Upload
others
View
8
Download
0
Embed Size (px)
Citation preview
1
Emotion
Why emotion in cognitive science?
recent work (LeDoux, Damasio)
emotion closely tied to• thought
• perception
• decision making
• learning
unconscious computations underlieconscious decision
Disciplines and Methods clinical and counseling psychologists
introspection and psychoanalytic- unconscious
physiologists response of body to stress
psychiatrists emotions out of control
neurologists often the first screening
experimental psychologists affects on behavior, social interaction, effectiveness
neuropsychologists
Neurophysiologists studying emotion in animals (Le Doux)
Methods
• fear conditioning
• anatomical tracing
• lesion and ablation
• behavior
Historical Perspective onEmotion versus Cognition
Why not part of cognitive science?
Roots of the ideas (LeDoux)
Greek preoccupation with rationality Man as a rational thinker
Philosophy - the modern mind preoccupation with consciousness
Decartes - “I think therefore I am”
humans are conscious
humans are above animals
Freud - the unconscious is…
home of primitive instinct
link between humans and animals
an enormously important component of thehuman psyche…
rationality is there to suppress….
2
Cognitive science
resurrects the Greek idea of mind
rationality and its “side-kick” - language
human mind• “carefully engineered machine”
no place for “animal mind”
time to reevaluate “science of mind”
failure of logical computation
emphasis on neural computation
evolution of adaptive systems
progress of neuroscience
Le Doux’s Perspective on Emotion
not just 1 thing each emotion best studied in isolation
• fear - different brain areas, different functions
• disgust
• happiness
• depression/sadness
Emotional behavior highly conservedthrough evolution 4 F’s
• fight
• flight
• feeding and ….
Emotional responses
• freezing, heart rate, autonomic …etc.
When emotions occur in animals withconsciousness…..
emotions are experienced consciously
generated by unconscious processes
once aroused -> feelings “conscious”
post-hoc analysis• love, annoyance, anger
– basically cognitive
Labeled conscious feelings, like love, hate, etc.red herrings
not worthy of scientific study
part of the post-hoc analyses
3
Emotion can be studied with animal models
animal and human brains more comparablehere than anywhere else!
Emotional feelings qualitatively same a anyother conscious state
That is an apple - ah ha!
I’m mad!
Emotions happen to us passively
though we can try to manipulate them
Emotions powerful behavioral motivators
love, hurt, anger, insult - war, etc.
Where in the brain is emotion? lesion/ablation approach
decorticate animals showed normal emotion• cats - provoked…crouched, etc.
• autonomic arousal– pupil dilation
– blood pressure increases
– piloerection
still somewhat abnormal• unregulated….
4
Cannon and Bard (29)
stimulus
thalamus
hypothalamus
body reaction
Papez Circuit - Limbic Brain
Herrick’s idea’s (early 20th century)
brain evolution lateral surface -phylogentically newer
medial part - phylogenetically older
stimulus
thalamus
hypothalamus
body reaction
Stream of Feeling
stimulus
thalamus
cortex
Stream of Thought
stimulus
thalamus
cortexcingulatehippocampushypothalamusthalamus
Emotion from integration circuit
5
Question
If we are to study emotions individually…. How many emotions are there?
What are they?
How do we decide they are separate?
How many emotions?Ekman’s list
fear
sadness
happiness
anger
disgust
surprise
W. James
“It is difficult to imagine emotions in the absence of their bodily expressions”
J. LeDoux
“We know our emotions by their intrusions”
When they really intrude!
How many emotions?
fear - phobias
sadness - depression
happiness - mania
anger - aggression
disgust - OCD
Study emotions individually
LeDoux’s working hypothesis
If correct that they are different systems good choice
If not… nothing lost by focusing on one
6
Why Fear?pervasive and diverse in humans
predator, etc….
intellectually-based existential fear
prominent and diverse in psychopathology phobias
• snakes, cats, heights, open spaces, social situations...
Expressed similarly in humans and animals withdraw
immobility (freezing)
defensive aggression
submission
Repertoire
startle
orientation
freeze, flight, or attack
cat and rat…first rat startles, next orients,.. If far -> flee
If close ->freeze
If unsuccessful - vocalize and attack
Fear conditioning
standard classical conditioning learning to pair a previously objective
stimulus…e.g., tone, etc.
to a painful outcome…..
the tone elicits fear…without the painfuloutcome….
A tool for studying emotion in animals...
Fear Conditioning
fruit fly
marine snail
fish
lizard
pigeon
rabbit
rat
cat
dog
macaque
human...
Rat
fear condition rat to sound-shock pair
Which parts of the auditory system required? dissect out the neuro-pathways
7
Auditory cortex damage did not extinguish conditioning
Where else? thalamus (MGN)???
• anatomical tracers…
• from MGN
reveals projections to 4 areas...
Systematically ablate each area in turn…
result clear amygdala destruction
• no fear conditioning
More evidenceStimulation of amygdala
(Kapp)
produces a fear response
activation of autonomic nervous system
So what does the amygdala do?
Find areas to which the amygdala projects anatomical forward tracing methods
Central gray
Lateral hypothalamus
Paraventricular hypothalamus
Reticulopontis caudalis
8
Conclusions and Implications
fear can bypass the neocortex
what about the sensory pattern recognitionsystems in cortex…????
pattern detection in the thalamus???
High Road and Low Road
What if the fear trigger is similar to a non-fear trigger….
Schneiderman et al… similar tones…1 with shock 1 without
at first rabbits over-generalize
eventually learn to fear only the “bad” one
destruction of auditory cortex• Over-generlize again
Low road for speed!
The inputs of the fear system
sensory thalamus What we have been talking about
sensory cortex higher level discriminations….
cognitive appraisal…• e.g. seeing a gun
9
rhinal cortex and hippocampus memory
medial prefrontal extinction
inhibition!
Summary -What is an emotion?
a brain process• physiological reaction to stimulus
psychological reaction to a perception• danger, life-altering event
system of drives, actions, fulfillment• drives - stimulus -> glucose drop, etc
• action - eat
• satisfaction - contentment
Taxonomy
primary emotions hard-wired through limbic system
• stimulus activates system– associatively conditioned
– innate - ? (facial expressions)
physiological response• hypothalamus - endochrine, neurotransmitters
• internal response (ANS)
Taxonomy
secondary emotions• conscious deliberate cognitive evaluation
– possible simultaneous activation of limbic
• primary route thereafter
Decision-making and EmotionA Case Study
Phineas Gage accident - damage to frontal cortex
Harlow’s study Pre-accident
• responsible, good guy, leadership qualities, polite
Post-accident• inability to plan, make good decisions, social sense
– otherwise cognitively and perceptually intact
Emotion and Human Decision-making
10
3D reconstruction of damage Gage (H. Damasio)
prefrontal cortex bilaterally
ventral and inner surfaces affected
external surfaces preserved - working memory
“ventromedial”• known to be involved in decision-making
Modern Phineas Gage
Elliot brain tumor patient
ventromedial prefrontal damage
post-surgery language, mathematics, MMPI
couldn’t make a good decision - like Gage
IQ > normal
Wechsler adult intelligence scale > normal digit spans, etc.
language comprehension > normal
Benton face matching task - fine
all other perceptual tests - normal
Standard Tests for Elliot
Standard Frontal Lobe Tests
Wisconsin card sort task cards that can be sorted by color or form, etc
person must switch criteria
Elliot did fine
Tests with incomplete knowledge How many giraffes are there in New York City?
Elliot normal
Change of perspective
Began to notice the disaffected state of Elliot failed to see evidence of any emotion
later test (Tranel)• emotion-packed images
• Elliot recognized the emotion he had felt previously
• but was unaffected….
Does the impairment in decision makingrelate to the impairment in feeling?
11
Dissecting the decision process
decision-making
read problem descriptions
specify alternatives
excellent
Tests for Elliot
maybe he doesn’t understand consequences
consequence prediction x -> y read decision descriptions
predict what follows
excellent
maybe he can’t initiate the process
means-end analysis given a goal - asked to design a way to reach
scenarios from personal and social domain
excellent
maybe he can’t consider right-wrong
moral reasoning test given a difficult moral problem - Kohlberg test
must choose lessor of two evils, etc.
excellent
All said and done…..
Elliot replies:
“but I still wouldn’t know what to do!”
12
Emotion and Reasoning
Somatic marker hypothesis (Damasio)
• decisions involve a body-based marker that is theresult of a secondary emotion
Example decisions
glucose drops….get hungry unconscious
not overt knowledge
no inference
no display of options….until you “feel” hungry
object falls - “decide” to get out of the way unconscious
automatic
no inference
decide who to vote for
what to major in
to pursue a friendship or romance
whether or not to fly in bad weather
what % of money to put in stocks
These are seen with a conscious evaluativeand logical basis….
Possibilities
pure reason hypothesis generate a cost-benefit analysis
decide the option with the cost-benefit ration
situations complex, and quantification difficult
Possibilities
Somatic marker hypothesis associative connection to previous experience
BEFORE - cost-benefit
gives a “gut” feeling• positive
• negative
prescreens possibilities…..
13
contrast between experience and perception
What is emotion for?
• emotion as communication– primitive language
» expressions, posture, gait - e.g., Blair Witch
» teaching young what to fear, etc.
This despite…...
Psychological data
Economics (R. Frank) “Many actions, purposely taken, with full
knowledge of their consequences, areirrational”
Not just minor decisions (J. L. Borges) description of the Falkland’s war
“two bald men fighting over a comb”