Transcript The realm of unknown: implicit knowledge

Cognitive psychology
Rosie IVÁDY
Course schedule
9-10.30 lecture
10.30-10.45 break
10.45- 12.15 lecture
12.15-12.45 lunch break
12.45-13.30 talking seminar
Course requirements
Test on Friday at 9.00
– Multiple choice questions
– True/false questions
Slides can be found on my homepage the day
following class at
www.cogsci.bme.hu/~ivady
Day 1 – Unconscious knowledge, memory and
learning. Evolutionary psychology inborn?
Day 2 – Psycholinguistics, language and thought
Day 3 – Theory of mind and the teleological stance.
Evolution of language and theory of mind
Day 4 – Social and pathological. Religion and mental
health. Morals, taboos, and the Penal Code
The realm of unknown: implicit
knowledge and learning
Budapest Semester in Cognitive
Science
Cognitive Psychology
Day 1.
Memory and learning
Today’s features:
– Memory – conscious and unconscious
– Learning – is there implicit learning?
– Implicit cognition – its social and practical
perspectives
Memory
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
Sensory Memory Store
Divided into two
subtypes:
Sensory
Input
Sensory
Memory
– iconic memory - visual
information
– echoic memory auditory information
Sensory Memory Store
Visual or iconic
memory was
discovered by
Sperling in 1960
It is only conscious in
part – not all of it
Sensitive to eye
movement
Bright background
following it (mask)
Eidetic memory
Around 15% of children
Lasts around 40 seconds
More susceptible to
interference
More likely to create false
memories!
Leads to the question – how
much trace do nonconscious events leave in
normal population?
Subliminal ads
Subliminal is defined in two ways
– Embedded figures of text, not obvious to
superficial examination (picture ads)
– Short exposure times (television or movies)
The question of subliminal
advertisements
Wilson Bryan Key: Subliminal Seduction and
Media Sexploitation
James Vicary - priming
1957 – subliminal advertising
– Eat popcorn
– Drink Coca-Cola
Embedded in a film (0,03s cuts) increased
sales by 20-60%
However he never published this finding
– Later in an interview he claimed that this was a
fabrication
– No one could reproduce it in its original
Critique
Moore: weak effects and strong effects
– Weak effects – over emotions – improbable
because of the competition with various
supraliminal stimuli
– Strong effects – over buyer behaviour –
improbable because of the control over one’s
behaviour
Subliminal advertising is banned in most Englishspeaking countries
Yet many self-help audiotapes containing subliminal
messages are sold
– Self-esteem, weight loss, memory enhancement
even though many studies failed to find evidence that
they work
– mind you: these are double blind studies!
– Also they contain far too long sentences to be processed
linguistically – see priming studies (Greenwald, 1992) –
Brand names?
Placebo
Most companies deny that they use subliminal
ads
– Yet 74% of people believe in it
– 71% of those who believed in it thought it works
as well
Rosenthal effect? (Cassandra-type or selffulfilling prophecy)
New evidence
Revival after 2000 – new studies
Cooper and Cooper (2002)
– Subliminally primed people with pictures of Coca
Cola cans and the word thirsty
– Their self-rated thirst rose
Dijksterhuis et al (2005)
– Subliminally primed drink&cola and neutral words
– Exp group drank more, but no difference is what
Karremans et al (2006)
– Self-rated thirst
– Primed with Lipton Ice or neutral words (Npeic Tol
– same letters) for 23 ms
In pilots they found that usually the prime can not be
guessed – not conscious
– Allegedly, they were supposed to partake in a
detection task
BBBBbBBBBB – how many small bs?
– Choice between Lipton Ice tea (Coke being too
sweet or too popular – brand loyalty) and Spa Rood
Direct emotional priming
Strahan et al. (2005)
– Subliminal priming will only affect people’s
choices if they are goal-relevant
– It affects attitude to bevarages, BUT only if the
person is thirsty! Higher evaluation
Bargh (1996)
– Trait priming – the person is only going to be rude
after the priming, IF (and only if) given the
possibility
Priming studies
Facial expressions
(emotional priming)
– Unconscious effect
– 18-30 ms presentation
– Judged neutral faces
more unpleasant
– Höschel et al. 2001
Memory
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
How do we know STM and LTM
are separate stores?
Amnesia
Sources
Blow to head, Concussion
Korsakoff syndrome (severe vit. B1
deficiency)
Alzheimer’s
Damage to hippocampus, thalamic structures
ECT (electroconvulsive shock therapy)
Midazolam: artifically induced amnesia
Amnesia
Types of amnesia
– Anterograde
– Retrograde
Retrograde amnesia
Temporal gradient:
– early memories are better remembered than memories before
trauma (Ribot’s law)
– Recently formed memories continue to undergo neurological
change: memory consolidation
Retrograde amnesia often becomes less severe over
time
– Most remote memories are likely to return first
Does not affect overlearned information (e.g. skills)
Anterograde Amnesia
Inability to acquire new information
– Think of movie “memento”
– Does not affect short-term memory
– Does not affect general knowledge from the past
– But, it is difficult to learn new facts
– Affects memory regardless of modality (visual,
auditory, tactile, etc). Spares skilled performance
– Hyper-specific memory for those skills that are
learned after onset – learning is expressed only in
Famous Anterograde Amnesiac:
HM
Severe epilepsy, treated with surgery to
bilaterally remove medial temporal lobes,
including hippocampus
Operation 9/1953, 27 years old
Two systems? Dissocition studies:
– STM & LTM tests differ:
Non-word repetition test
Word list learning
Presentation rate
meaningfulness
Hebb : dual trace mechanism
– Cell assembly and
– reverbarating activity – STM
Atkinson & Schiffrin:
– One might consider the short-term store simply as
being a temporary activation of some portion of
the long-term store.
Long-Term Memory
Capacity unlimited
Thought by some to be permanent
Encoding transfers info from STM to LTM –
semantically organized basis
Anterograde amnesia eliminates this – or does it?
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
Spared (implicit) learning in
anterograde amnesia
Claparede study (1911).
– Patient never remembered having met Claparede (doctor)
before
– Claparade offers handshakes with pinprick
– Next time, no explicit memory of event (or doctor)
– Still, patient refuses to shake hands and offers explanation:
“sometimes pins are hidden in people’s hands”
Korsakoff patients & Trivia questions
– Given feedback, then retested. No conscious memory for
items but better performance. “I read about it somewhere”.
(Schacter, Tulving & Wang, 1981).
Famous Anterograde Amnesiac:
HM
Severe epilepsy, treated with surgery to
bilaterally remove medial temporal lobes,
including hippocampus
Operation 9/1953, 27 years old
H.M
General knowledge intact but “stuck in time”.
– Did not learn words introduced after 1953:
“jacuzzi”, “granola”, “flower-child”
Was able to form some memories
– Initially couldn’t learn how to get to his new home.
Took many years to learn his own house
– Could learn to mirror reverse read and mirror trace
HM – Milner’s study (1962)
improvement in H.M. for mirror tracing task (without conscious
recollection of previous training episodes)
 the medial temporal lobes are not necessary for all types of
long-term memory.
Milner, 1965
Learning a new skill: mirrorreverse reading
Amnesics can learn to mirror-reverse read
and are sensitive to repetitions
Implicit and explicit memory
Implicit memory:
past experiences influence perceptions,
thoughts & actions without awareness that any
information from past is accessed
Explicit memory:
conscious access to info from the past
(“I remember that..” )
-> involves conscious recollection
A long story
William James
(1880) Principles
of Psychology
Henri Bergson
(1910)
William Mc
Dougal (1924)
Gilbert Ryle
(1949)
Jerome Bruner
(1950)
Larry Squire
(1988)
Declarative
Memory
Non-Declarative
Habits
Independent
Recollection
Explicit
Bodily Habits.
Recall through action
only.
Implicit
Knowing that
Knowing how
Memory with
record
Declarative
Memory without
record
Procedural
Squire’s model
Representational
Are true or false - verbalizable
Temporal specification
Expressed through performance
rather than recollection
Conversion
Squire argues that
these two are not
clear-cut distinct
systems
– Remember Tulving’s
semantic memory
– Remember source
amnesia!
Children
Confabulation
Dreams
Hypnosis
Amnesia and animals
declarative memory can gradually turn into nondeclarative with repeated exposure
Animal models of the conversion
– Plus shaped maze - rats learn to find food, which was
always west
– Started from the south – then were put into the north
First few trials – turned to west – impaired when lidocaine injected
in hippocampus
Subsequent trials – turned to left (habit, not individual memory) –
impaired when injected with lidocaine in the caudate nucleus
Human learning
Healthy and amnesiacs learn differently
– Exposed to sentences such as „medicine caused
hiccups”
– Had to complement fragments (___ ____ hiccups)
Healthy
– rapid learning
– Semantic mistakes
Amnesiac
– Slow learning
– Faithful to original stimulus
– In non-verbal tasks however (movements) trying
to remember declaratively often impairs
performance!
Competition of strategies
Squire – the two systems often compete to be
the strategy of remembrance – as in healthy
human habit learning tasks in fMRI
– First medial temporal lobe activation
Many mistakes
– Gradually the caudate nucleus takes over
More punctual
– Movements/habits seem to be different from
language
Species dependent strategies
Visual pattern discrimination learning
– (+ vs ->)
– Monkeys with medial temporal lesions learn the task –
slowly
– Amnesiacs seem to learn it very fast, then forget which
answer is correct
– For humans the task is too easy and likely to be taken over
by the declarative system
More accurate would be trying to discriminate
between paintings (original vs forgery)
– This is the same argument as Dijk. Makes!
Modern interpretations
Two most popular are
– Larry Squire – procedural – declarative
Later rephrased non-declaratie and declarative
– Peter Graf, Daniel Schachter – implicit – explicit
They worked with healthy individuals and experimental
settings
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
PANTRY
CARPET
EAGER
CELLO
PRESSURE
LLAMA
ORIOLE
ACRID
Memory Test
Explicit test of memory: recall
– Write down the words you remember from the list in the
earlier slide
Memory Test
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
PACKAGE P*S*E*
*OL*H**
LICORICE
*E*RA
SE*T*O*
C**O*LA*E
*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
Not all implicit memory tests are verbal: Closure Pictures
Implicit memory tests
Priming paradigms:
Subjects presented with target words. Subsequent recognition phase:
Targets and distractors.
•Off-line tasks
Fragment Completion A--a--in
Word Stem Completion
Bri--Implicit memory is evidenced when Ss complete or identify more
studied than non-studied words.
grsfersd
Assassin
Assassin
Ardenisk
•On-line tasks
Perceptual Identification
Lexical Decision
Degraded Word Naming
Implicit memory evidenced by faster RTs for studied words
Gradedness in time
Forgetting: Tulving et al (1982):
S’s learn list of uncommon words (e.g. Toboggan).
Test = standard recognition, fragment completion (_O_O_GA_)
Repetition priming
effect equal for
recognised and non
recognised words
Fragment completion
performance unchanged
after 1w
70
60
50
40
30
Recognition
20
10
Fragment
Completion
0
One hour
One week
Modality shifts
•Jacoby & Dallas (1981)
Targets presented visually at learning, but spoken at test
No effects on recognition memory
Significantly reduced priming effects in implicit test.
•Roediger & Blaxton (1987)
Changed typescript between learning and test:
No effects on recognition memory
Significantly reduced priming effects in implicit test.
Explicit Memory: Sensitive to retention
interval / Dividing attention
Implicit Memory: sensitive to manipulations of
surface features (e.g. modality shifts).
What about amnesiacs in IM tests?
Graf, Squire, & Mandler (1984):
– Study words:
cheese, house, …
– Explicit memory test: cued recall.
Complete fragment to a word from study list:
ch _ _ _ _
– Implicit memory test: word stem completion.
Complete fragment to form any word:
ch _ _ _ _
Word-stem completion spared in
amnesiacs
Graf et al. (1984).
Incidental learning
Graf, Squire & Mandler, (1984)
Presented amnesic patients and controls with word lists - S’s made
pleasantness ratings – no explicit instruction to learn
90
Test stimuli for Cued
Recall and Stem
Completion identical -
80
70
60
50
E.g. BRI--
Amnesics
40
Controls
30
only instructions differed.
20
10
0
Free Recall
Cued Recall
Recog
Stem Completion
Are they different?
1. Stochastic Independence (Sherry & Schacter, 1987)
• If Implicit and Explicit memory effects represent the function of separable
memory systems, there should be no correlations between measures of Implicit
and Explicit memory.
• Tulving et al: (1982) There is no correlation between recognition
and fragment completion.
1. Validity condition
• If implicit memory is one system then there ought to be
correlations between different measures of that systems
performance.
• BUT: No correlations - so lots of different implicit memory
systems?
• Partly this is the reason of the multiple subsets of Squire’s nondeclarative model (and the reason he renamed it from procedural)
•System accounts - favoured by neuropsychologists observing
preserved abilities in amnesics
•Tulving & Schacter (1994) - Differences in implicit / explicit
memory reflect the operation of separate memory systems.
•Process accounts - favoured by experimental psychologists
working healthy subjects (often using priming paradigms)
Roediger (1990)
Distinction between Implicit / Explicit memory is confounded by
distinction between the processes required to perform these tests.
•Explicit tests - conceptual information
•Implicit tests - require “data-driven” processes that operate on more
perceptual level.
Critique of healthy subjects
Two criteria
– Unintentional retrieval strategy
The instruction must be : complete it with the first word that comes
to your mind
– Not accompanied by conscious recollection
They do not find out in the middle of the experiment that the
studied lists and „independent tasks are related”
– The first one is always true, but the second is dubious
– Butler: as few studies meet both, the two systems – at least
basen on healthy individuals – might not be separate
– Squire – this is ignoring accumulated neuropsychological
knowledge
Strategies to deal with this
Retrieval intentionality criterion
– Instructions
Chance recognition
– Implicit task performance is better than the explicit one –
therefore there is some unconscious information
Awareness questionnaires
– Inability to recall the true nature of the mental state at test
later
On-line awareness analysis
– First word that comes to your mind BUT NOT the one on
the list
– False negatives – if completed with a different word – is it
conscious recollection or simply lack of even implicit
memory?
Dissociation
Major symptoms (Steinberg, 1997)
1. Amnesia – holes of memory
1. Few days to several years
2.
3.
4.
5.
Depersonalization – detached from oneself- alien
Derealization – surroundings are unreal
Identity Confusion – unnoticeable to environment
Indentity Alteration – can be noticed
Linked to early childhood trauma – usually sexual abuse
– Explanation – because of the harassment the body is no longer
percieved as a safe home – escaping is only possible in the mind
– Sexual abuse – causes DID in 80% of cases
??? In Hungary there are hardly any – supposedly 1% should be
Post-traumatic stress disorder is very rarely detected
Dissociative Identity Dosirder
DID: Dissociative Identity Disorder (DSM-IV)
•Key symptom is “inter-identity amnesia” - One identity claims
amnesia for events experienced by other identities.
Rafaele et al (2002): Tested 31 DID patients on 3 implicit memory tests.
Also tested 25 controls and 25 DID “simulators”
Material learned as one personality and tested as another
Equal implicit memory effects in all three groups for both data driven and
conceptually driven implicit memory tasks.
“What we did find in both our implicit and explicit memory studies was a
dissociation between objective memory performance and patients’
subjective reports: that is, although patients indicated no subjective
recollection of the encoding phase performed by a different identity states
at all, their test scores indicated normal memory functioning”
Thus (according to Rafaele et al) - DID patients suffer from a lack of
“memory meta-awareness”.
Transitory amnesia
Psychogenic amnesia
– Following a traumatic event, complete loss of
memory for a few days
– The case of M.F.
– he was at the Gare de l’Est for 5 days – was going to go on
Tuesday, but suddenly discovered that on the train ticket he
bougt Saturday was printed.
– After his divorce and suicidal thoughts he lived in his car –
which provided him with protection and body
– Too embarassed to confess he’s unemployed, he lies
constantly to his new partner
Lack of consciousness
Coma, vegetative state and
locked-in syndrome
Disorders of consciousness
Vegetative State
Minimally conscious state
Locked-in syndrome
Often no motor responses
Arousal – opening of eyes, reaction to immediate
stimuli
Awareness of environment and self
– Awareness of the self versus the other
Vegetative state
Patients seem to be awake – but there is no indication of
will, voluntary action.
Wakefulness is present, but awareness is not
Terri Schiavo – judicial murder?
What is death?
– Brain death
– Devastation of neocortex
Permanent cessation of ‘‘those higher functions of the nervous system
that demarcate man from the lower primates
Permanent (after 3-12 months)
Some Alzheimer’s diseases, anencephalic neonates
Minimally Conscious State
The border between VS and MCS is blurred
inconsistent, erratic responsiveness
Non-reflex bahaviour
– To qualify, they have to show clearly discernible
evidence of consciousness
Following simple commands consistently (3/4!!)
Yes/no answers – regardless of accuracy
Intelligible verbalization
Purposeful behaviour (reaction to own name)
Locked-in syndrome
(maladie de l'emmuré vivant, Eingeschlossensein)
Damage to the ventral part of the midbrain (pons) – a
trajectory to muscle movements
Patients are fully aware of their environment, but are
unable to move
– They can move their extraorbital muscles – basically the eyes
– and sometimes face muscles
Can communicate using dasher and eye tracking
– Jean-Dominique Bauby
Comatose patients
Anoxic coma – very little chance to wake up
Traumatic coma- better prognostics
Stroke How do you know if you should switch the
machine off?
Those who do not start to wake up after 2-4
weeks have very bad prognosis
Glasgow Coma Scale
1.
2.
3.
4.
Best eye response (E)
There are 4 grades starting with the most severe:
No eye opening
Eye opening in response to pain. (Patient responds to pressure
on the patient’s fingernail bed; if this does not elicit a
response, supraorbital and sternal pressure or rub may be
used.)
Eye opening to speech. (Not to be confused with an awaking
of a sleeping person; such patients receive a score of 4, not 3.)
Eyes opening spontaneously
Glasgow Coma Scale
1.
2.
3.
4.
5.
Best verbal response (V)
There are 5 grades starting with the most severe:
No verbal response
Incomprehensible sounds. (Moaning but no words.)
Inappropriate words. (Random or exclamatory articulated
speech, but no conversational exchange)
Confused. (The patient responds to questions coherently but
there is some disorientation and confusion.)
Oriented. (Patient responds coherently and appropriately to
questions such as the patient’s name and age, where they are
and why, the year, month, etc.)
Glasgow Coma Scale
1.
2.
3.
4.
5.
6.
Best motor response (M)
There are 6 grades starting with the most severe:
No motor response
Extension to pain (adduction of arm, internal rotation of shoulder,
pronation of forearm, extension of wrist, decerebrate response)
Abnormal flexion to pain (adduction of arm, internal rotation of
shoulder, pronation of forearm, flexion of wrist, decorticate response)
Flexion/Withdrawal to pain (flexion of elbow, supination of forearm,
flexion of wrist when supra-orbital pressure applied ; pulls part of body
away when nailbed pinched)
Localizes to pain. (Purposeful movements towards painful stimuli; e.g.,
hand crosses mid-line and gets above clavicle when supra-orbital
pressure applied.)
Obeys commands. (The patient does simple things as asked.)
Clinical diagnosis
How to decide on coma
Brain responses
– active and passive odball paradigm
– Mismatch negativity (MMN) – novelty of stimulus
-150-250 ms onset
– P300 ellicited by infrequent stimuli
Called P3a if it is task irrelevant stimuli
– Tone-evoked usually
Self-referential stimuli
Own-name effect – coctail party effect in
– dichotic listening tasks
– RSVP - No attentional blink for own name, but a
significant attentional blink for the stimulus after
– Slows judgements – such as two digits having the
same parity - considerably
Comatose patients
Subjects own name (SON) – ellicits
involuntary orientation, attention and P300
Deviant tones – probability of 0,14 (other
tones)
Novel tones – probability of 0,03 (own name)
P300 to own name
The combination of P300 and MMN is the best
predictor of awakening from coma
The predictions are somewhat more reliable in
anoxic coma cases
P300 – an interesting story
Difficult: diurnal and age-related changes
Schizophrenia – reduced P300 component
– Impaired controlled information processing
Hypnosis : altered consciousness
Alcoholics also show decreased P300 – not clear if it
is addiction or alcohol itself
LIE DETECTION – Brain fingerprinting in
MERMER by Lawrence Farwell
– "Memory and Encoding Related Multifaceted
Electroencephalographic Response"
Brain Fingerprinting
Known and relevant events produce a different P300
than unknown and irrelevant ones (remember the
odball)
information present/absent judgement
– Details of a crime unknown but to the culprit presented – if
there are none, not applicable…
– Can be applied to alibi defense as well (time!)
– Pictures, words, phrases
6-10 crime-related, 6-10 life-related (related basline)
and 12-20 irrelevant stimuli (unrelated baseline)
Accuracy is reported to be over 99%
Admissible in US court
Harrington v. State, Case No. PCCV 073247.