Download The realm of unknown: implicit knowledge

Some provocative questions
Does natural selection still work in our
highly artificial society?
What will the homo sapiens be like in
another 200.000 years?
(Why are there mental illnesses, if
adaptationism is so powerful in
evolutionary psychology?)
Freud, Sigmund
What do Freud and Evolutionary
psychology have in common?
– The Unconscious
The realm of unknown: implicit
knowledge and learning
Budapest Semester in Cognitive
Science
Cognitive Psychology
Day 2.
But before anything else
Provo is a picturesque region of France.
Corman was a pretender to the throne of
Provo.
He was tired of waiting.
He thought arsenic might work.
Try to remember these!
Look at these pictures
Now look carefully at these
pictures. You will need to
recall them later.
Memory
How come?
The Atkinson-Schifrin-model
•Malfunctions
•Experimental data
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
Famous Anterograde Amnesiac:
HM
Severe epilepsy, treated with surgery to
bilaterally remove medial temporal lobes,
including hippocampus
Operation 9/1953, 27 years old
Anterograde Amnesia
Inability to acquire new information
– “Memento”
– Does not affect short-term memory and general
knowledge from the past
– It is difficult to learn new facts
– Affects memory regardless of modality (visual,
auditory, tactile, etc). Spares skilled performance
Try to recall as many items as you
can!
Cat
Apple
Banana
Hammer
Toothpick
Parrot
Table
Blackberry
Fly
Chair
Screw
Pigeon
Orange
Knife
Bed
Dog
Fork
Rat
Primacy effect
Recency effect
Peterson’s STM Task
Test of memory for
3-letter nonsense
syllables
Participants count
backwards for a
few seconds, then
recall
Without rehearsal,
memory fades
Voices of dissent - again
Two systems? Dissocition studies:
– STM & LTM tests differ:
Non-word repetition test
Word list learning
Presentation rate
Meaningfulness
– Can there be a clear division line?
Is there an alternative path – crossing out
STM entirely?
Memory
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
Memory
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
There is more than we can
tell…
Eidetic pictures of
children
How many stripes did you
see on the cat?
Sensory Memory Store
Function - holds
information long enough to
be processed for basic
physical characteristics
Capacity - large
Sensory
Input
Sensory
Memory
– can hold many items at
once
Duration - very brief
retention of images
– .3 sec for visual info
– 2 sec for auditory info
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)
Sperling’s Experiment
Presented matrix of letters
for 1/20 seconds
Report as many letters as
possible
Subjects recall only half of
the letters
Was this because subjects
didn’t have enough time to
view the entire matrix? No
Sperling’s Experiment
Sperling showed people
can see and recall ALL the
letters momentarily
Sounded low, medium or
high tone immediately after
matrix disappeared
High
Medium
Low
– tone signaled 1 row to report
– recall was almost perfect
 Memory for image fades after
1/3 seconds or so, making report
of entire display hard to do
Sperling’s Iconic Memory
Experiment
G
A
V
M K
U
X
L
S
F
Q
J
O
N
U
A
N
Z
Is the fading effect evolutionarily adaptive?
– Would we not be better off like Funes, the
famous rememberer of Borges’ short story?
Theories of forgetting: lack of encoding, decay,
interference, retrieval failure (cue)
– Why is forgetting adaptive?
What is the role of consciousness?
– Can short presentations of stimuli be effective
– and have a lasting effect?
N.B.: you can not consciously recall the letters!
Long lasting effects of short
exposures to stimuli
Facial expressions
– 18-30 ms presentation
– Unconscious effect
– Judged neutral faces
to be more pleasant
– Höschel et al. 2001
Priming studies
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
Memory
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
Long-Term Memory
Capacity unlimited
Thought by some to be permanent
Encoding transfers info from STM to LTM –
semantically organized basis
Anterograde amnesia
Maintenance Rehearsal
Sensory
Input
Attention
Sensory
Memory
Encoding
Working or
Long-term
Short-term
memory
Memory Retrieval
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
Our hero anew: HM
Severe epilepsy, treated with surgery to
bilaterally remove medial temporal lobes,
including hippocampus
Operation 9/1953, 27 years old
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).
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
– However it is not true that he was simply incapable of
learning at all
HM able to mirror trace
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
A Taxonomy of Memory
Systems
LONG TERM MEMORY
EXPLICIT
(declarative)
SEMANTIC
(facts)
EPISODIC
(events)
Medial
Temporal
Lobe
IMPLICIT
(non-declarative)
PRIMING
(perceptual,
conceptual)
Cortex
PROCEDURAL
(skills & habits)
Striatum
ASSOCIATIVE
LEARNING
(classical & operant
conditioning)
Amygdala/
Cerebellum
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
Proof for dissociation in brain injured
Can the same be shown for healthy
adults?
Healthy amnesiacs?
Visual search task
with repeated items
Search the letter T!
Effect of midazolam /
similar to LTM deficit
Healthy amnesiacs?
Relational implicit
memory / repeated
spatial configurations
Non/relational implicit
memory / motor
acceleration
Priming Demonstration
Unscramble the
following words:
ORES
LTE PA
KTALS
TSME
LOBSOMS
ELAF
ROSE
PETAL
STALK
STEM
BLOSSOM
Priming Demonstration
ELAF = LEAF
Why not respond
FLEA?
Because flower
parts were primed
(flower power)
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 test - PRIMING
Subjects presented with target words.
Subsequent recognition phase: Targets and distractors.
Right answers measured:
Fragment Completion
Word Stem Completion
A--a--in
Bri---
Implicit memory is evidenced when Ss complete or identify
more studied than non-studied words.
Reaction-time measured (does not exclude correctness)
grsfersd
Assassin
Perceptual Identification
Assassin
Ardenisk
Lexical Decision
Degraded Word Naming
Implicit memory evidenced by faster RTs for studied words
Priming across modalities
Look at the picture .
Then when the
instructor says a
word, write it down.
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.
90
Test stimuli for Cued
Recall and Stem
Completion identical -
80
70
60
50
Amnesics
Controls
40
E.g. BRI--
30
only instructions
differed.
20
10
0
Free Recall
Cued Recall
Recog
Stem Completion
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
70
60
50
40
30
Fragment completion
performance
unchanged after 1w
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).
Two systems & a unitary one?
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) No correlation between recognition and
fragment completion.
•Unitary system
•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?
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
So what?
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 24 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 supraorbital 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.
Constructing memories
Recall the sentences from the beginning of
the lesson! Write them down.
Remember those
drawings? Can you
draw them?
Constructing continuity
Korsakoff patients – typical case
– Confabulation – making sense of airy nothing
Implicit learning
based on: Zoltán Dienes Conscious and unconscious mental processes
Implicit learning
People learn to make decisions on a task more accurately or more
quickly without being able to justify their decisions adequately.
OR:
The learning process by which people come to acquire implicit
(unconscious) knowledge.
Consider:
Acquisition of natural language, social skills, musical appreciation,
many practical skills
Implicit?
Unconscious (knowledge or learning?)
Incidental
Non-intentional
Non-verbalizable
Four common paradigms for investigating
implicit learning:
1. Artificial grammar learning
2. Dynamic control tasks (complex systems)
3. Probabilistic Category Learning
4. Serial reaction time (SRT) task
1. Artificial grammar learning
Artificial Grammars:
Subjects “trained” on grammatical sequences, then presented
with grammatical vs non-grammatical sequences.
Artificial Grammars: Reber (1967)
Group A: Learn “grammatical” letter sequences
Group B: Learn random letter sequences (using same letters)
Both groups then shown 44 letter sequences, 22 of which were
gramatical, 22 of which were random.
Group A successfully categorised 79% of the sequences
Group B were at chance
Effect lasts for years (Allen & Reber, 1980)
When questioned about the nature of the grammar, subjects generally
claim to be guessing and are unable to report any knowledge of the
rules
Many replications (but effects tend to be smaller)
Abstract or episodic
Abstract knowledge:
– Summarizes information across a series of learning
episodes
– Does not code detail
Episodic knowledge
– Codes detail
If memory is affected by similarity to originally
taught sequences, it should be episodic
– Transfer experiments! – various successful ones.
How Implicit is Implicit
Learning?
1. Underlying abstract rules
REBER himself thought so
against evidence from category learning – rules are ususally
explicit when used
2. Exemplar-based accounts
Vokey and Brooks (1992)
similarity and grammaticality controlled
some items similar (differing in one letter), but
ungrammatical
some items grammatical but differing in three letters
3. Fragment-based accounts
Those who learned bigrams or trigrams performed
as well as those who learned the entire strings
Grammaticality has no effect at all? Is it all
conscious memory then?
Dienes and Scott (2005)
In test phase, subjects rated confidence in judgment and
rated the basis of the judgment:
1. Guess – judgment has no basis whatsoever, may
as well have flipped a coin
2. Intuition – have some confidence in judgment,
but have no idea why it’s right
3. Rules – judgment based on rules acquired from the
training phase I could state
4. Memory – judgment based on memory for
training strings or parts of training strings
1.0
.9
.8
.7
.6
.5
N=
71
73
59
71
Guess
Intuition
Rules
Memory
NB: proportion correct significantly above .50 for each basis
The most direct way of testing for conscious knowledge is to test for
higher order thoughts (Dienes, Altmann, Kwan, & Goode 1995)
Independent variables:
1. In the training phase, urged to search for rules or
just memorize exemplars.
Rule search should encourage the development of conscious
structural knowledge.
2. In the test phase, classify with full attention or while
performing a demanding secondary task (random
number generation).
Secondary task should interfere with the application of
conscious structural knowledge.
Implicit basis
Explicit basis
(Guess plus intuition)
(Rules + memory)
1.00
Proportion correct classification
1.00
.90
.80
.70
.60
.50
Memorise
Learning Condition
.90
.80
.70
Attentional Conditio
No Distraction
Distraction
Rule search
Attentional Conditio
.60
No Distraction
.50
Distraction
Memorisation
Rule search
Learning Condition
When there was an implicit basis: No effect of learning condition nor
secondary task on percentage correct
When there was an explicit basis: A secondary task disrupted correct
classification in the rule search condition
2. Dynamic control tasks
Subjects interact with a simulated system, e.g. the sugar
production factory (Berry & Broadbent 1984)
Donald
Broadbent
On each trial, hire and fire workers to try to maintain the level
of sugar production at a target value.
1926-1993
Underlying equation (unknown to subjects) links current sugar
production to number of workers and past sugar production.
2. Dynamic control tasks
Berry and Broadbent (1984)
Training on the task improved ability to control the system but not
ability to answer questions about how the system worked
+Trying to consciously work out the rules impairs learning!!!
Other dynamic control tasks include:
•Interacting with a person, trying to make them friendly
•Controlling a traffic system
3. Probabilistic category learning
The weather prediction task
One or more cards presented
in a random spatial order
Amnesic patients learn it
Basal ganglia dysfunction
(Parkinson, Huntingdon)
High predictability (75%)
low predictability (58%) cards
How implicit is this?
How do people solve the task?
(1) One-Cue Learning.
Basing responses on the presence or absence of a single card (e.g., "I
predicted rain whenever I saw the triangle card.").
(2) Multi-Cue Learning.
Basing responses on the combinations of cues present on a given trial
(e.g., "I noticed that triangles and diamonds usually meant rain, and the
circles and squares meant sunny."5).
(3) Singleton Learning.
Learning the correct response to singleton patterns (A = 0001, B = 0010,
C = 0100, D = 1000), in which only a single card appears, and guessing
on the remaining trials (e.g., Memorizing the single cards, "The single
cards were the easiest, so I concentrated on those.").
4. Serial reaction time task
(Nissen & Bullemer, 1987)
On each trial a light goes
on
Just press
corresponding button
Unbeknownst to subject, sequence of lights is rule
governed
Violates rules
Rule governed
Subjects are sensitive to the presence of the sequence even
when they deny knowing that there was a sequence
Conclusion
We are unaware of pretty much of what is
going inside in our own minds
– Leaves the question of „how much” open
– Though we have different models, we have no
way of telling what is under the tip of the
iceberg – the only certainty seems to be that
there is something