Emotion
High-Yield Summary
- Emotion has three components: physiological (ANS-driven arousal), behavioral (facial expressions, body language), and cognitive (subjective interpretation).
- Paul Ekman: 6 universal emotions (often expanded to 7 with contempt) — happiness, sadness, surprise, fear, disgust, anger (+contempt). Expression is universal; culture shapes the experience/interpretation.
- Emotions are evolutionary adaptations — primal emotions (fear) evolved first; social emotions (guilt, pride) evolved later, requiring more complex social cognition.
- Three theories differ on the sequence of emotion's components: James-Lange (arousal → labeled emotion), Cannon-Bard (simultaneous, via thalamus), Schachter-Singer/two-factor (arousal + cognitive appraisal of context).
- Limbic system (amygdala, thalamus, hypothalamus, hippocampus, fornix, septal nuclei, cortex parts) underlies emotion. Amygdala = fear + implicit emotional memory; hippocampus = explicit emotional memory; hypothalamus = homeostasis/neurotransmitters; thalamus = sensory relay.
- Facial-expression interpretation is lateralized (right hemisphere dominant, temporal + some occipital lobe). Prefrontal cortex emotional valence is lateralized: left = positive, right = negative.
- Autonomic nervous system produces emotion-specific physiological patterns (Levenson, Ekman, Friesen) — e.g., skin temp decreases with fear, increases with anger; heart rate increases with fear/anger, decreases when happy.
Key Terms
- Cognitive appraisal (Schachter-Singer)
- Consciously analyzing environment in relation to one's own arousal to determine which emotion is felt.
- Amygdala
- Limbic structure most associated with fear; handles implicit (unconscious) emotional memory.
- Hippocampus
- Limbic structure for long-term and explicit (conscious) emotional memory formation.
- Vagus nerve
- Cranial nerve relaying peripheral organ info back to CNS — key evidence complicating Cannon-Bard's account of severed afferent pathways.
- Ventromedial prefrontal cortex
- Subregion key to decision-making and controlling amygdala-generated emotional responses.
Three Theories of Emotion
| Theory | Sequence |
|---|---|
| James-Lange (James, Lange) | Stimulus → physiological arousal → brain labels the emotion based on that arousal |
| Cannon-Bard (Cannon, Bard) | Thalamus sends signals simultaneously to sympathetic NS and cortex — physiological + cognitive occur at once, independently |
| Schachter-Singer (two-factor) | Arousal occurs, then cognitive appraisal of the surrounding environment determines which specific emotion is felt |
Explicit vs. Implicit Emotional Memory
| Explicit (hippocampus) | Implicit (amygdala) |
|---|---|
| Conscious episodic memory of having felt an emotion | Unconscious storage of the feeling itself |
| You recall that you felt something | A similar event can retrigger the feeling without conscious recollection of the original event |
Common MCAT Trap
- An experiment manipulating a subject's interpretation of an otherwise identical arousal state is testing Schachter-Singer, not James-Lange or Cannon-Bard.
- James-Lange predicts people with spinal cord injuries (no sympathetic feedback) should show decreased emotion — this was disproven, a known weak point of the theory.
- Don't mix up amygdala (implicit/unconscious emotional memory) with hippocampus (explicit/conscious emotional memory) — re-experiencing a feeling without recalling why is implicit (amygdala).
- Left prefrontal cortex = positive emotion; right prefrontal cortex = negative emotion. Facial-expression interpretation itself is right-hemisphere dominant — don't conflate the two lateralization facts.
Quick Recall
An experiment injects epinephrine, then places subjects in either a euphoric or an angry-actor environment, and finds subjects report the emotion matching their environment. Which theory does this support?
Which limbic structure handles implicit, unconscious emotional memory?
A patient with damage to the left prefrontal cortex would be expected to show a deficit in which valence of emotion?
What critique complicates the Cannon-Bard theory's original cat experiments (severed afferent neurons)?
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