1
Short-Term Memory 1
Short-Term Memory
46AC Cognition
Short-Term Memory 2
Different Kinds of Remembering
• Episodic Memory
– Events that have happened in everyday life
• Semantic Memory
– Facts
• Procedural Memory
– Skills (e.g. remembering how to ride a bike)
• Sensory Memory
• Short Term Memory
Short-Term Memory 3
Short-Term Memory
“There seems to be a presence-chamber in my mind
where full consciousness holds court, and where two
or three ideas are at the same time in audience, and
an ante-chamber full of more or less allied ideas,
which is situated just beyond the full ken of
consciousness. Out of this ante-chamber the ideas
most nearly allied to those in the presence chamber
appear to be summoned in a mechanically logical
way”
Francis Galton (1883)
2
Short-Term Memory 4
The Modal Model
Atkinson & Shiffrin (1971)
Short-Term Memory 5
Evidence for Separate Shortand
Long-term Stores
• Capacity
• Serial position effect
• Mechanisms of forgetting
• Effects of brain damage
Short-Term Memory 6
Capacity
• STS has limited storage capacity
– Digit span = “7 plus or minus 2” items
– But span of items increased by “chunking”
(Miller, 1956)
• BAFDILTUN easier to remember than 464287598
• LTS has v. large capacity
3
Short-Term Memory 7
Serial Position
(e.g., Postman & Phillips, 1965)
• Free recall of word list
• Participants tend to recall early items
(primacy effect) and later items (recency
effect)
• Recency = items in STS
• Primacy = items transferred to LTS
Short-Term Memory 8
Short-Term Memory 9
Serial Position
• Primacy and recency components open to
separate sets of influences
– Filled delay affects recency, not primacy
(e.g., Glanzer & Cunitz, 1966; Postman &
Phillips, 1965)
– Familiarity of words, age etc. affect LTM,
not recency
• These portions are products of different
mechanisms
4
Short-Term Memory 10
Different mechanisms of
forgetting
• STS = trace decay or interference (e.g.,
Peterson & Peterson, 1959)
• LTS = interference but also cue-dependent
forgetting: info is there but can’t be accessed
(Tulving, 1974)
Short-Term Memory 11
Short-Term Memory 12
Patient HM
Milner (1966)
• Surgical removal of tissue from temporal
lobes and hippocampus
• Able to recall info from earlier life but unable
to acquire new info
• No ability to consolidate new info into LTS =
anterograde amnesia
• Normal digit span
ÍNormal STS, impaired LTS.
5
Short-Term Memory 13
Patient KF
Shallice & Warrington (1970)
• Damage to left parieto-occipital region
• Good long term learning
• Poor on STM tasks (digit span = 2-3 digits)
• Normal primacy effect, reduced recency
effect (just 1 item!)
ÍShows the reverse dissociation: Impaired
STS, normal LTS
Short-Term Memory 14
Summary
• Capacity: STS limited, LTS unlimited
• Serial position effect: Primacy (LTS), recency
(STS)
• Different mechanisms of forgetting
• Effects of brain damage: Double dissociation
between STS and LTS
Short-Term Memory 15
Problems for the Modal Model
• Maintaining items in STS does not necessarily
lead to transfer to LTS (Tulving, 1966)
• Failure to learn from repeated incidental
exposure (e.g., Nickerson & Adams, 1979)
• Long-term recency effects (Baddeley & Hitch,
1977)
6
Short-Term Memory 16
Problems for the Modal Model
• Patients with impaired STS capacity (e.g.
KF) can have normal long term learning
Short-Term Memory 17
Problems for the Modal Model
• KF’s short-term forgetting of auditory
letters and digits was much worse than
forgetting of visual stimuli
• Deficit seemed to be limited to verbal
material (letters, words, digits)
• Can’t argue that KF had impaired shortterm
memory
ÍMulti-component working memory
Short-Term Memory 18
Separate visual and verbal
stores?
• Brooks (1968)
• Subs visualised a block letter
• Imagine each corner going in a
clockwise direction
• Respond “yes” if on outside, “no” if on
inside (yes, yes, yes, no, no, yes….)
• Respond vocally or by pointing
7
Short-Term Memory 19
Findings
• Subs performed more poorly when pointing
than when vocalising their response.
• Visualising a block letter used resources also
needed for reading and pointing
• If have to do both get interference
• But, visualising and responding vocally uses
different resources so performance better
Short-Term Memory 20
Complementary Task
• Subs classified words in a phrase as nouns or
not
– “A bird in the hand is not in the bush”
= “no, yes, no, no, yes, no, no, no, no, yes”
• Obtained reverse result:
– Subs better at pointing than responding
vocally
• Vocal response and pointing use different
resources
ÍSeparate visual and verbal components
Short-Term Memory 21
Dual Task Experiments
More problems for the modal model
• Subs able to maintain a digit load whilst
engaging in syntactic reasoning (Baddeley,
1986)
• Primacy effect in free recall disrupted but
not obliterated by concurrent 6 digit load.
Recency not affected (Baddeley & Hitch,
1977)
• Concurrent digit span has no effect on
accuracy of retrieval from LTM (Baddeley et
al., 1984)
8
Short-Term Memory 22
Dual Task Experiments
• Digit load should leave little capacity for
reasoning, learning, comprehending and
retrieving
• But, subs still able to do these
• Abandon unitary model
ÍOne system for storing digits, another for
reasoning, long-term storage, another for
visual/spatial material
Short-Term Memory 23
Summary
• Dual task experiments suggest there may
be:
– Separate systems for manipulating
verbal and visual material
– Separate systems for storing digits and
reasoning, learning etc.
Short-Term Memory 24
Working Memory
Baddeley (1986, 1990)
• Replaced the single STS with a multicomponent
working memory
• More emphasis on process rather than
structure
• Sought to understand the role of STS in a
range of cognitive tasks (reasoning, learning,
comprehending)
9
Short-Term Memory 25
Working Memory
Baddeley (1986, 1990)
• 3 Components:
– Central executive
• Limited capacity attentional controller
• Deals with any cognitively demanding task
– Phonological loop
• Manipulation of speech-based info
– Visuo-spatial sketchpad
• Visual/spatial coding
Short-Term Memory 26
Summary
• Evidence suggested separate short-term
and long-term storage mechanisms:
modal memory (unitary STS)
• But, dual task experiments argued against
unitary STS
• Working memory with separate verbal and
visuo-spatial components
1
Language
PSY9AC Cognition
Overview
• Structure of language
• Language comprehension
– Syntax
– Sentence parsing: is it modular?
The umpires talked to the players
The umpires talked to the players
The umpires talked to the players
The umpire s talk ed to the play er s
!i mpayr z t ck t tuw ! pley er s
Sentence:
Phrase:
Word:
Morpheme:
Phoneme: e
Discourse: Info giving: sports report
Hierarchy of linguistic structure
2
Languages consist of symbols that
represent objects or ideas.
beach
warm
bright
summer
denotation
connotations
‘SUN’
The relationship between the symbols
and the objects/ideas is entirely arbitrary.
SUN SON
DAUGHTER SON
Language symbols are discrete. Different
symbols are used to express continuous
differences.
not:
dog dog dog dog dog dog dog dog dog dog
but:
‘small dog’ ‘big dog’
3
man, bite, dog
Man bites dog.
Dog bites man.
Man bites man.
Dog bites dog.
A limited amount of discrete symbols can be
combined to create an unlimited number of
messages.
Grammar = a discrete combinatorial system
Language is generative/productive
• A person can, in principle, deal with 1020
sentences (100,000,000,000,000,000,000)
• Need one hundred trillion years to memorise
them all!
Grammar is autonomous from meaning
• Sentences can be “ungrammatical” yet
meaningful:
The child seems sleeping
Who did a book about impress you
• Others can be grammatical yet meaningless:
‘Twas brillig and the slithy toves
Did gyre and gimble in the wabe
(Lewis Carroll)
Colourless green ideas sleep furiously
(Noam Chomsky)
4
How language works
• Brains contain:
– lexicons of words and concepts they stand for
– set of rules that combine words to convey
relationships among concepts (syntax)
Phrase structure
• S ’ NP + VP The boy slept.
• NP ’ (Det) + Adj* + N The little boy.
• VP ’ V + NP The boy kicked the
ball.
• VP ’ V + S I watched the boy
kick the ball.
S
NP VP
V NP
Det N Det NP
The boy kicked the ball.
Phrase structure
5
Syntactic ambiguity
Yoko Ono will talk about her husband John Lennon who
was killed in an interview with Barbara Walters.
For sale: Mixing bowl set designed to please cook with
round bottom for efficient beating.
We will sell gasoline to anyone in a glass container.
Tonight’s programme discusses, exercise, nutrition, and
sex with Celtic forward Scott Wedman, Dr. Ruth
Westheimer, and Dick Cavett.
Pinker (1994)
Syntactic ambiguity
VP
V NP PP
discuss N
sex with
NP
Dick Cavett
VP
V NP
discuss N
with
PP
sex P NP
Dick Cavett
P
Tonight’s programme discusses sex with Dick
Cavett.
• Phrase structure conveys info about
who did what to whom etc.
The happy boy eats ice cream
‘Twas brillig and the slithy toves
Did gyre and gimble in the wabe
• Understanding the phrase structure
helps make sense of the sentence
• So how do you figure it out?
6
Sentence parsing
• Wait for end of sentence and then figure
out structure (assemble all possible
structures?)
or...
• assign words to syntactic roles as you
go along?
the
det
NP
N
S
VP
dog likes
V NP
ice cream
Garden path sentences
Fat people eat accumulates.
Since jay always jogs a mile seems like a
short distance to him.
The prime number few.
The man who hunts ducks out on weekends.
The horse raced past the barn fell.
We seem to parse sentences as we go along
Garden-path model
Frazier & Rayner (1982)
• Only one syntactical structure is initially
constructed
• Meaning is not involved in initial
structure
• The simplest structure is chosen using:
– Minimal attachment
– Late closure
7
Parsing strategies: minimal
attachment
• Attach any phrase so as to create as
few nodes (branches) as possible.
S
NP VP
V NP PP
I saw the man with binoculars.
S
NP VP
V NP
NP PP
I saw the man with binoculars.
Parsing strategies: late
closure
• Attach any new words to the phrase that
is currently being processed.
• Consider:
John said that Sarah will do the
work yesterday
• Late closure leads us to add “yesterday”
to the VP about doing the work.
8
Syntax and semantics
The defendant examined by the lawyer
turned out to be unreliable.
The evidence examined by the lawyer
turned out to be unreliable.
• Eye movement data suggest ambiguity
for both sentences (Ferreira & Clifton,
1986)
Readers use minimal attachment even
when semantically implausible.
spoken or written word recognition
syntactic processing
semantic processing
pragmatic interpretation
Garden-path model = modular theory
Syntax and semantics
(1) As the woman edited the magazine amused
all the reporters.
(2) As the woman sailed the magazine amused
all the reporters.
• Semantics favouring wrong structure greater
in (1) than (2).
• More regressions in (1) than (2); fixations in
verb region (“amused”) longer in (1) than (2).
Semantics are used in syntactic analysis.
Pickering & Traxler (1998)
9
spoken or written word recognition
syntactic processing
semantic processing
pragmatic interpretation
Interactionist view
All relevant sources of information
are available to the parser
• Semantics
• Statistical properties
– Assume most frequent role of word (e.g.,
“duck” and “train”)
– Adjectives tend to be followed by nouns
(fat people eat accumulates)
• Previous context
• Prosody
Constraint-based theory (MacDonald et al, 1994)
Unrestricted race model (Van Gompel et al, 2000)
P: The grand jury thing has its, uh, uh, uh—view
of this they might uh. Suppose we have a
grand jury proceeding. Would that, would that,
what would that do to the Ervin thing? Would
it go right ahead anyway?
D: Probably.
P: But then on that score, though we have-let
me just, uh, run by that, that—You do that on
a grand jury, we could then have a much
better cause in terms of saying, “Look this is a
grand jury, in which, uh, the prosecutor—”
How about a special prosecutor? We could
use Peterson…
10
Pragmatics
• Language in real use:
Woman: “I’m leaving you”
Man: “Who is he?”
• Figurative language (metaphor, idiom)
• Shared knowledge/beliefs between
speaker and listener
• Language comprehension is not a
sequential bottom-up process.
• Language comprehension is highly
interactive.
Summary
1
Face Recognition II 1
Computer modelling
Charlie Frowd
Face Recognition II 2
Real Neuron
(Carlson, 1986; reprinted in Ellis & Humphreys, 1999)
Face Recognition II 3
Artificial Neuron
Input to neuron:
Neti = _iWijAj
If sum of inputs >
threshold, unit is
Activated and signal is
propagated
‘neuron’/unit
Weighted connections
Dendrites Axon
2
Face Recognition II 4
Word recognition network
(McClelland &
Rumelhart, 1981)
Face Recognition II 5
Simulation of memory retrieval
(McClelland, 1981)
Inhibitory
Excitatory
Face Recognition II 6
Jets & Sharks
IAC - Interactive Activation & Competition Model
Units – 68 units
27 gang members / 27 gang members’ names
14 properties
Activation
Varies between –0.20 and +1.00
Resting activation –0.10
Connection strengths
+1 between person and properties
-1 between units in mutually exclusive ‘clusters’
Location of the ‘memory’
3
Face Recognition II 7
Burton, A.M., Bruce, V. & Johnston, R.A. (1990). Understanding
face recognition with an interactive activation model. British
Journal of Psychology, 81, 361-380.
STRUCTURAL
ENCODING
FACE
RECOGNITION
UNITS
PERSON IDENTITY
NODES
NAME
GENERATION
COGNITIVE
SYSTEM
EXPRESSION
ANALYSIS
FACIAL
SPEECH
ANALYSIS
DIRECTED
VISUAL
PROCESSING
Bruce & Young (1986)
9
Stored Descriptions
of faces (Face
Recognition Units)
Person Identities
Names
Face
Recognition
Structural encoding
Generate
descriptions of
the structure of
the face seen
Contain descriptions
of different views for
each known person
(familiarity decisions)
Specific PIN activated.
Allows access to
semantic information
4
Face Recognition II 10
Priming
Bruce & Young (1986)
Semantic priming. Facilitation through
semantic associations
Works within or between sensory modalities
Familiarity decision to Stan Laurel’s face
speeded by prior presentation of Oliver
Hardy’s face etc.
Short lived (decays)
Repetition priming: long lasting
Same stimuli repeated
Within a sensory domain
Both attributed to same mechanism in B&Y
increased activation of FRUs
11
Stored Descriptions
of faces (Face
Recognition Units)
Person Identity Nodes
Names
Face
Recognition
Structural encoding
(Description of the face)
Other routes to
identity (e.g.
Voice, name)
Repetition
and
Semantic
Priming
Face Recognition II 12
The IAC Model
PINs provide gateways to semantic
information
Occupation, interests, postal address, …
Familiarity decisions made at PINs,
B&Y – FRUs
Names are now part of semantic
information,
B&Y – last separate stage
5
13
FACE
RECOGNITION
UNITS (FRU)
PERSON
IDENTITY
NODES (PIN)
NAME
INPUT
UNITS (NIU)
SEMANTIC
INFORMATION
UNITS (SIU)
FACE NAME
Burton, Bruce &
Johnston (1990)
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
The IAC Model
FRUs
SIUs
NIUs
PINs
Tony Blair
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
Repetition Priming
FRUs
SIUs
NIUs
PINs
Tony Blair
6
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
Repetition Priming
FRUs
SIUs
NIUs
PINs
Tony Blair
Face Recognition II 17
Repetition Priming in IAC
Caused by strengthening of FRU - PIN
connections
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
Semantic Priming
FRUs
SIUs
NIUs
PINs
Tony Blair
7
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
Semantic Priming
FRUs
SIUs
NIUs
PINs
Tony Blair
Reeves
Mortimer
Reeves
Mortimer
Comedian
Reeves
Mortimer
Blair Blair
Blair
Politician
Semantic Priming
FRUs
SIUs
NIUs
PINs
Tony Blair
Face Recognition II 21
Semantic Priming in IAC
Caused by back activation from SIUs to
PINs
Raised activation of PINs allows cross
domain-priming
8
Face Recognition II 22
Computer simulation of UK and US
political leaders
Software on testing PCs
Folder called ‘iac’
Instructions
iac instucts.doc
Simulation
faces.bat
Semantic priming
(short-term) repetition priming
Face Recognition II 23
FRU NIU PINs SIU
Input Activation
Face Recognition II 24
IAC Commands
• Commands are at top of screen
• input or i. Set name then level for a unit.
Enter ‘1’ for input strength
• cycle or cy. Runs simulator for a number of
cycles. Default is 20 cycles.
• set single 1. Sets cycle step to 1.
• reset. Starts simulation again by returning
units to resting state (-0.1V). Inputs remain.
1
46AC: Cognition
Memory Processes.
David I. Donaldson
Memory involves multiple processes.
Encoding Storage Retrieval
Semantic
Records
Perceptual
Records
Binding
Context Semantic
Records
Perceptual
Records
Re-instatement
Context
What factors influence remembering?
Study Phase
DOG
TIME
DOG
TOP
BLUE
DROP
Dog…dog…
dog…dog...
Test Phase
TIME
DOG
HAND
BLUE
AIR
SHIT
OLD!
LEVELS-OF-PROCESSING THEORY
Craik & Lockheart (1972)
Assumes that the attentional and perceptual
processes operating at the time of learning
determine what information is stored in LTM.
Deeper levels of analysis produce more elaborate,
longer lasting, and stronger memory traces than do
shallow levels of analysis.
2
3 study tasks:
(1) Structural
e.g. Is the word in block
capitals?
(2) Acoustic
e.g. Does the word rhyme
with ‘cat’?
(3) Semantic
e.g. Does the word fit the
sentence ‘the cat sat on the
___’.
Craik & Tulving (1975) Depth of processing operates at encoding.
Encoding Storage Retrieval
Semantic
Records
Perceptual
Records
Binding
Context Semantic
Records
Perceptual
Records
Re-instatement
Context
These findings suggest that the quality (rather than
quantity) of processing is most important for memory.
Hyde & Jenkins (1973)
Compared intentional and incidental learning.
1) Rate the word on a ‘pleasantness’ scale.
2) Rate how frequent the word is in English.
3) Search the word for the letters ‘e’ and ‘g’.
4) Say which part of speech the word is from.
5) Say whether the word fits a given sentence.
NB. No difference between incidental versus intentional learning
Any data can be consistent with a ‘depth of
processing’ account of memory processing.
The theory is descriptive rather than predictive.
Depth-of-processing is not the only
factor that influences encoding.
Elaboration and distinctiveness are also
thought to be important…..
3
Craik & Tulving (1975)
Manipulated elaboration at encoding.
“She cooked the ______”
Vs.
“The bird flew down and carried off the struggling ______”
At test, recall was twice as good for the words
presented with complex sentences.
FLASHBULB MEMORIES
Vivid and detailed memory of a distinctive event.
BUT
People typically remember the ‘reception event’ rather
than event itself.
Debate exists as to whether flashbulb memories are
really different from memories for other events.
Brown & Kulik (1982) suggest that there is a
special neural mechanism triggered by events
that are emotional, surprising and highly
important or ‘consequential’.
McCloskey et al., (1988) investigated forgetting rates.
However, no attempt was made to assess the
emotional impact of the event.
Neisser (1982) argues that the durability
of ‘flashbulb’ memories results from
little more than frequent rehearsal.
4
What other factors influence remembering?
Remember, information needs to be available
(i.e., encoded) and accessible (i.e., retrievable).
What about effects at retrieval?
Encoding Storage Retrieval
Semantic
Records
Perceptual
Records
Binding
Context Semantic
Records
Perceptual
Records
Re-instatement
Context
Different retrieval tasks produce
different levels of memory performance.
BUT
The pattern of performance is complex.
Recognition failure for recallable words.
Both encoding and retrieval are important.
Encoding Storage Retrieval
Semantic
Records
Perceptual
Records
Binding
Context Semantic
Records
Perceptual
Records
Re-instatement
Context
Memory is dependent on an interplay between the
processing that occurs at encoding and retrieval.
ENCODING SPECIFICITY THEORY
Tulving & Thompson (1973)
Assumes that the most effective ‘retrieval
pathways’ are those that ‘re-instate’ processing
that occurred when the to-be-remembered
information was originally encoded.
The degree of ‘overlap’ in the conditions at
encoding and retrieval is critical for memory.
CONTEXT EFFECTS
Fisher and Craik (1976)
Subjects studied a series of word-pairs, with two
‘associative encoding’ tasks, emphasising either
meaning (‘CAT-DOG’) or sound (‘CAT-HAT’).
Two ‘associative retrieval’ tasks:
1) Recall a studied word associated with ‘CAT’?
2) Recall a studied word sounding like ‘CAT’?
5
Fisher & Craik (1976)
0
5
10
15
20
25
30
35
40
45
50
MEANING SOUND
Encoding Condition
% Retrieved
MEANING CUE
SOUND CUE
Encoding Condition
Retrieval Condition
INTERNAL CONTEXT EFFECTS
Teasdale & Fogarty (1979)
0
10
20
30
40
50
60
70
80
90
SAD HAPPY
Encoding Condition
% Retrieved
SAD
HAPPY
Encoding Condition
Retrieval
Condition
0
5
10
15
20
25
30
SOBER DRUNK
Encoding Condition
% Retrieved
SOBER
DRUNK
INTERNAL CONTEXT EFFECTS
Eich (1980)
Encoding Condition
Retrieval
Condition
EXTERNAL CONTEXT EFFECTS
(Godden & Baddeley, 1975)
65
70
75
80
Dry Wet
Recognition environment
Dry learning
environment
Wet learning
environment
Different effects on recall and recognition
EXTERNAL CONTEXT EFFECTS
(Godden & Baddeley, 1975)
Nothing is encoded or retrieved in
isolation, information is always encoded
within a ‘context’.
6
Multiple (interacting) factors contribute to
memory performance.
Levels-of-processing, elaboration and distinctiveness
demonstrate the importance of the organisation of
material and processing occurring at time of learning.
Task differences, internal and external context effects
demonstrate the importance of retrieval cues and the
retrieval environment.
The factors that influence remembering are not
specific to any particular type of memory.
The theory of ‘encoding specificity’ applies to
episodic, semantic and procedural memory.
Implications for studies of everyday memory
and eyewitness memory.
46AC: Cognition
Forgetting
David I. Donaldson
Can we remember everything?
Remember - there are different types of memory.
AUTOBIOGRAPHICAL MEMORY
Defined as “memory for the events of one’s live”
by Conway and Rubin (1993).
Autobiographical memories include details about
the particular place and time a particular event
occurred (the spatio-temporal context).
Debate exists as to whether autobiographical is
dissociable from episodic memory……
What methods are typically used to
investigate autobiographical memory?
(1) WORD CUEING: recalling events in response to
some sort of retrieval cue (e.g. Galton, 1883).
(2) DIARY STUDIES: writing down information
about personal events (e.g. Linton, 1975).
WORD CUEING Galton (1883).
Subject is presented with a cue word, and
asked to recollect a personally experienced
memory associated with that word.
For example: ‘cake’, ‘dog’, ‘balloon’….
Typically the participant attempts to date the
recalled incident - and rates it for various
characteristics, e.g., vividness, detail, importance.
BUT
Word cueing is unconstrained and unverifiable.
1. A RETENTION FUNCTION
An overall trend for increased forgetting
over time - memory decay.
2. A REMINISCENCE BUMP
Higher number of autobiographical
memories for the 15 - 30 years old period.
Explanations of the reminiscence bump:
(1) The 15 to 30 years old period of live tends to
be associated with the development of a stable
adult self-concept.
(2) Events occurring between 15 and 30 years of
age are somehow more distinctive than events at
other ages (Cohen & Faulker, 1988).
BUT
Reminiscence bump is also found for public
events (Schuman & Rieger, 1992).
Typically only found with older subjects.
3. INFANTILE AMNESIA
An almost total absence of autobiographical
memories from before the age of 5.
Infantile Amnesia
Memories for events between ages of 2 and 5 are
relatively infrequent.
Extremely unusual to remember events that took
place before the age of 2.
For the memories recalled, sensory & affective
elements predominate.
The memories tend to be isolated from temporal
sequence of events.
The memories tend to lack a clear sense of self.
Explaining infantile amnesia:
(1) Schactel (1947) - Organisation miss-match
Prior to language a child’s conscious experience is
organised in perceptual rather than conceptual schemas.
Experience is represented in qualitatively different ways
by adults and children (cf. encoding specificity theory).
West (1999) found little difference between
memories reported by older and younger subjects.
OLD
YOUNG
Explaining infantile amnesia:
(2) Freud (1948) - repression.
Psychodynamic theory suggest that emotionally
unpleasant or highly charged memories are repressed by
the conscious mind into the unconscious.
Lewis (1995) examined the repression account and
suggested a reworking of psychodynamic theory to better
account for infantile amnesia.
Explaining infantile amnesia:
(3) Nelson (1998) - memory system not formed.
Young children are much better at describing the features
of familiar repeated events than specific incidents.
Brain development continues throughout early childhood -
although some memory systems may be fully formed.
What if we did remember everything?
The Case of “S” (Luria, 1968)
Hiroyuki Goto, 21, the current world record holder for the most digits of Pi memorised,
required over nine hours to recite 42000+ digits [Seattle Times, 2-26-95].
S.’s, memory was not just good, it was
astoundingly good.
Luria employed very long strings of
numbers, words, and nonsense syllables but
could not detect any limit to S.’s ability to
recall them (generally without mistake).
S.'s memory was highly eidetic.
He used this technique to memorise lists,
and became a performing mnemonist.
Luria discovered that S had some other
unusual characteristics to his memory,
including synesthesia.
S was virtually paralysed when it came to
understanding speech and metaphorical ideas,
and he had an impaired ability to abstract
general knowledge from his experiences.
Forgetting is normal and desirable……..
How do we forget?
MEMORY DECAY
The forgetting curve. Ebbinghaus (1885)
Ebbinghaus provides clear evidence that
memory decays over time.
BUT
Repeatedly re-learning lists of nonsense
syllables is not ecologically valid (especially
regarding complexity and distortion).
What methods are typically used to
investigate autobiographical memory?
(1) WORD CUEING: recalling events in response to
some sort of retrieval cue (e.g. Galton, 1883).
(2) DIARY STUDIES: writing down information
about personal events (e.g. Linton , 1975).
AUTOBIOGRAPHICAL MEMORY
_ Defined as “memory for the events of one’s
live” by Conway and Rubin (1993).
Autobiographical memories include details
about the particular place and time a particular
event occurred (the spatio-temporal context).
Debate exists as to whether autobiographical
is dissociable from episodic memory……
DIARY STUDIES Linton (1982).
Systematic 6 year study of her own memory,
recording 2 events that occurred every day,
rating the events for salience, emotionality and
importance.
Every month she re-read 2 of these descriptions -
tried to remember the events described, including
the date at which they occurred.
The effect of repeated access on forgetting. Linton (1978).
Linton failed to find any strong relationship between
rated importance/emotionality and recall.
But, initial ratings did not correspond to later ratings.
“Characteristics of an event at time of encoding only
affect memorability if the same qualities are present at
time of recall”.
Two types of forgetting - depending on the type of memory.
Number of repetitions (1 - 12)
Strength of memory
Evidence suggests two influences on forgetting:
1) Decay - the memory trace is no longer
available due to the time since encoding.
2) Interference - the memory trace is no longer
accessible due to activity since encoding.
Hypothetical effects of interference and decay.
Forgetting tri-grams. Keppel & Underwood (1962).
Interference can operate both forwards and
backwards in time.
Proactive Interference
Experimental Group
Control Group
Learn List A
-----
Learn List B
Learn List B
Control group has better
memory for list B.
Build-up of proactive interference over time
Retroactive Interference
Experimental Group
Control Group
Learn List A
Learn List A
Learn List B
-----
Control group has better
memory for list A.
Build-up of retroactive interference
GROUP
Experimental
Control
TRIAL 1
378
LFP
Build-up of proactive interference over time
TRIAL 2
042
KTC
TRIAL 3
739
XPZ
TRIAL 4
JWT
JWT
Wickens et al. (1963).
Release from proactive interference.
Forgetting is both normal and desirable.
Forgetting results from both decay and
interference.
To be remembered, information must be
available and accessible.
1
Language and thought
PSY9AC
• Language = thought. Thought is just
silent, subvocal speech (Watson, 1925).
• Language ! thought. Language and
thought are independent faculties
(Chomsky, 1959).
• Language and thought are related
(Vygotsky, 1934).
• Language affects thought. (Sapir-
Whorf).
The Sapir-Whorf Hypothesis
(Benjamin Lee Whorf, Edward Sapir)
• Linguistic determinism.
Language determines the way we think.
• Linguistic relativity.
Different languages cause differences
in thoughts of speakers
2
The Sapir-Whorf Hypothesis
• Strong version:
– Language determines thought
• Weak:
– Language affects perception
• Weakest:
– Language differences affect processing on
tasks where linguistic encoding is important
Evidence: Anthropological
anecdotes
English: “It is a dripping spring”
Apache: “As water, or springs, whiteness
moves downwards”
“How utterly unlike our way of thinking”
(Whorf)
• Apaches speak differently so they think
differently
• Circular reasoning
“I am indeed a friend of the German languageand
not only now, but from long since–yes,
before 20 years already…I would only some
changes effect. I would only the language
method–the luxurious, elaborate construction
compress, the eternal parenthesis suppress, do
away with annihilate; the introduction of more
than 13 subjects in one sentence forbid; the
verb so far to the front pull that one it without a
telescope discover can.”
Mark Twain (from Pinker, 1994)
3
Evidence: Some myths.
“The Eskimo have XXX words for snow.”
“The Hopi have one word for birds, and one
word for all other flying objects (airplane,
clouds dragonfly, pilot etc.)”
“The Hopi have no lexical items describing
units of time, or past, present, and future.”
Colour terms
If no verbal labels distinguishing between two
colours, can speakers of this language
• perceive the differences between these
colours,
• memorise these colours,
• recognise these colours,
equally well as speakers of a language that
has labels for these colours?
Berlin & Kay (1969)
• There are only 11 basic colour terms
(black, white, red, yellow, blue, green,
brown, purple, pink, orange, grey).
• There is an evolutionary determined
hierarchy of colour labelling.
• There is universal agreement as to what
the best representative for each colour
term is (focal colours).
4
yellow orange
black red blue brown purple
white green pink
grey
Rosch Heider (1972)
• Research on the Dani (Papua-New
Guinea)
• Dani have only two colour words: mola
(white) and mili (black)
• Comparison of colour recognition and
memory between American and Dani
speakers.
Munsell arbitrarily divided the hue circle into 100
steps, of equal visual change in hue, with the
zero point at the beginning of the red sector.
5
Array of Munsell samples used to
elicit colour terms.
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Light
Dark
From Davidoff, J., Davies, I. & Roberson, D.
(1999) Nature, 398, 203-204
9
8
7
6
5
4
3
2
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Mili
Mola
5
4
7
1
1
1
1
1
2 2
1
1
1 4 5
1
1
1
1
1 2
1
1
1 3
2
1
2
1
2 8 2 3 4 4
1
Distribution of Dani naming and choices of best
exemplar for the 160 chip saturated array.
(Rosch Heider, 1972).
9
8
7
6
5
4
3
2
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Pink
Red
Orange
Yellow
Brown Green
Blue Purple
Pink
Red
Distribution of English naming for the 160 chip
saturated array showing the focal points for
each colour category reported by Rosch
Heider (1972).
6
Tasks:
• colour recognition memory
• 3 types of colours:
– focal: best exemplar of basic colour
categories according to Berlin & Kay (1969)
– internominal: middle of colour area for which
no language has a name
– boundary: colour at boundary between focal
or internominal clusters
Results:
US Dani
Focal 5.25 2.05
Internom. 3.22 0.47
Boundary 2.51 0.71
Mean Correct Recognition Scores
The focal representatives of universal colour
categories are better recognised regardless of
colour words in the language.
What does this mean?
• The universally better recognition of
focal colours was taken as evidence
against the Sapir-Whorf hypothesis.
• Colour perception and memorisation is
independent of language.
• ==> Thought is independent of
language.
7
Roberson, Davies & Davidoff (2000)
• Replication of Rosch-Heider’s
experiments with the Berinmo (Papua-
New Guinea)
• 5 colour words:
wapa white
kel black
mehi red
wor yellow/orange/brown
nol green-yellow/green-blue/purple
Array of Munsell samples used to
elicit colour terms.
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Light
Dark
From Davidoff, J., Davies, I. & Roberson, D. (1999)
Nature, 398, 203-204
9
8
7
6
5
4
3
2
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Pink
Red
Orange
Yellow
Brown Green
Blue Purple
Pink
Red
Distribution of English naming for the 160 chip
saturated array showing the focal points for
each colour category reported by Heider
(1972a).
From Davidoff, J., Davies, I. & Roberson, D. (1999)
Nature, 398, 203-204
8
9
8
7
6
5
4
3
2
5R 10R 5YR 10YR 5Y 10Y 5GY 10GY 5G 10G 5BG 10BG 5B 10B 5PB 10PB 5P 10P 5RP 10RP
Mehi
Wor Nol
Kel Kel
Wap Wap
Mehi
1 0
3
5
3 2
1 1
4
3 2
4
2
1
2
1
1
3
2 1
2
4 3
5
1 1
1
1
2
1
1
1
2
1 1
1 4 1 8 4 2
1
1 1 1 1 1
1 1 1 2 5 7 2 1 1 1 4 2 2
1
Distribution of Berinmo naming and choices of
best exemplar for the 160 chip saturated array
(for 25 subjects).
Results:
English US Berinmo Dani
Focal 4.90 5.25 1.73 2.05
Internom. 4.40 3.22 0.97 0.47
Boundary 4.03 2.51 1.10 0.71
Mean Correct Recognition Scores
Focal colours recognised better.
Testing discriminability.
• Task: “Find the chip”
Result:
Focal colour chips perceptually easier
to discriminate!
Re-test with a revised array of equally
discriminable colours.
9
Results:
English Berinmo
Focal 4.63 1.38
Internom. 3.88 0.94
Boundary 4.50 1.32
Mean Correct Recognition Scores
No advantage for focal colours in
recognition.
Categorical Perception
Qualitatively discontinuous perception of a physical
continuum.
Between-category distances are perceived as greater; withincategory
distances as smaller.
Predictions:
• English: Blue - green boundary
• Berinmo: Nol - wor boundary.
(Nol: green, blue, purple; wor: yellow, orange, brown,
khaki)
Equidistant stimuli across a category boundary:
wor nol
green blue
English
10
Predictions:
• English: Blue - green boundary
• Berinmo: Nol - wor boundary.
(Nol: green, blue, purple; wor: yellow, orange, brown,
khaki)
Equidistant stimuli across a category boundary:
wor nol
green blue
Berinmo
Results:
Green-blue Nol-wor
boundary boundary
Berinmo 20.75 25.38
English 23.00 14.38
Mean number of choices (out of 32) which were in
line with predictions.
Categorical perception follows category
labels in each language.
What does this mean?
• Colour labels in the language affect
similarity judgements.
• ==> Language affects thought?
11
Counterfactuals
• English grammar allows subjunctive
construction:
“If John were to go to the hospital he
would meet Mary”
• Not so in Chinese:
“If John is going to the hospital…but
he is not going to the hospital…but if he
is going he meets Mary”
• Chinese poorer at counterfactual reasoning
task than Americans (Bloom, 1981)
Spatial reasoning
• Space coded relatively (left, right, up etc.) or
absolutely (north, south etc.)
• Choice of coding system in reasoning tasks
determined by dominant system in language
(Pederson et al, 1998)
Conclusion
• There is some evidence that language
affects thought, memory, and
categorisation.
• Support for weak and weakest versions
of the Sapir-Whorf hypothesis
1
Higher level cognition:
Judgement
PSY9AC Cognition
A town is served by two hospitals. In the larger
hospital about 45 babies are born every day
and in the smaller hospital about 15 babies are
born each day. As you know, the overall
number of males born is about 50%; however,
the exact percentage varies from day to day.
For a period of one year, each hospital
recorded the number of days on which more
than 60% of babies born were boys. Which
hospital recorded more such days?
A) The larger hospital
B) The smaller hospital
C) Both about the same (i.e., within 5% of each
other)
Kahneman & Tversky (1972)
H T H T T H T T T T T T T T H T H H H H
T H T H T H H T T H H T H T T H T T H H
Coin Tosses
2
Cumberland River Thames
Regent’s
Park
Points of Impact of 67 V-1 Bombs in Central London
Gilovich (1991)
Cumberland River Thames
Regent’s
Park
Points of Impact of 67 V-1 Bombs in Central London
Gilovich (1991)
Linda is 31 years old, single, outspoken,
and very bright. She has a degree in
philosophy. As a student, she was deeply
concerned with issues of discrimination
and social justice, and also participated in
anti-nuclear demonstrations. Which of the
following alternatives is more probable?
A) Linda is a bank teller
B) Linda is a bank teller and is active in
the feminist movement.
After Tversky & Kahneman (1983)
3
Heuristics and biases
Kahneman & Tversky (1973, 1974)
• Judgements of probability based on use
of several “rules of thumb”:
– Representativeness
– Availability
– Adjustment and anchoring
• Reliance on these heuristics leads to
systematic biases.
Representativeness
• Assumption that each member of a
category is “representative” of that
category
• Assumption of homogeneity of category
– “like goes with like”
– Effects resemble causes
– Momentous events must have momentous
causes
Representativeness
• Insensitivity to sample size
• Misconceptions of chance
• Insensitivity to base rates
• Misconceptions of regression
4
Neglect of base rates
I have a friend who is a professor. He
likes to write poetry, is rather shy, and is
small in stature. Which of the following is
his field:
A) Chinese studies or
B) Psychology?
cf. Kahneman & Tversky (1973)
Neglect of base rates
Dick is a 30 year old single man. His hobbies
include home carpentry, sailing and
mathematical puzzles.
Is this person more likely to be:
A) an engineer or
B) a lawyer?
Kahneman & Tversky (1973)
Neglect of base rates
The following describes someone drawn from a
population of 70 lawyers and 30 engineers.
Dick is a 30 year old single man. His hobbies
include home carpentry, sailing and
mathematical puzzles.
Is this person more likely to be:
A) an engineer or
B) a lawyer?
Participants ignored the base rate
5
Neglect of base rates
I’m having chest pains so I’ve got heart
disease.
No chest pain 0
Chest pain 10
Heart disease
Neglect of base rates
I’m having chest pains so I’ve got heart
disease.
No chest pain 0 10,000 10,000
Chest pain 10 990 1,000
Heart disease No heart disease Total
Prob. of chest pain with heart disease = 1%
Regression to the mean
• If two variables are imperfectly related,
extreme values on one variable tend to
be matched, on average, with less
extreme values on the other.
• Tall parents tend to have tall children
but not as tall (on average) as they are
themselves.
6
Misconceptions of regression
• People do not expect regression when
it’s bound to occur
– Predictions are insufficiently regressive
• Regression fallacy
– Explain regression with spurious causal
relations
Tom Cruise Anne Bancroft
Joan Crawford Ricky Gervais
Tony Blair George Bush
Arnold Schwarzenegger Laura Dern
David Beckham Rachel Griffiths
Susan George Lana Turner
Paul McCartney Orlando Bloom
Jody Foster Kathy Bates
Availability
• People assess the frequency of a class
or the probability of an event by the
ease with which instances or
occurrences can be brought to mind.
7
Availability
• Biases due to retrievability of instances
– Familiarity
– Recency
– Salience
Imagine you picked someone at random from
the population. Will that person be more likely
to die of cause A or cause B?
Cause A Cause B
Homicide Appendicitis
Car-train collision Drowning
Measles Smallpox
Botulism Asthma
Appendicitis Pregnancy
From Lichtenstein et al (1978)
Availability
• Biases due to retrievability of instances
– Familiarity
– Recency
– Salience
• Illusory covariation
8
Illusory covariation
• Availability can bias judgements of the
frequency with which two events co-occur
• e.g., Chapman & Chapman’s (1971)
Rorschach study
• Events which are perceived to be strongly
associated are incorrectly judged to cooccur
frequently
• Confirmation bias (e.g., Gilovich, 1991)
Confirmation bias
Thinking of
best friend
Thinking of
boyfriend
2
Best friend
rings
6
Boyfriend
rings
Weird how you ring whenever I’m thinking of you
9
Confirmation bias
2 2 4
Best friend
rings
6 44 50
Boyfriend
rings
Thinking of Total
best friend
Thinking of
boyfriend
Weird how you ring whenever I’m thinking of you
Excessive impact of confirmatory information
Anchoring
• People’s estimates seem to be biased
towards some initial given starting value
(an “anchor”), even when the anchor is
unreliable.
Tversky & Kahneman (1974)
Summary
• Create something out of nothing
• Make too much of too little
• See what we expect to see
From Gilovich (1991)
1
Cognition summary
PSY9AC Cognition
Perception Cognition
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
Recognition
• Object, face and word recognition
• Evidence for stages
– Experimental, neuropsych, imaging etc.
• Comparisons between them in terms of
representations and stages
– Are faces special?
• Applied aspects of face processing
2
Attention
• Attention as a selective filter
– Early vs. late selection
• Visual attention
– Space based vs object based
– Spotlight, zoom lens etc.
• Functions of attention
– Solving the binding problem
– Role in scene perception: change blindness
Memory
• Fractionation of systems
STM
Verbal Visuospatial
LTM
episodic semantic procedural
Memory: remembering
• Fractionation of processes and factors
influencing remembering
Encoding
Levels of processing
Retrieval
Type of task: recall vs
recognition
Context effects and encoding specificity
Incidental/intentional
learning
Elaboration
Flashbulb memories
3
Memory: forgetting
• Over life span:
– Retention function
– Reminiscence bump
– Infantile amnesia
• How we forget:
– Decay
– Proactive interference
– Retroactive interference
Language
• Sentence parsing
– Depth first vs breadth first parsing
– Modular vs interactive
– Garden paths
• Language and thought
– Linguistic relativity
Control of cognition
• Limited capacity central processor vs
concept of the executive
– SAS model
• A single, unitary executive vs.
fractionation of control
– Society of mind
4
Thinking
• Making judgements
– Normative accounts vs. heuristics and
biases
Perception Cognition
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
Some links between themes
Perception
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
Cognition
Some links between themes
5
Perception
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
?
Cognition
Some links between themes
Perception
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
?
Cognition
Some links between themes
Perception
Perceptual Recognition
processes
Attention
Memory Language
Executive Processes
Thinking
Cognition
Some links between themes
6
Exam
• Two hours
• Six short answers from choice of 10
– Material from 2nd half of module
– Breadth of knowledge
• One essay from choice of 6 covering:
– Recognition; attention; memory; language;
control of cognition; judgement
– Depth of knowledge and understanding
Short answer example
• Semantic priming
This is the speeded recognition of a word, object or face
when preceded by a related word, object or face than
when preceded by an unrelated item.
Unlike repetition priming, semantic priming is short-lived
and crosses domains (e.g. words will prime pictures and
vice-versa).
There is debate as to whether semantic priming can be
considered to be categorical (items from the same
category prime each other) or associative (items which
are not from the same category but which are
associated - “daisy” and “chain” - prime each other).
Essay
• Answer question
• Marshal evidence in support of answer
• Critically evaluate alternatives
• Conceptual understanding
1
Control of Cognition 1
Control of Cognition
46AC Cognition
Dr Anna Law
Control of Cognition 2
Overview
Control in Simple and Complex Tasks
The Central Processor
The Central Executive
The Supervisory Attentional System
Fractionation of Control
Control of Cognition 3
Control in Simple Tasks
Need to configure the right task
– Enable/disable module-module links
– Input-output rules
– Decision criteria
– Preparing effectors
Monitor outcome
Optimise performance
2
Control of Cognition 4
Control in More Complex Tasks
Configure tasks
Sequencing tasks
Set memory triggers
Monitoring
Troubleshooting
Control of Cognition 5
The Central Processor View
General purpose
Limited Capacity
Single “channel” (Broadbent, 1958) or
limited attentional “resource”
(Kahneman, 1973)
Control of Cognition 6
Atkinson & Shiffrin’s (1971)
Modal Model
Parallel processing of input
Info selected for entry into a short-term store
Short-term store: Control processes
– Selection
– Rehearsal
– Coding
– Decision making
3
Control of Cognition 7
The Modal Model
Atkinson & Shiffrin (1971)
Control of Cognition 8
Problems for the Central
Processor View
The operating system analogy
– Is control really given over to specialised
processes?
– Operating system seems to run concurrently
with lower-level processes
– The real controller is the user
Simultaneous performance of two “controlled”
tasks
Control of Cognition 9
Dual Task Performance
High level tasks need the central
processor
Only available to serve one input at a time
Predicts strict limits on dual task
performance
4
Control of Cognition 10
Spelke, Hirst & Neisser (1976)
Two tasks:
– Read stories
– Write to dictation
Initially poor
After 85 hours practice (17 weeks)
– Normal reading speed + comprehension
– Semantic processing of dictated words
Control of Cognition 11
Allport et al. (1972)
Two tasks simultaneously:
– Sight read piano pieces
– Shadow a spoken passage
Performance on both tasks together no worse
than when performing each task alone
Í Incompatible with a central processor
bottleneck
Í Suggested a multi-processor model
Control of Cognition 12
The Concept of an Executive
Modulates the activity of other systems rather
than seizing control
Involved in:
– Planning
– Monitoring
– Maintaining connections between modules
– Troubleshooting
5
Control of Cognition 13
The Central Executive of Working
Memory
In the Baddeley & Hitch (1974) model of
working memory, a Central Executive coordinates
the operation of specialised subsystems
Has been criticised as a poorly-specified
“homunculus”
Control of Cognition 14
The Working Memory Model
(Baddeley, 2000)
Central
Executive
Visuo-spatial
Sketchpad Episodic Buffer
Phonological
Loop
15
The SAS Model
Normal & Shallice (1986)
Special-Purpose Cognitive Subsystems
– Object recognition, spatial processing etc.
Schemata
– Programs which “run” on the subsystems (e.g,
overtaking, braking, catching etc)
– Switch in connections between modules, set
variables (what to catch etc.), modulate activity
of subsystems
Trigger Data Base
– Conditions for activating schemata
6
The SAS Model
Normal & Shallice (1986)
Control of Cognition 17
The SAS Model
Mechanisms of Control
Contention scheduling:
– Selects appropriate schemata to control
behaviour
Inhibition between activated schemata
Í When competing for same subsystems, only
the strongest wins
Supervisory Attentional System (SAS):
– An executive
– Biases contention scheduling
The SAS Model
Normal & Shallice (1986)
7
Control of Cognition 19
The SAS
Needed when tasks:
– require planning
– need troubleshooting
– are ill-learned or novel
– are dangerous or difficult
– require overcoming a habitual response
Works by top-down biasing of schemata
Control of Cognition 20
Evidence for the SAS
Introspection/Observation
– Slips of Action (Reason, 1984)
Capture Errors
Cross-Talk Errors etc.
Í Nicely explained by SAS model
Neuropsychology
– Frontal Lobe Syndrome
E.g. Utilisation behaviour (Lhermitte, 1983,
Shallice et al., 1989)
Í Damaged SAS
Control of Cognition 21
Central Executive of WM = SAS?
Baddeley (1986) proposed that the SAS
might be a possible model for the Central
Executive of working memory
But still a lack of specificity about how a
unitary executive or supervisory system might
work
Fractionation of control processes
– (Baddeley, 1996; Shallice, 2004)
8
Control of Cognition 22
Fractionation of the Executive
No single central executive (e.g., Allport,
1989; Logan, 1985)
The “society of mind” (Monsell, 1996)
Executive control could be handled by a
related but separable set of processes, rather
than a single system
– Evidence from neuropsychology
Control of Cognition 23
Fractionation of the Executive
Miyake et al. (2000)
– Mental set Shifting (task-switching)
– Updating and monitoring of info in WM
– Inhibition of prepotent responses
Logie et al. (2004)
– Dual-task co-ordination
More complex concepts like “planning”
Some level of control needed for even the
simplest tasks
Control of Cognition 24
Summary
The control of cognition is poorly understood
Early theories emphasised a central processor or
bottleneck
Later concepts involved executive or supervisory
systems that co-ordinated or biased lower-level
systems
More recently, attempts have been made to
fractionate the executive into individual control
processes
1
Frontal Lobe Syndrome 1
Frontal Lobe Syndrome
46AC Cognition
Dr Anna Law
Frontal Lobe Syndrome 2
Overview
Case study: Phineas Gage
General characteristics of frontal lobe
damage: the frontal lobe syndrome
The relationship between the frontal lobes
and executive control of cognition
– Does frontal lobe syndrome equate to a
damaged executive/SAS?
3
Phineas Gage
Harlow (1868)
A railway worker in 1848
An explosion caused an
iron spike to shoot right
through his head
He survived! But with
extensive damage to
frontal lobes
2
Frontal Lobe Syndrome 4
Phineas Gage
Harlow (1868)
Before accident….
“most efficient and capable” man.
After accident...
“…at times pertinaciously obstinate, yet
capricious and vacillating, devising many plans
of future operation which are no sooner
arranged than they are abandoned.”
Frontal Lobe Syndrome 5
Phineas Gage
Harlow (1868)
Language and memory appeared largely intact
Showed general impairments in control:
– Disinhibited behaviour
– Antisocial
– Changes in mood and personality
Frontal Lobe Syndrome 6
3
Frontal Lobe Syndrome 7
Other Frontal Lobe Patients
E.V.R (Eslinger & Damasio, 1985)
– Unable to make decisions
L.E. (Shallice et al., 1989)
– Unable to inhibit action plans
Í Utilisation behaviour
J. (Damasio & Van Hoesen, 1983)
– No spontaneous speech but could repeat
words or sentences
Frontal Lobe Syndrome 8
Frontal Lobe Syndrome
Preserved IQ in many cases
But often have problems coping with everyday
life
Impairment seen on tests that seem to tap
“executive control” systems
Shallice (1982, 1988): Frontal Lobe Syndrome
= Damage to the SAS
Frontal Lobe Syndrome 9
The Supervisory Attentional
System (SAS)
Needed when tasks:
– require planning or decision making
– need troubleshooting
– are ill-learned or novel
– are dangerous or difficult
– require overcoming a habitual response
Works by top-down biasing of schemata
4
The SAS Model
Normal & Shallice (1986)
Frontal Lobe Syndrome 11
Does frontal lobe syndrome =
damage to the SAS?
(Shallice, 1988)
Frontal Lobe Syndrome 12
Damage to SAS Í patients unable to
interrupt and change ongoing activity =
perseveration
5
Perseveration Errors
Luria (1966)
A patient is planing a piece of wood; he goes
on inertly planing until not only is there
nothing left of the piece of wood but he is
planing the bench beneath
A patient making a speech repeats part of it
over and over again
A patient is asked to sign his name and does
so. He is now asked to draw a figure, but
instead signs his name again
From Monsell (1996)
14
Wisconsin Card Sorting Test
Frontal Lobe Syndrome 15
Damage to SAS Í patients should find it
difficult to overcome habitual responses
– Utilisation behaviours
– Stroop task
6
Frontal Lobe Syndrome 16
Stroop Procedure
Perret (1974)
Dots: Words: Colours:
• LONG BLUE
• AND RED
• VERY BLUE
• BUT GREEN
• HEAVY RED
• SHORT BLUE
• NEAR GREEN
• WITH BLUE
Frontal Lobe Syndrome 17
Damage to SAS Í patients should have
problems in planning and monitoring
– Verbal Fluency
– Multitasking
– Cognitive Estimates
– Tower of London
Frontal Lobe Syndrome 18
Verbal Fluency
Phonemic (letter) fluency
– Think of as many words as possible beginning
with the letter F
Semantic fluency
– Think of as many types of bird as possible
Requires a novel strategy/plan for retrieving
items from long-term memory
Patients with focal frontal lesions impaired (Henry
& Crawford, 2004)
7
Frontal Lobe Syndrome 19
Shallice & Burgess, 1991
Developed 2 tests of Multitasking
Six Elements Test
– Attempt part of each of 6 sub-tasks in a
limited time
Multiple Errands Test
– Run a list of errands in a shopping centre
“Buy a loaf of brown bread”
“Find out the name of shop likely to have the
most expensive item”
Frontal Lobe Syndrome 20
Cognitive Estimates
Shallice & Evans (1978)
What’s the length of the average person’s
spine?
What is the best paid occupation in Britain?
What’s the height of the largest building in
Britain?
How many camels are there in Holland?
Frontal Lobe Syndrome 21
Tower of London Test
Shallice (1982)
Initial
Position
Goal Position
(no.2)
Goal Position
(no.6)
Goal Position
(no.10)
2 moves 4 moves 5 moves
Patients with left frontal damage were severely impaired
8
Frontal Lobe Syndrome 22
Does frontal lobe syndrome =
damage to the SAS?
(Shallice, 1988)
Frontal Lobe Syndrome 23
Dysexecutive Syndrome
Baddeley (1986) proposed that the SAS might be
a possible model for the Central Executive of
working memory
However, he later became cautious about
equating CE functions with the frontal lobes
Baddeley and Wilson (1988) proposed that the
term “Dysexecutive Syndrome” should be used
instead of “Frontal Lobe Syndrome”
– defined by impairment in function, not location
of lesions
Frontal Lobe Syndrome 24
9
Frontal Lobe Syndrome 25
Fractionation of the Executive
Deficits of frontal patients do not necessarily
indicate a unitary executive system
Dissociations in performance of “frontal” tests
– (Shallice & Burgess, 1991)
Poor at multitasking
Good at card sort and verbal fluency
– EVR (Eslinger & Damasio, 1985)
Poor decision making
Normal at card sorting
Frontal Lobe Syndrome 26
Problems with “Frontal” or
“Executive” Tests
In healthy people, performance on different
tests is not strongly correlated (Miyake et al.,
2000)
Tests suffer from “task impurity” – involve
contributions from lower-level cognitive
processes (Rabbitt, 1997)
They have poor reliability and validity (Phillips,
1997)
Frontal Lobe Syndrome 27
Review article – Andres (2003)
Argued against a one-to-one link between
executive processes and the frontal lobes
– Executive processes involve a distributed
cortical network - not only frontal lobes
– Patients without any evidence of frontal
damage do present with executive deficits
– Patients with frontal lesions do not always
show executive deficits
10
Frontal Lobe Syndrome 28
Summary
Much debate about the frontal lobes
An influential view is that they are responsible for
executive control functions
– Disorganised and disinhibited behaviour of
patients
– Deficits on “executive” tests
Recently this has been questioned, especially as
executive control itself is increasingly seen as a
fractionated rather than unitary system