Emotions, Aggression, and Stress

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Emotions, Aggression, and Stress
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15 Emotions, Aggressions, and Stress

• What Are Emotions?
• Broad Theories of Emotion Emphasize Bodily
  Responses
• How Many Emotions Do We Experience?
• Emotions from the Comparative/Evolutionary
  Viewpoint

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15 Emotions, Aggressions, and Stress

• Individuals Differ in Their Emotional
  Responsiveness
• Do Distinct Brain Circuits Mediate Emotion?
• Neural Circuitry, Hormones, and Synaptic
  Transmitters Mediate Violence and Aggression

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15 Emotions, Aggressions, and Stress

• Stress Activates Many Bodily Responses
• Stress and Emotions Are Related to Some Human
  Diseases

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15 What Are Emotions?

• Four aspects of emotions
• 1. Feelings
• 2. Actions
• 3. Physiological arousal
• 4. Motivation

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15 Broad Theories of Emotion Emphasize Bodily
Responses

• Folk psychology says autonomic responses (like
  stomach churning) are caused by emotions.
• JamesLange theory suggests the emotions we
  feel are caused by bodily changes. Emotions
  differ due to different physiological responses.

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Figure 15.1 Different Views of the Chain of
Events in Emotional Responses (Part 1)
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15 Broad Theories of Emotion Emphasize Bodily
Responses

• CannonBard theory says emotions precede
  physiological responses and help deal with a
  changing environment.
• The cerebral cortex decides on the emotional
  response and also activates the sympathetic
  response.

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Figure 15.1 Different Views of the Chain of
Events in Emotional Responses (Part 2)
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15 Broad Theories of Emotion Emphasize Bodily
Responses

• Schachters cognitive theory suggests that
  physiological responses are interpreted in terms
  of the stimuli.
• An emotional state results from the interaction
  of physiological activation and cognitive
  interpretation.

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Figure 15.1 Different Views of the Chain of
Events in Emotional Responses (Part 3)
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15 Broad Theories of Emotion Emphasize Bodily
Responses

• In Schachters theory, all physiological arousal
  is nonspecific.
• But research shows different patterns of
  autonomic responses according to positive or
  negative emotions.
• A polygraph (lie detector) measures bodily
  responses, but is not reliable.

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15 How Many Emotions Do We Experience?

• Plutchik suggests eight basic emotions, in four
  pairs of opposites
• Joy/sadness
• Affection/disgust
• Anger/fear
• Expectation/surprise

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Figure 15.2 Basic Emotions
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15 How Many Emotions Do We Experience?

• Paul Ekman says different emotions can be
  detected in facial expressions.
• Anger, sadness, happiness, fear, disgust,
  surprise, contempt, and embarrassment are similar
  across cultures.

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Figure 15.3 Universal Facial Expressions of
Emotion
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15 How Many Emotions Do We Experience?

• There is cross-cultural similarity in expression
  production, but there are culture-specific
  differences in display.
• The extent of cultural influence is under debate.
• A role of facial expression is paralinguistic
  an accessory to communication.

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Figure 15.4 Cultural Differences in Recognizing
Facial Expressions of Emotion
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Figure 15.5 A Model for Emotional Facial
Expressions across Cultures
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15 How Many Emotions Do We Experience?

• Two categories of facial muscles
• Superficial facial muscles attach to facial
  skin
• Deep facial muscles attach to skeletal
  structures in the head
• Facial muscles are innervated by two cranial
  nerves the facial nerve (VII) and the trigeminal
  nerve (V).

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Figure 15.6 Superficial Facial Muscles and Their
Neural Control
Human facial muscle innervated by facial nerve
(VII) trigeminal nerve (V)
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15 How Many Emotions Do We Experience?

• Impairment of facial expressions may limit social
  interaction.
• Inhibition of facial muscles may be caused by
  Parkinsons disease or by schizophrenia.
• Bells palsy is caused by a virus and can cause
  partial paralysis.

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Figure 15.7 Bells Palsy Leaves Half of the Face
Paralyzed
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15 Emotions from the Comparative/Evolutionary
Viewpoint

• Darwin suggested that expressions and emotions
  came from a common ancestor.
• Besides expressions, he noted the similarity in
  facial musculature and nerves in human and
  nonhuman primates.

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Figure 15.8 Emotional Expression in Animals
(From Darwin, 1872)
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15 Emotions from the Comparative/Evolutionary
Viewpoint

• Redican described primate expressions relative to
  humans
• Grimace, like fear or surprise in humans
• Tense mouth, like anger
• Play face, like the human laugh

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Figure 15.9 Facial Expression of Emotions in
Nonhuman Primates
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15 Emotions from the Comparative/Evolutionary
Viewpoint

• Evolutionary psychology studies how natural
  selection has shaped behavior.
• Emotions may coordinate responses to solve
  adaptive problems.
• Cooperating with a group, choosing a mate, and
  avoiding predators may have required emotional
  adaptation.

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15 Emotions from the Comparative/Evolutionary
Viewpoint

• Some emotions are present at birth by 9 months,
  all basic emotions are present.
• Between 1824 months, self-awareness develops,
  along with embarrassment, empathy, and envy.
• Evaluative emotions (pride, guilt, regret, shame)
  develop by 23 years.

( ?? vs. ?? )
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15 Individuals Differ in Their Emotional
Responsiveness

• Individual response stereotypy is the tendency of
  individuals to have the same response patterns
  throughout their lives.
• Infants who are high reactives to stimuli with
  exceptionally strong reactions may later have
  increased phobias or fear responses.

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15 Do Distinct Brain Circuits Mediate Emotions?

• Brain self-stimulation refers to animals working
  to provide electrical stimulation to their brain
  also possible in humans.
• Brain sites that respond to self-stimulation have
  been mapped.
• Basic arousal (power) for generate emotion.

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Figure 15.10 Self-Stimulation Sites in the
Rodent Brain
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15 Do Distinct Brain Circuits Mediate Emotions?

• The medial forebrain bundle a tract that rises
  from the midbrain through the hypothalamus
  contains many sites for self-stimulation.
• The nucleus accumbens is an important target
  involved in the dopaminergic circuit.

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15 Do Distinct Brain Circuits Mediate Emotions?

• Brain lesions can affect emotions
• Decorticate rage a sudden intense rage in dogs
  with their cortex removed suggests the cortex
  inhibits rage.
• The Papez circuit interconnected brain regions
  within the limbic system, damaged in some patients

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Figure 15.11 Medial Regions of the Brain
Involved in Emotions
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15 Do Distinct Brain Circuits Mediate Emotions?

• KlüverBucy Syndrome removal of temporal lobes
  in monkeys resulted in a taming effect
• Further studies recognized the amygdala, located
  in the temporal lobe, as a key structure in the
  mediation of fear.

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15 Do Distinct Brain Circuits Mediate Emotions?

• Classical conditioning can elicit fear
• By pairing a stimulus with an aversive stimulus,
  like shock
• Eventually the first stimulus by itself can
  produce fear, including freezing and autonomic
  changes

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Figure 15.12 The Circuitry of Fear (Part 1)
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Figure 15.12 The Circuitry of Fear (Part 2)
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Figure 15.12 The Circuitry of Fear (Part 3)
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15 Do Distinct Brain Circuits Mediate Emotions?

• Different regions of the amygdala react to the
  stimulus and send a message to the central
  nucleus of the amygdala.
• The central nucleus transmits information to
  brainstem centers.

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15 Do Distinct Brain Circuits Mediate Emotions?

• Three types of emotional response are evoked
• Central gray (periaqueductal gray) pathway
  emotional behaviors
• Lateral hypothalamus pathway autonomic
  responses
• Bed nucleus of stria terminalis pathway
  hormonal responses

(see figure 15.12)
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Figure 15.12 The Circuitry of Fear (Part 4)
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Figure 15.12 The Circuitry of Fear (Part 5)
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15 Do Distinct Brain Circuits Mediate Emotions?

• Neural circuitry has been studied for other
  emotions
• Disgust, in humans activates the insula and
  putamen
• Laughter activates the prefrontal cortex

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15 Do Distinct Brain Circuits Mediate Emotions?

• The two cerebral hemispheres process emotion
  differently.
• Right hemisphere discerns or recognize other
  peoples emotions
• The left side of the face, controlled by the
  right hemisphere, is more expressive than the
  right.

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15 Do Distinct Brain Circuits Mediate Emotions?

• The two cerebral hemispheres differ in emotional
  tone.
• Damage to the left hemisphere produces depressive
  symptoms.
• Patients with damage to the right hemisphere are
  very cheerful.

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15 Do Distinct Brain Circuits Mediate Emotions?

• The hemispheres differ in recognition of emotions
  in vocal messages.
• The right hemisphere is better at identifying the
  emotional tone and the left is better at
  interpreting the meaning of the message.
• Each ear projects more strongly to the opposite
  hemisphere.

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15 Do Distinct Brain Circuits Mediate Emotions?

• Visual stimuli also produce different reactions.
• The right hemisphere
• Reacts more quickly and more accurately
• Is better at discriminating facial expressions in
  others
• Is dominant in expressing emotions

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Figure 15.13 Emotions and Facial Asymmetry
Photo (a) is judged with more emotional reaction
on facial expression than (b) or (c).
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15 Do Distinct Brain Circuits Mediate Emotions?

• Emotions are accompanied by differences in brain
  activity.
• Love bilaterally increases activity in some areas
  and decreases activity in others.
• The combination of sites is different than for
  other emotions love is unique!

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Figure 15.14 Brain Regions Implicated in
Emotions (Part 1)
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Figure 15.14 Brain Regions Implicated in
Emotions (Part 2)
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15 Do Distinct Brain Circuits Mediate Emotions?

• Brain activation during sadness, happiness,
  anger, and fear show several brain regions
  involved.
• The same brain region may participate in
  different emotions.

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Figure 15.15 Brain Regions Involved in Four
Emotions (Part 1)
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Figure 15.15 Brain Regions Involved in Four
Emotions (Part 2)
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Figure 15.15 Brain Regions Involved in Four
Emotions (Part 3)
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Figure 15.15 Brain Regions Involved in Four
Emotions (Part 4)
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15 Do Distinct Brain Circuits Mediate Emotions?

• Neuroeconomics is the study of brain mechanisms
  at work during economic decision making.
  (???????????)
• Emotional responses to gains or losses influence
  these decisions.
• The prefrontal cortex inhibits impulsive
  decisions and the amygdala reflects regret.

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Figure 15.16 Localizing Regret
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15 Neural Circuitry, Hormones, and Synaptic
Transmitters Mediate Violence and Aggression

• Aggression may be viewed as
• An inner feeling of hate and the desire to do
  harm
• An overt response, such as predatory aggression
  attack behavior directed at natural prey

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15 Neural Circuitry, Hormones, and Synaptic
Transmitters Mediate Violence and Aggression

• Androgens seem to increase aggression, but the
  correlation in humans is less clear.
• Two confounding variables
• Experience and dominance can affect testosterone
  levels winners show higher levels than losers

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Figure 15.17 The Effects of Androgens on the
Aggressive Behavior of Mice (Part 1)
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Figure 15.17 The Effects of Androgens on the
Aggressive Behavior of Mice (Part 2)
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15 Neural Circuitry, Hormones, and Synaptic
Transmitters Mediate Violence and Aggression

• There is a negative correlation between serotonin
  and aggression mice lacking serotonin are
  hyperaggressive.
• Low concentrations of serotonin are found in
  humans in alcohol-induced violence or excessive
  military violence.

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15 Neural Circuitry, Hormones, and Synaptic
Transmitters Mediate Violence and Aggression

• Dyscontrol syndrome refers to temporal lobe
  disorders that may underlie some human violence.
• Psychopaths are people incapable of experiencing
  remorse they may commit very violent acts.

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Figure 15.18 Psychopathic Impulsivity
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15 Stress Activates Many Bodily Responses

• Stress includes stress stimuli, processing, and
  stress responses.
• The alarm reaction is the initial response,
  followed by the adaptation stage.
• The exhaustion stage is the reaction to prolonged
  stress.

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15 Stress Activates Many Bodily Responses

• Under stress, the hypothalamus produces
  corticotropin-releasing hormone (CRH).
• CRH causes release of adrenocorticotropic hormone
  (ACTH) leading to cortisol release.
• Growth hormone, epinephrine, and norepinephrine
  are also released.

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Figure 15.19 Autonomic Activation during a
Stress Situation (Part 1)
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Figure 15.19 Autonomic Activation during a
Stress Situation (Part 2)
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Figure 15.19 Autonomic Activation during a
Stress Situation (Part 3)
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Figure 15.20 Hormonal Changes in Humans in
Response to Social Stresses (Part 1)
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Figure 15.20 Hormonal Changes in Humans in
Response to Social Stresses (Part 2)
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15 Stress Activates Many Bodily Responses

• Individuals differ in their response to stress.
  (stress coping)
• Stress immunization is the idea that mild stress
  early in life makes it easier to handle stress
  later in life.

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15 Stress and Emotions Are Related to Some Human
Diseases

• Psychosomatic medicine emphasizes the role of
  psychological factors in disease.
• Health psychology (or behavioral medicine)
  studies psychological influences on health.

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Figure 15.21 Factors That Interact during the
Development and Progression of Disease
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15 Stress and Emotions Are Related to Some Human
Diseases

• Main features of the immune system include
  different white blood cells.
• Phagocytes engulf and destroy germs
• B lymphocytes (B cells), formed in the bone
  marrow, produce antibodies (immunoglobulins)
  against foreign molecules

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15 Stress and Emotions Are Related to Some Human
Diseases

• T lymphocytes (T cells) produced in the thymus
  gland can act as killer cells
• Special helper T cells secrete cytokines,
  proteins that induce cell proliferation in the
  immune system

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Figure 15.22 Main Components of the Human Immune
System (Part 1)
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Figure 15.22 Main Components of the Human Immune
System (Part 2)
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Figure 15.22 Main Components of the Human Immune
System (Part 3)
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Figure 15.22 Main Components of the Human Immune
System (Part 4)
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15 Stress and Emotions Are Related to Some Human
Diseases

• The brain affects the immune system through
  autonomic nerves, and monitors immune reactions.
• The immune system acts as a sensory receptor
  system, informing the brain.
• The brain and immune system also interact with
  the endocrine system.

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Figure 15.23 Examples of Reciprocal Relations of
the Nervous, Endocrine, and Immune Systems
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15 Stress and Emotions Are Related to Some Human
Diseases

• Hormones released during stress suppress the
  immune system.
• This acts as a short-term defense mechanism,
  allowing for resources to be used elsewhere
  (escaping a predator).
• Long-term stress is detrimental to immune
  function.

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15 Stress and Emotions Are Related to Some Human
Diseases

• Psychological stress, such as depression or
  grief, decreases immune function.
• A Type A behavior pattern, marked by increased
  hostility, is associated with heart disease.