Emotion in the brain, the face and everyday life

Transcript

RyanNew Guinea. The psychologist Paul Ekman sits with a man from a preliterate culture that uses stone tools, a community so isolated it had never seen outsiders. Ekman asks him to show what his face would look like if friends came to visit. If his child had just died. If he were about to fight.

SoheeAnd if he stepped on a smelly dead pig. Ekman spent more than four decades after that trip researching facial expressions. And what he found changed how we think about emotion across cultures.

RyanWelcome to EPPP Prep, the podcast. I'm Ryan.

SoheeI'm Sohee. Last time was theories of emotion. Today we go into the brain, onto the face, and into daily life: how we show emotion, how culture shapes that, and how we regulate it.

RyanFirst, a distinction people blur. Emotion versus mood. The OpenStax psychology textbook says emotion typically means a subjective, affective state that's relatively intense and occurs in response to something we experience. Emotions are often thought to be consciously experienced and intentional.

SoheeMood is a prolonged, less intense affective state that does not occur in response to something we experience. Mood states may not be consciously recognized, and they lack the intentionality of emotion.

RyanPause and think. For two weeks, Dev has felt low and flat, with no clear trigger. Then a coworker insults him and he flushes with anger for a few minutes. Which is the mood and which is the emotion?

SoheeThe two weeks of lowness, prolonged, less intense, not tied to a specific event, is mood. The sharp, brief anger in response to the insult is emotion.

RyanNow the brain. The limbic system is the area involved in emotion and memory, and it includes the hypothalamus, the thalamus, the amygdala and the hippocampus.

SoheeThe hypothalamus plays a role in activating the sympathetic nervous system, part of any emotional reaction. The thalamus is a sensory relay center, with neurons projecting to both the amygdala and the higher cortex.

RyanThe amygdala processes emotional information and sends it on. And the hippocampus integrates emotional experience with cognition.

SoheeThe amygdala gets the most attention, especially for fear and anxiety. It has subnuclei, including two worth knowing. The basolateral complex has dense connections with sensory areas of the brain. It's critical for classical conditioning and for attaching emotional value to learning and memory.

RyanThe central nucleus plays a role in attention, and it connects with the hypothalamus and brainstem areas to regulate autonomic and endocrine activity.

SoheeSo if a question asks which part of the amygdala is critical for classical conditioning, think basolateral complex.

RyanAnd context changes what the amygdala learns. In rat pups, an odor paired with shock while the mother was absent increased amygdala activation, and the pups learned to avoid the odor.

SoheeBut when the mother was present, the pups actually preferred the odor, despite the shock, and there was no increase in amygdala activation. The mother's presence changed whether they learned fear or attraction.

RyanEarly adversity matters too. In one rat study, pups given abusive treatment early in life were much more likely to show depressive-like behavior in adolescence than controls, and that behavior was associated with increased amygdala activation.

SoheeIn humans, changes in amygdala structure and function have been shown in adolescents who are at risk for, or diagnosed with, mood or anxiety disorders. And it's been suggested that functional differences in the amygdala could serve as a biomarker to tell bipolar disorder from major depressive disorder.

RyanThe hippocampus is involved in emotional processing as well. People with posttraumatic stress disorder show marked reductions in the volume of several parts of the hippocampus, which may result from decreased generation of new neurons and new dendrites.

SoheeAnd here's the careful part. That's correlational, so no causal claim. But studies have shown behavioral improvement and increases in hippocampal volume after either medication or cognitive-behavioral therapy for PTSD.

RyanNow back to Ekman. Despite different cultural display rules, our ability to recognize and produce facial expressions of emotion appears to be universal.

SoheeOne striking piece of evidence: even congenitally blind people produce the same facial expressions, though they've never been able to see anyone else make them.

RyanAnd the idea isn't new. Charles Darwin suggested it in the late nineteenth century, in his 1872 book on the expression of emotions in man and animals.

SoheeThe textbook says there's substantial evidence for seven universal emotions, each with a distinct facial expression, citing Ekman and Keltner. Happiness, surprise, sadness, fright, disgust, contempt and anger.

RyanSeven, in the textbook's list. Contempt is the one that's easy to leave out, so say all seven out loud once.

SoheeBut universal production doesn't mean universal display. A cultural display rule is one of a set of culturally specific standards governing which emotional displays are acceptable, and how often.

RyanFor example, research found people from the United States expressed negative emotions like fear, anger and disgust both alone and with others, while Japanese individuals did so only when alone.

SoheeAnd people from cultures that emphasize social cohesion are more likely to suppress emotional reactions, so they can judge which response is most appropriate in context. And on gender, research into differences in emotional display is equivocal, though there's some evidence that people of different genders may differ in how they regulate emotions.

RyanPause and think. Two students, one raised in a culture that emphasizes group harmony, watch an upsetting film, first alone and then with a professor in the room. One shows the same expression both times. The other shows distress only when alone. What concept explains the difference?

SoheeCultural display rules. The underlying expressions are universal, but culture governs when it's acceptable to show them.

RyanAnd emotion isn't only on the face. We communicate it through tone of voice, behaviors and body language, the expression of emotion through body position or movement. Research suggests we're quite sensitive to emotional body language, even when we're not consciously aware of it.

SoheeNow a classic applied question: the polygraph, or lie detector. It measures physiological arousal while someone answers a series of questions, on the assumption that most of us would show arousal when being dishonest.

RyanBut the textbook is blunt. Polygraphs are still commonly used, but their validity and accuracy are highly questionable, because there's no evidence that lying is associated with any particular pattern of physiological arousal.

SoheeSo the tempting wrong answer says the polygraph detects lies. What it detects is arousal, and arousal isn't specific to lying.

RyanLast, emotion regulation: how people respond to situations by modifying their emotional experiences and expressions. Covert strategies happen within the person. Overt strategies involve other people or actions, like seeking advice, or drinking alcohol.

SoheeAldao and Dixon studied two hundred eighteen undergraduates and found overt emotion regulation strategies were better predictors of psychopathology than covert ones.

RyanAnd much regulation happens without thinking. Mauss and colleagues studied automatic emotion regulation, the non-deliberate control of emotions. It can affect what you attend to, how you appraise, whether you engage in an emotional experience, and what you do afterward.

SoheeThe textbook compares it to riding a bicycle. Once you develop the process, you do it without thinking. And it can be adaptive or maladaptive.

RyanAdaptive automatic regulation leads to better health outcomes, mainly because people handle stressors better. Maladaptive patterns may be critical in maintaining some psychological disorders. And Mauss and colleagues found strategies that could reduce negative emotions.

SoheeSo, exam angles. Emotion versus mood. Basolateral complex versus central nucleus. Seven universal expressions, including contempt. Universal expressions versus culture-specific display rules. And polygraphs measure arousal, not lies.

RyanLet's recap. Emotion is intense, brief and tied to an event. Mood is prolonged, less intense and not tied to an event.

SoheeThe limbic system: hypothalamus for sympathetic activation, thalamus as relay, amygdala for emotional processing, hippocampus linking emotion and cognition.

RyanIn the amygdala, the basolateral complex is critical for classical conditioning, and the central nucleus regulates autonomic and endocrine activity. Context and early experience shape what it learns.

SoheeEkman: facial expressions of emotion appear universal, an idea Darwin suggested back in 1872. Seven universal emotions in the textbook's list, produced even by congenitally blind people. Display rules govern when they're shown.

RyanPolygraph validity is highly questionable. And emotion regulation can be covert or overt, deliberate or automatic, adaptive or maladaptive.

SoheeOne last thought. Emotion regulation is a skill, and skills can be built. If this exam brings up big feelings, that's human. Notice them, name them, and keep going at your own pace.

RyanTry a few practice questions, and we'll see you next time on EPPP Prep.

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