ss. study a sequence of events
• when an event is out of order, Ss might correct the order to
the stereotypical order
E.g., restaurant story where bill is paid first is
remembered in correct order (bill is paid last)
• Some events are (incorrectly) filled in based on inference
• Suggests: Events encoded with respect to general script
Schemas & Scripts: Implications
• Information from specific events is combined with
general knowledge
– Experience shapes scripts
– Scripts guide recall
• Advantages & Disadvantages