Study Notes on Emotions in PSYC234

PSYC234: Emotions

Professor Stuart Johnstone
Reference Materials
  • Kalat, Chapter 11
Previous Topics Covered
  • Neural activity
  • Biology of learning
  • Nervous system anatomy
  • Neural development and plasticity
  • Sensory systems
  • Sensorimotor system
  • Biological rhythms
Today's Topic
  • Emotions
Outline of Lecture
  • What are emotions?
  • Theories of emotion
  • Neural mechanisms of emotion
Definition and Understanding of Emotions
  • Emotions relate to feelings and behaviors, often referred to as affect.
  • Emotions can be classified as either positive or negative.
  • Researchers tend to focus more on negative affect due to its significant relationship with health outcomes.
Darwin’s Perspective on Emotion (1872)
  • Charles Darwin posited that human expressions of emotion have evolved from those found in other species.
  • Purpose of Emotional Expression: To communicate behavioral intentions effectively.
  • Success in emotional communication enhances survival and reproductive success.
  • Emotional expression serves an adaptive function.
Quote from Darwin (1872)
  • In "The Expression of Emotion in Man and Animals":
  • Emotions must have distinguishable signals; thus, they evolved in opposite directions, a concept known as antithesis.
Components of Emotion
  1. Cognitions: For example, thinking “This is a dangerous situation.”
  2. Feelings: Such as saying, “I feel frightened.”
  3. Action: Responses like running away.
  4. Physiological Changes: Such as increased heart rate (HR) and breathing rate.
Theories of Emotion
"Common Sense" View
  • Sequence of events in a frightening situation:
      - Frightening situation leads to fear.
      - Resulting actions: Running away and physiological responses (i.e., increased HR).
James-Lange Theory (1884)
  • Proposes that the conscious experience of emotions arises from the perception of autonomic arousal.
  • This means physiological changes manifest as the emotion itself.
Criticism of James-Lange Theory
  • Spinal Cord Damage: Suggests that if the spinal cord is damaged, emotional experiences should be absent since there would be no autonomic nervous system (ANS) feedback.
  • Contradictory example: If heart rate increases without apparent reason, emotions should simultaneously be felt, questioning the theory's validity.
Modern View of Emotions
  • Acknowledges that the three principal factors of cognition, action, and feeling influence each other reciprocally.
Facial Expressions of Emotion
  • Paul Ekman identified six primary facial expressions:
      - Anger
      - Fear
      - Happiness
      - Surprise
      - Sadness
      - Disgust
  • These expressions exhibit similarities across various cultures.
Applications of Facial Expression Research
  • Dr. Paul Ekman served as a scientific advisor for films such as Inside Out (2015) and Inside Out 2 (2024), which delve into emotions and family dynamics.
Facial Feedback Hypothesis
  • Examines whether producing a facial expression influences emotional experience.
  • Research by Rutledge and Hupka (1985) confirms that individuals report feeling happier when compelled to smile, and vice versa for anger.
  • Key Study: Participants holding a pen in their teeth, which enforced a smile, reported higher amusement than those holding it in their lips, which prevented smiling.
Neural Mechanisms of Emotion
  • Popular belief suggests that emotions are primarily regulated by the right hemisphere of the brain.
      - The right hemisphere is dominant for prosody and the interpretation of facial expressions.
      - Lesions in this area can significantly influence emotional perception and expression, more so than in the left hemisphere.
      - Bilateral frontal lobe lesions lead to diminished facial expressions.
Effects of Cortical Damage on Emotion
  • Emotional disruption varies, heavily influenced by the location of cortical lesions and the measurement techniques used.
  • Lesions in the frontal lobe notably reduce the frequency of facial expression, with less impact from lesions in the parietal or temporal lobes.
Statistical Data
  • Mean number of emotional expressions recorded:
      - Frontal lesions reduce expressions significantly.
Lateralization of Facial Expression
  • Facial expression is lateralized:
      - The left side of the face often exhibits more severe expressions due to control by the right hemisphere, especially in expressions like disgust.
Localization of Emotions in the Brain
  • A review of recent brain imaging studies indicates no strong evidence for specific localization of emotions.
  • No single brain area has been identified as critical for experiencing emotions, as areas often interact with various behavioral functions.
Subcortical Involvement in Emotion
  • Key Structures Include:
      1. Cingulate gyrus
      2. Anterior thalamic nuclei
      3. Septal nuclei
      4. Frontal lobe
      5. Olfactory bulb
      6. Mammillary bodies
      7. Amygdala
      8. Fornix
      9. Hippocampus
      10. Parahippocampal gyrus (part of the limbic lobe)
Amygdala's Role in Emotion
  • The amygdala regulates current anxiety levels and processes sensory information from pain, vision, and hearing.
  • It plays a role in controlling reflexive responses, such as the startle reflex mediated through the midbrain.
Effects of Amygdala Damage
  • Implications of damage include:
      1. Impaired learning of fear responses.
      2. Difficulty in retaining previously learned fear responses.
      3. Challenges in interpreting or understanding emotionally charged stimuli.
  • The amygdala is activated in response to emotional stimuli, especially facial expressions.
Case Study: Amygdala Damage (Patient SM)
  • Displays fearlessness and has trouble processing fear in social contexts.
  • While capable of drawing emotional faces appropriately, struggles to depict fear specifically.
  • Notably avoids direct eye contact, indicating a lack of appropriate social engagement, leading to potential danger due to lack of fear recognition.
Amygdala's Response to Gaze Direction
  • The amygdala's response varies with the direction of gaze:
      - Higher activation in response to direct angry faces compared to averted fearful faces.
  • Statistical Evidence: Graph showing differences in amygdala response based on face direction.
Additional Subcortical Structures and Their Functions

  1. Cingulate Gyrus:
       - Involved in emotion regulation and behavior.
       - Responds to fear based on prior experience, damage can lead to absence of fear.

  2. Hypothalamus:
       - Regulates the stress response system and biological rhythms.
       - Coordinates the hypothalamic-pituitary-adrenal (HPA) axis; damage can lead to burnout and aggression.

  3. Basal Ganglia:
       - Linked to emotional behaviors associated with reward and reinforcement.
       - Areas involved include the nucleus accumbens, ventral tegmental area, ventral pallidum; damage can manifest as negative affect or anhedonia (depression-like symptoms).

Philosophical Reflection on Emotions
  • Quoting Shel Silverstein:
      > "Underneath my outside face
      > There's a face that none can see.
      > A little less smiley,
      > A little less sure,
      > But a whole lot more like me."
True vs. Fake Expressions
  • Examination of motivations for faking smiles:
      - To reassure a friend.
      - To conceal a lie.
      - To mask true feelings.
Distinctions Between True and Fake Smiles
  • Differentiation based on two facial muscle groups:
      1. Orbicularis Oculi: Involved in genuine smiles, pulling cheeks and forehead towards the eyeball.
      2. Zygomaticus Major: Engaged in both real and fake smiles, elevating the corners of the lips.
Historical Context
  • Duchenne (1862): Identified that fake smiles predominantly involve the zygomaticus major, but not the orbicularis oculi, emphasizing the distinctiveness of genuine emotion expressions.