Emotion, Lecture 6 Flashcards
Darwin and Emotional Expressions
Darwin proposed that many species of animals, including humans, communicate through changes in posture, facial expression, and nonverbal sounds.
Emotional expressions are innate and biologically determined, according to Darwin’s theory (1872).
Darwin made observations of his own children and corresponded with people in isolated cultures around the world to support his theory.
Basic Emotions Theory by Ekman
Ekman’s Basic Emotions Theory suggests that basic emotions are associated with distinctive facial expressions, voice intonation, body movement, and distinct neural substrates.
Each emotion has evolved to deal with different survival problems and occurs automatically.
According to this theory, there are six basic emotions: sadness, happiness, disgust, surprise, anger, and fear.
These emotions are universal and mostly culture-independent.
Cross-Cultural Studies of Emotion
Ekman and Friesen (1971) conducted a study to investigate if members of an isolated tribe in New Guinea could recognize facial expressions of emotion produced by Westerners.
Results showed that people in the New Guinea tribe could recognize western emotional expressions.
Ekman, Sorenson, and Friesen (1969) conducted another study to investigate if Westerners could recognize emotion expressions of different cultures.
Results showed that Westerners could recognize these expressions.
The conclusions drawn from these studies indicate that the expression of emotions is unlearned as they are the same in cultures that have not been exposed to each other.
James-Lange Theory
The James-Lange Theory suggests that emotion-producing situations elicit physiological responses such as trembling, sweating, and heart pounding.
Certain behaviors may also be exhibited, such as running away or feeling queasy.
The feedback from the organs and muscles involved in these responses constitutes how we feel emotion, which determines our own emotional feelings based on what we find ourselves in.
Cannon-Bard Theory
The Cannon-Bard Theory proposes that the thalamus sends simultaneous signals to the cortex (for conscious experience) and the autonomic nervous system (for arousal) in response to an emotion-producing stimulus.
According to this theory, emotions do not arise solely from bodily reactions, but rather from both physiological and cognitive processes occurring simultaneously.
Somatic Marker Hypothesis by Damasio
The Somatic Marker Hypothesis suggests that bodily states are the basis of emotions and decisions.
A threatening stimulus can instinctively generate a physiological response, such as an accelerated heartbeat, which sends interoceptive signals to the brain.
These signals are experienced as somatic markers, which mark the emotional value of stimuli and events and facilitate decision-making, particularly in ambiguous situations.
Theory of Constructed Emotions by Feldman-Barret
The Theory of Constructed Emotions proposes that there are no distinct emotional categories, and the emotions we feel are constructed based on the current situation and our previous experiences.
Emotions depend on core affect, memory of previous similar situations, theory of mind, language, and assumed control over the situation and emotions.
According to this theory, all emotions are constructed, and facial expressions cannot be innate either.
Basic Emotions Theory vs. Theory of Constructed Emotions
The Basic Emotions Theory (BET) proposes that facial expressions are innate for basic emotion categories.
The Theory of Constructed Emotions (TCE) proposes that all emotions are constructed, and facial expressions cannot be innate either.
BET acknowledges that some emotions might be constructed, while TCE argues that all emotions are constructed.
Overall, these two theories offer different perspectives on the nature of emotions and how they are generated in the human body and mind.
Amygdala Overview
The amygdala is a small mass of gray matter located in the tip of the left and right temporal lobes. It receives a great deal of sensory input and is often referred to as the “fear center” of the brain. The amygdala plays an important role in learning and storing the emotional value of stimuli.
Fear Conditioning and Amygdala
The amygdala plays a critical role in fear conditioning, in which meaningless stimuli come to acquire fear-inducing properties. If the amygdala is lesioned before learning, the animal does not learn the conditioned response. However, if the amygdala is lesioned after learning, the animal forgets the conditioned response, and objects lose their learned emotional value.
Amygdala and Memory
The amygdala is also important for learning and storing conditioned fear response in memory. However, normal fear-evoking stimuli can still elicit a fear response, indicating the amygdala’s role in learned fear responses.
Amygdala and Fear Recognition
Bilateral amygdala damage impairs the recognition of fear expression in faces. In an fMRI study, participants presented with fearful faces showed left amygdala activity, while different brain areas were activated in response to happy faces.
Amygdala Activation without Conscious Awareness
The amygdala can be activated without conscious awareness through fast and slow routes to the amygdala. Studies have shown that images of spiders and snakes presented subliminally can evoke emotional responses, as measured by skin conductance response, even when participants do not report seeing the images.
Amygdala and the Wider Fear Network
Amygdala activity can lead to enhanced activity in other brain areas, including the visual cortex, hypothalamus, anterior cingulate, and orbitofrontal cortex. This affects the autonomic system, leading to the generation of a fight or flight response.
Amygdala and Positive Associations
The amygdala is involved in learning positive associations, such as when a certain food is hidden under a certain shape. The amygdala also shows activation in response to pleasant and unpleasant smells, but not neutral smells.
Insula
Location: An island of cortex located bilaterally underneath the temporal lobes.
Function: Implicated in the creation of bodily feelings associated with emotions, particularly disgust and interoception.
Insula & Disgust:
Insula lesions affect disgust perception (Calder et al., 2000).
Insula activation occurs when feeling disgusted or seeing someone else disgusted (Wicker et al., 2003).
Moral disgust also activates insula.
Insula and interoception:
Interoception is monitoring the internal state of the body.
Interoceptive signals from receptors in the skin, muscles, and organs are sent to the brain (insula) along the spinal cord.
Bodily changes play an important role in emotions according to several theories, including the James-Lange Theory, Somatic Marker Hypothesis, and Theory of Constructed Emotions.
Orbitofrontal Cortex
Computing the current value of a stimulus – how rewarding the stimulus is within the current context. Important for social interactions, new learning, and regulation of emotions.
Orbitofrontal Cortex (OFC) – reward and punishment:
PET study (Small et al., 2001):
Initially, chocolate was rewarding, and participants wanted to have it – activity in the medial regions of the OFC = pleasant, reward.
Then, chocolate became less pleasant, and participants were less motivated to eat it – activity in the lateral regions of the OFC = unpleasant, punishment.
OFC also involved in regulating reward-guided behavior.
Orbitofrontal Cortex (OFC) – social stimuli:
Lateral OFC activity when presented with an unexpected angry face instead of an expected smile (Kringelbach & Rolls, 2003).
OFC plays a role in social emotions such as empathy, social decision-making, and moral judgments.
Anterior Cingulate Cortex (ACC) and Executive Functions
The anterior cingulate cortex is located above the corpus callosum on the medial surface of each hemisphere.
The dorsal region of the ACC is implicated in executive functions.
Executive functions include motivation, determining the cost and benefit of actions, and evaluating the value of a response.
Anterior Cingulate Cortex (ACC) and Emotional Processing
The ventral region of the ACC is implicated in emotional processing.
The ACC processes bodily signals that characterize emotions, which are input from the insula.
A lesion in the ACC can interrupt skin conductance response, changes in blood pressure and heart rate.
The ACC regulates feelings of pain and responds to physical pain as well as the perception of pain in others.
Anterior Cingulate Cortex (ACC) and Pain Perception
A study by Singer et al. (2004) found that the ACC responds to physical pain and social pain.
The ACC activity is correlated with subjective distress.
The perception of pain in others can be affected by cognitive processes, and the ACC response can be modulated if the other person is perceived to “deserve” the pain.
Anterior Cingulate Cortex (ACC) and Social Exclusion
A study by Eisenberger et al. (2003) used a virtual ball-tossing game to investigate social exclusion.
The study found that the ACC activity was correlated with subjective distress in the three conditions of inclusion, exclusion, and justified exclusion.
The ACC response to the reception of pain in others can be affected by cognitive processes, such as the perceived justification for the pain.
Ventral Striatum
Part of the basal ganglia and specializes in emotions
Involved in reward-based learning loop ‘the limbic circuit’
Dopaminergic system linked to compulsive behaviors like substance abuse
Shows greater activity in fMRI tasks with monetary rewards and social rewards obtained through cooperation with humans (Knutson et al., 2001; Rilling et al., 2002)
Activity is greater when reward is better than expected
Autism Spectrum Disorder (ASD):
Persistent deficits in social communication and interaction, and repetitive behaviors and interests
Symptoms present in early childhood, limit and impair everyday functioning
“Social brain” network, including ventral striatum, orbitofrontal cortex, and amygdala, has functional and/or structural differences in ASD
Social Motivation Hypothesis:
Children with ASD have deficits in representing the reward value of social stimuli
They do not actively attend to the social environment because they do not find it intrinsically rewarding
This leads to reduced cortical specialization, reduced seeking and liking of social interactions, and ultimately global deficits in social functioning
Mixed evidence for the hypothesis exists (meta-analysis: Bottini, 2018)
