Lecture 3: Theories of Emotion CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Affective Computing in the news Dacher Keltner Berkeley CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Outline Review why emotion theory useful – Give some positive and negative examples Introduce some features that distinguish different theories – – – Emotions as discrete or continuous Emotions as “atoms”, “molecules”, or “mxtures” Emotions as a consequence or antecedent of emotion Review some specific influential theories In-class “experiment” (3-unit students welcome to depart) CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Why should we care about emotion theory? CSCI 534(Affective Computing) – Lecture by Jonathan Gratch What is a Theory Theory explains how some aspect of human behavior or performance is organized. It thus enables us to make predictions about that behavior. – Provides a set of interrelated concepts, definitions, and propositions that explains or predicts aspects of human behavior by specifying relations among variables. – Allows us to explain what we see and to figure out how to bring about change. – Is a tool that enables us to identify a problem and to plan a means for altering the situation. – Create a basis for future research. Researchers use theories to form hypotheses that can then be tested. – Creates a basis for building software: suggests what variables are important to measure and how they relate to each other CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Does a learned model count as a theory? We’ll learn about machine learning approaches – – Collect bunch of data Look at lots of features and try to predict some outcome Input Features (events in a video game) Allow us to make predictions? – Give insight into underlying mechanism? – Yes Not typically (black box). But can answer what features are relevant Indicate how to bring about change? – Not typically CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Predicted output And can be misleading: Famous example In ‘80s, the Pentagon wanted to harness computer technology to make their tanks harder to attack. The research team went out and took 100 photographs of tanks hiding behind trees, and then took 100 photographs of trees - with no tanks. They trained a neural network. It reached near-perfect accuracy Independent testing showed all “no tank” photos taken on sunny day and all “tank” photos taken on cloudy day Because neural network was “black box”, this not easy to discover CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Affective Computing Example Last week, showed you system that tries to recognize nonverbal signs of depression and PTSD We collected data from two populations tIn – Craigslist (and online job-recruiting service) – US Vets: organization that provides mental-health service for former soldiers Tried machine learning approach Discovered vocal pitch a strong predictor of depression – Lower pitch predicted depression severity – Not predicted by existing theory Turns out there was big imbalance in our data – US Vets had highest rates of depression – US Vets also had highest rates of Males (most soldiers are male) – We actually “discovered” that men speak with a lower pitch CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Advantages of building on theory Theory makes explicit the mechanisms that (are claimed to) underlie some behavior – Allows us to explain what we see and to figure out how to bring about change Theories (typical) have good empirical support – The theories we will discuss are supported by dozens of empirical studies – They may still be incorrect of insufficient but are unlikely to suffer the sort of mistakes we just discussed CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Example: Appraisal Theory Mental State World Events Argues for importance of three interrelated concepts • World events • Mental state (e.g. goals) • Emotional Response (beliefs, goals) Body Expression If we know two of these variables, we can make predictions about the third Response= f(Env., Mind) Action Tendency Physiological Response 10 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch E.G.: Generating Emotional Response R=f(E,M) Beliefs, Goals Environment COMPUTER PREDICITONS: Emotional Response Expression Action Tendency Physiological Response • Computer could predict what emotion a person might hold • Computer could generate a believable emotion to user 11 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch E.G.: inferring emotional antecedents M=f-1(E,R) Reverse Appraisal Beliefs, Goals Environment COMPUTER PREDICITONS: Emotional Response Expression Action Tendency • Computer could predict what goal person has (i.e., what team are they rooting for Physiological Response 12 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Influential theory: Galen’s 4-process model of emotion “Arousal” Posits 4 “prototypical emotions”. Emotions organized in 2-dimensional space (valence, arousal) Argues emotions tend to transition along arrows. “Angry” “Happy” “Sad” “Apathetic” “Valence” CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Galen’s 4-process model of emotion Prototypical emotions associated with 4 specific physiological systems “Arousal” YB Bl “Angry” “Happy” BB Ph “Apathetic” “Sad” “Valence” CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Popular 2-dimensional model of emotion Each prototypical state associated with a characteristic expression YB Bl “Arousal” C S Angry BB Happy Ph M P Sad “Valence” CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Apathetic Again, this theory affords implementation and prediction YB Dimension 1 – 4 “prototypical” emotion labels but – 2 dimensions Bl C S Angry Happy BB Ph M Recognition “language” Predictions – If we recognize Anger expect YB is active – If recognized Anger, don’t expect transition to Apathy – If BB active, expect sad expressions and selfreport of Sadness P Apathetic Sad Dimension 2 Control – Can create Apathy by activating Ph system or suppressing other systems – Can’t control Ph by activating Apathy CSCI 534(Affective Computing) – Lecture by Jonathan Gratch A Hippocratic physician would prescribe treatment to void the body of imbalanced humor. if it was a fever -- a hot, dry disease -the culprit was yellow bile or blood. So, the doctor could reduce this by, e.g., bleeding the patient, or increase its opposite, by Galen of Pergamun (c. 180AD) phlegm, by prescribing cold baths. Theory of the Four Humours Temperature Hot (Fire) Yellow Bile Blood Choleric Black Bile Sanguine Phlegm Melancholy Phlegmatic Cold (Air) Dry (Earth) Wetness CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Wet (Water) Proof of the Theory of the Four Humours by Galen of Pergamun (c. 180AD) 1793 an epidemic of yellow fever struck Philadelphia Benjamin Rush (signer of Declaration of Independence) treated by vigorous bloodletting Each patient that recovered and survived served to prove the theory Each patient that died confirmed that the patient was too ill for the treatment to work Any issue with this? – Example of confirmation bias: a common decision-making bias – Another example: “proof that aliens have landed on earth” CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Falsifiability A good theory is falsifiable – Falsifiability or refutability of a theory is an inherent possibility to prove it to be false. – Theories that are so vague they can explain anything (ex. Psychic readings) are not falsifiable – The more specific a theory it is, the more likely it is falsifiable Karl Popper: on falsifiability, testability Galen’s theory is falsifiable (and has be falsified) ‘What characterises the empirical method its manner of – Even if Benjamin Rush failed to test it is properly exposing to falsification, in every conceivable way, the system to be tested. Its aim is not to save the lives of untenable systems but, on the contrary, to select the one which is by comparison the fittest, by exposing them all to the fiercest struggle for survival’ CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Why should we care about emotion theory Provides a definition of “emotion” and other related concepts that influence, or are influenced by emotion, and thus a starting point for affective computing Unfortunately, psychology hasn’t sorted it all out yet – Different theories suggest different concepts and relationships between them E.g., Say we want to recognize emotion – Give labeled data to machine learning algorithm – But what are the labels? Joy vs. Hope vs. Fear? Positive vs. Negative? Affective computing researchers must make educated guess about which theory to use – But their success or failure can inform research in the social sciences CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Affective computing is interdisciplinary science Theory • • • • e.g., Rapport (positive, Psychology contingent, nonverbal feedback) Linguistics facilitates conflict Neuroscience resolution Economics Data Human Behavior Embed capability within interactive virtual human testbed Rapport Integrated “Test bed” MRE SASO-ST Gunslinger DCAPS Rapport 21 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Affective computing is interdisciplinary science Inform theoretical debate in social science Verify Implementation • Consistent with prior findings? • Treated “as if” real Human Behavior Test theoretical predictions Human Studies Integrated “Test bed” MRE SASO-ST Gunslinger DCAPS Rapport 22 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch For us, A theory should answer “What is emotion?” Emotion is a feeling Emotion is a state (of physiological arousal) A brain process that computes the value of an experience --- Le Doux A word we assign to certain configuration of bodily states, thoughts, and situational factors – Feldman Barrett. God’s punishment for disobedience -- St Augustine CSCI 534(Affective Computing) – Lecture by Jonathan Gratch But also, what is emotion NOT? From Scherer (optional reading) CSCI 534(Affective Computing) – Lecture by Jonathan Gratch So what is the accepted theory of emotion? Unfortunately, none exists CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Why no grand unified theory of emotion? CSCI 534(Affective Computing) – Lecture by Jonathan Gratch What is an emotion? Components of emotion Emphasizes that emotion potentially impacts several aspects – Cognitive: influences or influenced by thinking – Physiological: related to hormones, heart-rate, sweating… – Expressive: relates to facial expressions, posture, vocal features – Motivation: relates to goals and drives – Feeling: relates to conscious awareness being in an emotional state CSCI 534(Affective Computing) – Lecture by Jonathan Gratch What is an emotion? Phases of emotion: Emphasizes that emotions have “stages” – – – – – – – Low-level: automatic cognitive processes (e.g., reflexes) Hi-level: deliberate, conscious cognitive processes Goals/need setting Examining action alternative: decision-making/action-selection Behavior preparation Behavior execution Communication with other CSCI 534(Affective Computing) – Lecture by Jonathan Gratch What is an emotion? Different theories emphasize different aspects: – Appraisal theories emphasize cognitive antecedents of emotion – Discrete emotion theories emphasize physiological and expressive consequences of emotion Affective computing researchers tend to draw on different theories depending on the aspects they focus on – E.g : emotion recognition techniques often draw upon discrete emotion theory and avoid appraisal models CSCI 534(Affective Computing) – Lecture by Jonathan Gratch What is an emotion: theoretical disagreements Different theories can be distinguished by how they chose to define emotion with respect to the previously-mentioned components and phases – Is emotion discrete or continuous? – Is emotion an “atom” or “molecule”? (Barrett) – Is emotion an antecedent or consequent of cognition? CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Emotions as discrete categories, biologically fixed, universal to all humans and many animals Emotions are a combination of several psychological dimensions Basic Emotions: Anger, disgust, fear, happiness, sadness, surprise Rene Decartes, Silvan Tomkins, Paul Ekman CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Wilhelm Wundt, James Russell, Lisa Feldman Barrett Emotions as discrete categories, biologically fixed, universal to all humans and many animals Emotions are a combination of several psychological dimensions Basic Emotions: Anger, disgust, fear, happiness, sadness, surprise Rene Decartes, Silvan Tomkins, Paul Ekman CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Wilhelm Wundt, James Russell, Lisa Feldman Barrett Some discrete emotion theories Tomkins – Excitement, joy, surprise, distress, anger, fear, shame, dissmell (reaction to bad smell), disgust (reaction to bad taste) Ekman – Sadness, happiness, anger, fear, disgust, and surprise, sometimes includes contempt E.g. Le Doux fear circuit CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Some Dimensional models Mania ↔ depression High self-control ↔ “letting go” Russell & Mehrabian’s ‘77 PAD model (pleasure, arousal, dominance) CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Russell’s ‘80 circumplex model Implications for classification / measurement Continuous CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Implications for classification / measurement Discrete Disgust Continuous Fear Surprise CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Atom Molecule or Mixture Emotion components are tightly-coupled and can be treated as a circuit linking stimuli and response Emotions are defined by loose configuration of different components Jaak Panksepp, Joseph LeDoux, Paul Ekman Phoebe Ellsworth, Klaus Scherer, Lisa Feldman Barrett CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Atom Molecule or Mixture Emotion components are tightly-coupled and can be treated as a circuit linking stimuli and response Emotions are defined by loose configuration of different components Jaak Panksepp, Joseph LeDoux, Paul Ekman Phoebe Ellsworth, Klaus Scherer, Lisa Feldman Barrett CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Implications for classification / measurement If emotion is atomic circuit, all components should be aligned – i.e., Facial expressions, physiological response and felt emotion should be consistently-aligned with each other – “Emotion” can refer to the overall circuit but can be measured by any of the components – Measured expressions should predict physiology and felt emotion – Multi-modal recognition should perform the best CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Implications for classification / measurement If emotion is atomic circuit, all components should be aligned – i.e., Facial expressions, physiological response and felt emotion should be consistently-aligned with each other – “Emotion” can refer to the overall circuit but can be measured by any of the components – Measured expressions should predict physiology and felt emotion – Multi-modal recognition should perform the best If emotion a molecule or mixture, components not aligned – Allow that components influence each other but may be out of sync – Expressions need not accurately reflect physiology and felt emotion – Constructivist Theories (Feldman Barrett): Emotion is a label we assign to our sensed physiological state – Appraisal theories (Scherer & Ellsworth): Emotion is a label a scientist might apply when different components align in a prototypical way CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Atom or Mixture Discrete: redundancy across channels – Multimodal should be strictly better than unimodal Predicted output CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Atom or Mixture Discrete: redundancy across channels – – Multimodal should be strictly better than unimodal Late fusion should be great Predicted output Mixture: not so fast… – Or at least, association between modalities and predicted emotion is complex CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Top down Behav. Drives emotion (e.g. Appraisal Theory) (e.g., constructivist theories) Thought precedes emotion. Emotion precedes and motivates behavior Behavioral response precedes our labelling the situation as emotional Walter Cannon, Phoebe Ellsworth, Klaus Scherer William James, Stanley Schachter, Lisa Feldman Barrett CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Top down Bottom up (e.g. Appraisal Theory) (e.g., constructivist theories) Thought precedes emotion. Emotion precedes and motivates behavior Behavior and body response precedes and motivates emotion and cognition Walter Cannon, Phoebe Ellsworth, Klaus Scherer William James, Stanley Schachter, Lisa Feldman Barrett CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Appraisal Theory “Bottom up” theories argue “seeing the bear” produces fear-like reactions automatically What if we knew the bear was friendly? What if we knew the bear was chained up? Magda Arnold CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Appraisal Theory Appraisal models emphasize the prior beliefs and goals determine shape emotional responses Explain this by arguing that cognitive processes ESSENTIAL in initiating emotional responses World events are “appraised” along a number of dimensions: – – – – Is the event good or bad with respect to my goals Did I expect the event Can I control the event Who do I blame for the event Different patterns of appraisal will lead to different emotions – I blame someone else for something bad Anger CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Some Appraisal Theories Ortony, Clore and Collins (OCC) Appraisal Variables • desirability •appealingness •praiseworthyness •certainty CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Some Appraisal Models Scherer sequential checking theory Appraisal Variables • Relevance • Implication • Coping potential • Normative significance CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Appraisal theory takeaway Emotions arise from appraisal of goals and beliefs – Emphasizes centrality of beliefs, desires and intentions to emotion elicitation Event has no meaning in of itself Emotion arises from how event impacts goals and beliefs Same event will have different meaning to different people CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Classic example CSCI 534(Affective Computing) – Lecture by Jonathan Gratch But not always so simple Belief: I’m standing in a room CSCI 534(Affective Computing) – Lecture by Jonathan Gratch But not always so simple Belief: I’m standing in a room Does this contradict appraisal theory? CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Example (Constructivist Theory) Argues first step in the experience of emotion is physiological arousal – Seeing the bear triggers low-level automatic reactions such as arousal and running away We next try to find a label to explain our feelings, usually by looking at what we are doing (behavior) and what else is happening at the time of arousal (environment) Thus, we don’t just feel angry, happy, etc. We experience general feeling and then decide what they mean (a specific emotion) CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Schachter 2-factor theory CSCI 534(Affective Computing) – Lecture by Jonathan Gratch CSCI 534(Affective Computing) – Lecture by Jonathan Gratch CSCI 534(Affective Computing) – Lecture by Jonathan Gratch CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Practical implication CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Basic emotion Theory Constructivist Theory Appraisal Theory CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Lesson: Definitions matter Geocentricity – Placing earth at center of universe makes it difficult to predict motion of the planets Alchemy – All substance can be decomposed into earth, water, air and fire making it difficult to predict consequences of chemical reactions Point: – Theory important: allows us make specific predictions and explain variance – Important steps on way to deeper understanding – Recognize that technological choices depend (implicitly or explicitly) on (folk or scientific) theoretical assumptions and failure of the technology may reflect problems with theory, not software CSCI 534(Affective Computing) – Lecture by Jonathan Gratch End of main lecture CSCI 534(Affective Computing) – Lecture by Jonathan Gratch In-class exercise Split class into 3 groups • Need group of four volunteers to watch a video • Most of class will stay put and watch this group • Need one more group of four to watch the class I’ll give out some handouts • First group will mark down how they feel watching the video • Class will guess what the first group is feeling based on their reactions • Last group will guess what the first group is feeling based on class’s reactions NO TALKING CSCI 534(Affective Computing) – Lecture by Jonathan Gratch CSCI 534(Affective Computing) – Lecture by Jonathan Gratch Discussion Classification – What featured did you use to identify the felt emotion Dimensions vs. Basic emotions – Which framework best captured the “meaning” of the interaction Observers – Why were (or weren’t) the 3rd group able to infer what is going on Mirroring How do you think a computer would do? CSCI 534(Affective Computing) – Lecture by Jonathan Gratch 65 CSCI 534(Affective Computing) – Lecture by Jonathan Gratch