What is an Emotion?

Even though the term "emotion" is used very frequently, thequestion "What is an emotion?" rarely generates the same answer from different individuals, scientists or laymen alike.

Content

• Basic Concepts
• Theories of Emotions
• Measurement
• Affective Neuroscience
• Neuropsychiatry

Basic Concepts and Definitions

• Emotions entail psychophysiological states which results from conscious or unconscious processing or interpretation.
• Emotions can lead to reactions on situations or objects (emotional reaction).
• Emotions are associated to changes in physiological arousal, cognition, feelings and behavioral readiness.
• Disturbances are prevalent in mental disorders.
• Brandstätter et al. (2013): Emotions comprise subjectively experienced and objectively measurable components, fostering behaviour which enables humans to adapt to various conditions of life.

First-person perspective (subjective experience)

Feelings: subjective experiences of emotions (i.e., love, sadness, anger, joy) Feelings tend to be assessed by questionnaire measures.

Third-person perspective (objective)

• Physiological response: e.g., heart-rate variability, skin conductance, neural response.
• Behavioral response: e.g., fight or flight, laughter, crying, ...
• Such responses can be measured using objective measurements

The association between these levels of investigation is not always clear.

Emotions: Function

• Regulation of organismic states
• Preparation for action readiness & actions
• Signalling function (of subjective states and intentions)
• Biologically: emotions allow to recognize emotions relevant reproductive success and survival
• Distinctions:
  • Feelings: subjective experience/properties/instances of emotions
  • Mood: longer-lasting, usually lower level and diffuse
  • Affect: emotional condition/feeling states (incl. emotions/mood)
  • Emotions: targeted, usually clearly recognizable and often cause for actions (more short-term)

Emotions include interpretation of physiological responses and predictions based on prior experiences which cause actions and serve to regulate our body.

The brain remains a single part of an entire organism and is in constant interaction with all other body systems. This system adapts to the context we experience - for better or for worse.

Theories of Emotions

Various different theories about emotions exist, there is no such thing as "the one singular and definite emotion theory"

• Each theory stresses certain aspects of emotions
• Theories are affected by researchers' beliefs about human beings, theoretical assumptions and methodological expertise. Two predominantly discussed viewpoints:
• Dimensional perspectives: emotional states are organised by underlying factors such as valence, arousal, and motivational state.
• Discrete emotion perspectives, by contrast, suggest that each emotion (e.g., anger, sadness, happiness) has unique experiential, physiological and behavioral correlates.

Evolutionary Theories of Emotions

• Charles Darwin, 1872: “The expression of the emotions in man and animals”
• Emotional expressions were originally linked to a specific purpose.
• Facial expressions eventually automatized.
• Emotions result from the evolution of humans and animals.
• Function of emotions are either organismic or communicative function.
• Emotions serve to increase our chances of survival.
• Darwin observed facial expressions in humans and animals in order to prove his theory that humans descended from animals. He argued that all humans and animals show emotion through remarkably similar behaviors. They are assumed as discrete and linked to specific emotional expressions (face, gesture, posture). (Debunked)
  • Methods: observation and comparison of expressions between human and animals, within and between cultures, children, blind humans, psychiatric patients.
  • Critique: small samples, indirect assessments of other cultures, leading questions.

Behavioristic Theories of Emotions

• Behaviorism theories assume that human and animal behavior is explained by conditioning.
• Classical Conditioning (Pavlov): in simple terms, two stimuli are linked together to produce a new learned response in a person or animal. Following Pavlov, John Watson later proposed that the process of classical conditioning (based on Pavlov's observations) was able to explain all aspects of human psychology.
• Behaviorism denies introspection or concepts like "perception", "intention", "thinking" and "emotion"
  • Emotion = an objective, observable (heritable) reaction pattern which is solidly evoked by specific stimuli.
  • Emotions are profound changes in an organism putting it into a state of chaos.
  • Emotions are not advantageous for biological fitness.
• John B. Watson (1878-1958): "Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select ... regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors."
  • Only three heritable reaction patterns ("emotions") exist: Fear, Anger and Love.
  • "Pure emotions" exist in new-borns only.
  • Children and adults: various evoking stimuli and different emotions exist due to learning (classical conditioning).
• Classical Conditioning (Little Albert): Watson and Rayner planned to condition a phobia in an emotionally stable child. How classical conditioning can be used to condition an emotional response.
  • Neutral Stimulus: a stimulus that does not initially elicit a response (the white rat).
  • Unconditioned Stimulus: a stimulus that elicits a reflexive response (the loud noise).
  • Conditioned Stimulus: a stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus (the white rat).
  • Conditioned Response: the response caused by the conditioned stimulus (fear).

• Edward Thorndike (1874 - 1949)
  • Animal studies
  • Puzzle boxes
  • The animal would be required to perform a certain response (pulling a lever or pushing a button) to escape.
  • Developed the concept of instrumental/operant conditioning
  • Mainly used data from animal-based experimentation (similar to Pavlov)

• Burrhus Frederic Skinner (1904-1990)
  • Principle of reinforcement: action is dependent on the consequences of previous actions.
  • If the consequences to an action are bad, there is a high chance the action will not be repeated; if the consequences are good, the probability of the action being repeated becomes stronger.

• Implications: Desensitization
  • If the majority of emotional responses are learnt, then they can consequently be unlearnt again (e.g., therapy, desensibilisation, etc.)
  • Traumas, therapy, ... (Resilience describes our ability to bounce back from negative and adverse situations of experiences and overcome the negative associations attached to these).

Physiological Theories of Emotions

Responses within the body are responsible for emotions.

• Paul Ekman: Neuro-Cultural Theory on Emotions (1969)
  • Certain human emotions are universal, but facial expression of these emotions can be influenced by social/cultural learning.
  • Strongly influenced by Darwin's ideas:
    • Seven basic emotions have evolved with natural selection: anger, disgust, fear, happiness, sadness, surprise, contempt.
    • Each emotion is linked to a specific feeling, a specifical physiological change (therefore "neuro"-cultural) and a specific mimic expression.
    • Tendency to show a specific facial expression are hereditary but can be adapted deliberately.
    • With socialisation more control of facial expression, due to display rules: intensify, mitigate, neutralize, mask.
  • Critique:
    • Measurement (different basic emotions are chosen by researchers)
    • The term "basic emotions" differentiates such emotions as fundamentally different from other emotions (assumption of pure emotions that make up all others. However, emotions are often a mix).
    • Dimensional theories assume emotions on a different spectrum: e.g., based on valence (desire - reluctance), arousal (from hyper- to hypo-arousal), etc.

James-Lange Theory (1922)

• Emotions are the result of physical changes in the body. According to James and Lange, our body's responses to an emotional event - such as a racing heart rate or sweating, for example - are what make up our emotional experience.
• Critique:
  • Similar autonomic reactions are caused by different emotional states (i.e., anger or fear)
  • Similar autonomic reactions can be caused by non-emotional states (for example due to exercise or temperature, e.g., heart rate / sweating)
  • Internal organs are relatively insensitive (slow information detection)
  • Patients with spinal cord injuries still experience emotions.

Cannon-Bard Theory (1931)

Schachter & Singer (1962)

Dodge's Social Processing Theory (1994): Cognition and Development

• The social information processing theory focuses on how children process experiences. An example is a child who has been pushed in line at school. They may assume the other child did it intentionally or as an accident. How the child interprets the interaction will shape how the child will respond.
• The SIP model suggests that children enter social situations with a database of predetermined influences from biologically determined capabilities along with the set of experiences (and the memory of those experiences) that the child has had (Crick & Dodge, 1994).

The Concept of Emotion Socialization

• "Emotion socialization" conveys the essential idea that children learn to understand, express and self-regulate emotions in social contexts.

The Modal Model of Emotion: James Gross (1998)

• The modal model of emotion suggests that the emotion generation process occurs in a particular sequence over time:
  • Situation: emotionally relevant situation (real or imagined)
  • Attention: attention is directed towards the emotional situation.
  • Appraisal: the emotional situation is evaluated and interpreted.
  • Response: an emotional response is generated, giving rise to different response systems.

The Process Model of Emotion Regulation: James Gross (1998)

• Gross (2001) defines emotion regulation as "all of the conscious and nonconscious strategies we use to increase, maintain, or decrease one or more components of an emotional response."
• Process model of emotion regulation (Gross, 1998):
  • Four different types of antecedent-focused emotion regulation strategies, which can be applied at different points in the process of emotion generation:
    • Situation selection
    • Situation modification
    • Attentional deployment
    • Cognitive change
    • A fifth, response-focused strategy: response modulation

Measurement

Emotion Classification

From two fundamental view-points:

• Categoric/Discrete
• Dimensional

Subjective Experience: Self-reports of Emotion

• More valid to the extent that they relate to currently experienced emotions.
• Concerns: not all individuals are aware of and/or capable of reporting on their momentary emotional state.
• Dimensional frameworks, relative to discrete ones, better capture this measure of emotion.

Peripheral Physiology: Autonomic Measures of Emotion

• The autonomic nervous system (ANS) is a general-purpose physiological system responsible for modulating peripheral functions.
• Consists of sympathetic and parasympathetic branches, which are generally associated with activation and relaxation.
• General-purpose: ANS activity relating to digestion, homeostasis, effort, attention, and so forth -> important because it is often not clear whether activity in the ANS reflects emotional processes or other ANS functions.
  • Electrodermal (i.e., sweat-gland): skin conductance level (SCL) or short-duration skin conductance responses (SCRs).
  • Cardiovascular (i.e., blood circulatory system): heart rate (HR), blood pressure (BP), total peripheral resistance (TPR), cardiac output (CO), pre-ejection period (PEP), and heart rate variability (HRV).

Affect Modulated Startle: Startle Response Magnitude

• Startle in response to a sudden, intense stimulus is a universal reflex that involves multiple motor actions, including tensing of the neck and back muscles and an eye blink - Landis & Hunt, 1939.
• Protective function, guarding against potential bodily injury.
• Amygdala, centrally involved in vigilance and threat detection, is a key for modulating the startle response.
• Marker of the valence dimension of emotional states.
• Larger in the context of high-arousal negative stimuli and reliably smaller in the context of high-arousal positive stimuli.
• Does not appear to assess discrete emotional states.
• Reflex Modulation: amygdala, bed nucleus of the stria terminalis (BNST) and anterior cingulate cortex.

Central Physiology: Brain States as a Measure of Emotion

• Following Cannon & Bard and other cognitive theorists emotions were suggested to more likely be reflected in brain responses rather than through the autonomic nervous system.
• Testing for example by EEG or fMRI.
• EEG
  • Excellent temporal resolution, lower spatial resolution.
  • Typically contrast activation in fairly large regions of the brain.
• Model of Frontal Asymmetry
  • Approach-related states: relative left-hemisphere activation
  • Avoidance-related states: relative right-hemisphere activation

• (f)MRI
  • Brain activity measure by detecting changes associated with blood flow.
  • Cerebral blood flow and neuronal activation are coupled. Brain activation -> blood flow increases.
  • Blood-oxygen-level dependent (BOLD) contrast.
  • High-spatial resolution (measured in voxel), medium temporal resolution

Behaviour as Measures of Emotion

Darwin (1965): emotions serve an evolved communicative function, thus resulting in behaviours that reveal one's emotional state to others (Darwin, Ekman) -> possibility to infer a person's emotional state from vocal characteristics, facial displays, and whole-body behaviours.

• Vocal Pitch
  • To assess the level of emotional arousal
  • difficult to find vocal characteristics that are sensitive to valence (e.g., anger and joy are similar in emotional arousal, but different in valence, yet both emotions have been linked to comparable vocal pitch and vocal amplitude).
  • Banse and Scherer (1996): tested relations between 14 emotion inductions and 29 acoustic variables: combining ten acoustic properties differentiated discrete emotions to a greater extent than could be attributed to valence and arousal alone.
• Facial Behavior - Facial Action Coding System (FACS)
  • Facial behaviour is coded using componential coding: trained coders detect facial muscle movements (or "facial actions") using reliable scoring protocols:
    • anatomically based system that assesses 44 different muscle movements.
    • Facial behaviours appear to reliably indicate the valence of a person's emotional state.
    • Emotion specificity of facial behaviour is problematic (few studies exist).
    • Facial electromyography (EMG): measures electrical potential from facial muscles via electrodes on the face.

Measures of Emotions

• Dimensional perspectives: emotional states are organised by underlying factors such as valence, arousal, and motivational state.
• Discrete: emotion perspectives, by contrast, suggest that each emotion (e.g., anger, sadness, happiness) has unique experiential, physiological, and behavioural correlates.
• Measures of emotional responding appear to be structured along dimensions (e.g., valence, arousal) rather than discrete emotional states (e.g., sadness, fear, anger)
• Different measures of emotion appear sensitive to different dimensional aspects of state (e.g., facial EMG is more sensitive to valence, skin conductance more to arousal) and are not strongly related to one another.
• No "gold standard" measure of emotional responding. Emotions are constituted by multiple, situationally and individually variable processes.

Affective Neuroscience

Stimuli

• Images, sounds, movies, combination of stimuli
• International Affective Picture System (IAPS)
• International Affective Digitized Sounds (IADS)
• Bradley & Lange, 2000
• Biological Motion and Emotions from Point-Light Displays

Naturalistic Movie Clips

Pros for the use of naturalistic movie-clips:

• Rich anatomical and functional data sets in younger individuals are possible
• recognized in existing paediatric neuroimaging protocols
• movie-based designs reduce head motion artefacts (common & propagated in functional connectivity analyses)
• naturalistic property (multilayer-composition mirroring the complexity of human experiences)
• High-analytical flexibility
• The signal complexity under naturalistic conditions + intrinsic functional connectivity patterns
• Highly promising to inform developmental neuroscience in children.

Papez Circle (James Papez, 1937)

• Historical Accounts: brain research attempted to identify areas related to emotion generation and regulation -> Papez circle.
• “The hypothalamus, the anterior thalamic nucleus, the cingulate gyrus, the hippocampus and their interconnections, constitute a harmonious mechanism which may elaborate the functions of central emotion as well as participate in the emotional expression." - James Papez, 1937

Limbic System

The limbic system consists of the phylogenetically old limbic lobe and other subcortical structures and their connections. Although not empirically proven, the limbic system is a functional concept which continues to be employed to explain various brain functions. To date, it is assumed to contain both, subcortical and neocortical brain regions.

Emotions are not simply reactive or formed in an ancient animalistic part of our brains (Lizard Brain, Debunked).

Brain & Emotions

• Complex reactions (e.g., emotional states) linked to circuits rather than any isolated brain region.
• Some play a relatively greater or lesser role within larger circuits; thus localisation studies identify key regions.
• *Amygdala & Fear
  • Commonly identified during negative affect or fear processing.
  • Amygdala is particularly responsive o fearful images relative to other fear-induction methods
  • Bilateral amygdala damage: reduced, but possible, fear learning and processing (it's not just a/or the single fear processing center) (Debunked)
  • Today: amygdala may be core to valence evaluation (no matter what emotions).

Brain States as a Measure of Emotion: fMRI

• Disgust & Insula:
  • Wide variety of negative emotion inductions activate the insula.
  • The insula supports many other psychological functions (e.g., taste, implicit learning, procedural memory, motor performance. The sole structure-function associations are mostly debunked).
• Sadness: medial prefrontal cortex (mPFC) and anterior cingulate cortex (AC):
  • Potential confound: induction methods involve high cognitive demand (e.g., recalling a past event that caused sadness).
  • Cognitively demanding emotion inductions activate rostral portions of the ACC to a greater extent than passive emotional processing. Importance in the process, yes, but sole structure-function association is debunked.
• Meta-analyses provide support for a dimensional perspective on emotion and brain activity.
• Specific brain regions link to states of approach and avoidance.
• Since emotional states are complex involving circuits, neuroimaging methods that examine interrelated activity among multiple brain regions may hold promise for understanding whether and how emotional specificity is instantiated in the brain (Mauss & Robinson, 2009).
• Towards an integrated understanding of the human affectome (Lowe et al): produce a series of overarching reviews that can summarize much of what is currently known about affective neuroscience while simultaneously exploring the language that we use to convey feelings and emotions.

Neural Model of Emotion Regulation (Cognitive Reappraisal) (Kohn et al., 2014)

Recent studies on the neural correlates of explicit emotion regulation

Neuropsychiatry

Disorders of Emotion Processing and Regulation

Conduct Disorder (CD) is a mental disorder of childhood and adolescence and is characterized by severe antisocial and aggressive behaviors.

• Diagnosed before the age of 18.
• Age-inappropriate
• More common in boys
• Until recently it was almost exclusively described based on studies in males.
• Proficient emotion regulation is typically attained in late adolescence or early adulthood.
• Linked to better social functioning, psychological and physical health.
• Deficient emotion regulation is associated with childhood psychopathologies, including CD.

Background

Emotion regulation skills provide a means of controlling the intensity, duration, or extent of the experience evoked by an emotional stimulus or situation.

Neural Correlates (ER)

Goal: an increased understanding of the underlying mechanisms, of protective and/or risk factors leading to typical and atypical brain or behavioral development (i.e., emotion regulation skills) may add to our understanding of affective disorders, including those in childhood and adolescents, possibly informing diagnosis and treatment.

Summary and Conclusions

• While definitions vary, theories reflecting historic/present understanding. Still, our emotions are at the core of our social life and everyday well-being.
• Experiences are processed by the brain and affect it. They determine our future expectancies and actions.
• Early life: sensitivity to input across maturation.
• The generation, perception and regulation of emotions is likely performed by the dynamic interplay of different larger-scale neural networks.
• Our brains are a result of ongoing adaptation processes. As such emotions are a construct and do not just happen to us.
• Affective Neuroscience aims to understand such mechanisms to support individual needs.

You are an architect of your emotions. Your present emotions are a construct, a prediction, of your brain and it is based on prior experiences. This implies that you can break a pattern - Lisa Feldmann Barrett.