# Motivation and emotion/Book/2013/Facial expressions and the emotions of others

Facial expressions and the emotions of others
* Multimedia presentation (5 min)
Overview
Ever wondered why you appear to be happier around happy people and annoyed around annoyed people? A concept that explains this is called Emotional Contagion. So what is Emotional Contagion? According to Schoenwolf (1990) Emotional Contagion is a process which a person or group influences the emotions of another person or group through the conscious or unconscious induction of emotional states. It is said that although people don’t generally act identical to those around them, emotions and moods of surrounding people can rub off on us.
There are many theories that help explain emotional contagion. However, three concepts that provide leading evidence for emotional contagion are Facial Feedback Hypothesis, the Mirror Neuron System and the Facial Mimicry Hypothesis. Facial Feedback Hypothesis refers to the idea that ones facial expressions can affect emotional experience (Buck, 1980). While, the Mirror Neuron System refers to a group of neurons that mimics the facial expressions, attitudes and talking tones of those around us (Rizzolatti, 2004). Finally, the Facial Mimicry Hypothesis states that observers tend to show emotional facial expressions that are consistent with the expressions shown by the sender (Sato et al, 2013).
Quiz
1
Emotional Contagion Explains why:
people reflect moods that are starkly different from those surrounding them.
people are happier around sad people and sadder around happy people.
people get angry at others' success stories.
people tend to be happier around happy people and sadder around sad people.
2
The Mirror Neuron System may explain why we:
Always tends to be copycats
Mimic Facial Expressions
Act Happy
Are stone-faced
3
An example of Facial Feedback is:
Smiling followed by happy feelings
Frowning followed by happy feelings
Verbal Indication of happiness
Anger followed by sad feelings
Emotion Theorists
When it comes to theories of emotion, there is no shortage. The study of the evolution of emotions dates back to the 19th century. Many psychologists and theorists have offered many ideas and theories concerning how and why people experience emotion. There have been three main influential psychologists that have helped shape the evolution of emotion. These include Charles Darwin, Paul Ekman and William James. These theories of emotion helps us to understand emotional expression and how it influences emotions in others.
Charles Darwin
In the 1870s, Charles Darwin proposed that emotions evolved because they had adaptive value. In his book The Expression of the Emotions in Man and Animals (1872) Darwin theorized that human emotional expressions have evolved over time because of their link with reactions that have had adaptive or survival value (Darwin, 1872). For example, an animal baring its teeth in rage is literally preparing to fight; thus its emotion gives it a physical advantage (Clark, 1984).. Similarly, Darwin hypothesized that the "fight or flight" reaction, a heightened state of nervous arousal, was a mechanism that aided survival. For example, fear evolved because it helped people to act in ways that enhanced their chances of survival (Clark, 1984). He suggested that human reactions which no longer have any clear survival value probably did in the past and that the similarity of emotional expression among all known human groups suggests a common descent from an earlier pre-human ancestor (Clark, 1984). Most of his research supports the theory that emotions in humans and other animals are similar, therefore making emotional expression universal. Majority of the similarities in facial expression he found were in species closely related but he also found similarities in distantly related species as well (Darwin, 1872). Finally, Darwin believed that facial expressions of emotion are innate (hard-wired). He pointed out that facial expressions allow people to quickly judge someone’s hostility or friendliness and to communicate intentions to others (Clark, 1984).
Paul Ekman (Facial Action Coding System)
Paul Ekman is undoubtedly the most influential researcher in emotional expression. Paul Ekman studied the relationship between emotions, facial expressions and overall body language. Ekman stated that emotions were universal and felt by people of all different cultures (Ekman, 1992). Ekman conducted research in ten different cultures, including isolated tribes in Papua New Guinea, where tribesmen who had never been exposed to the modern world were able to interpret facial expressions exactly as Westerners would (Ekman & Friesen, 1971). Although there are some differences in expression of emotions across cultures, Ekman believed that there were basic emotions that could be classified. This list of universal facial expressions, which Ekman first developed in 1972, comprises the six basic emotions (Ekman, 1992b). These include; Anger, Happiness, Surprise, Disgust, Sadness and Fear (Ekman, 1992b)
Ekman, along with Wallace Friesen, devised the Facial Action Coding System (FACS) to categorize and measure every type of facial expression. Facial behaviors include individual facial movements such as pulling the eyebrows up, as well as more general facial activities like turns and tilts of the head (Ekman & Friesen, 1978). They developed the FACS by determining how the contraction of each facial muscle changes the appearance of the face (Ekman & Friesen, 1978). FACS are measured in Action Units (AU’s), not muscles and consist of 46 action units, which produce around 7,000 different combinations. This provides the essential detail needed in determining different facial expressions (Sayette, Cohn, Wertz, Perrott, Parrot, 2001). For example, according to FACS, the expression for Fear includes a combination of the eyes widening (AU 5), upper lids raise as in surprise but the brows draw together (AU 1, 2, 4), the lips stretch horizontally (AU 20) (Sayette, Cohn, Wertz, Perrott, Parrot, 2001). Today the development of FACS has progressed and updated to computer software and has been made vital in lie detection.
William James (James-Lange Theory)
In the 1880s, two theorists, psychologist William James and physiologist Carl Lange, proposed an idea that challenged beliefs about emotion. This theory is known as the James-Lange theory. According to this theory, people experience emotion because they perceive their bodies’ physiological responses to external events (Cannon, 1927). James and Lange both believed that, when an event occurs, our body reacts, and then we feel emotion after the brain interprets that physiological change (Cannon, 1927). This theory states that people don’t cry because they feel sad. Rather, people feel sad because they cry, and, likewise, they feel happy because they smile (Lang, 1994). Therefore, this theory suggests that different physiological states correspond to different experiences of emotion (Lang, 1994).
James-Lange Theory of Emotion
Six Universal Facial Expressions
Anger
Anger is probably the most dangerous emotion (Ekman and Friesen, 2003). Anger varies in intensity, from slight irritation or annoyance to rage or fury. Anger arises from other emotions such as irritation and annoyance and begins from the interpretation that one’s plans or well been have interfered with (Reeve, 2009). It can also arise from a betrayal of trust, receiving unwanted criticism and a lack of consideration (Reeve, 2009). Anger often results in violence and aggression due to the increase in people’s sense of control (Reeve, 2009). When experiencing anger, individuals show the following facial expressions: raised or flared nostrils, a furrowed brow, wide open eyes, compressed mouth, and head in an erect position (Ekman and Friesen, 2003).
DefinitionFacial Muscular Movements
Antagonism toward a person or object often felt after you feel you’ve been wronged or offended.Raised or Flared nostrils; A Furrowed Brow; Wide Open Eyes, Compressed Mouth; Head in an Erect Position
Disgust
Disgust is the feeling of aversion (Ekman and Friesen, 2003). According to Reeve (2009) people tend to be disgusted in things that are contaminated, deteriorated or a spoiled object. The function of disgust is rejection. When an individual is disgusted, they seek to reject the aspects of where the disgusting object is placed in an environment (Reeve, 2009). Like anger, it varies in intensity, from nausea or vomiting to turning away from the object of disgust. When individuals experience disgust, they usually show facial expressions such as nose wrinkling, lower lip turned down, upper lip raised, mouth open, and protruding lips (Ekman and Friesen, 2003).
DefinitionFacial Muscular Movements
Intense displeasure or condemnation caused by something offensive or repulsiveNose Wrinkling; Lower lip turned down; Upper lip raised; Mouth open; Protruding lips
Fear
According to Reeve (2009) fear is an emotion in response to a situation that a person may find dangerous or threatening to one’s well being, which can be psychological or physical. Physical fear may vary from something minor such as a vaccination puncture to actual life-endangering injuries. Psychological fear can occur from minor insults or disappointments to extreme assaults on one’s being, rejection of ones love, attacks on ones worth, thus psychologically damaging self esteem, confidence, sense of security etc. (Ekman and Friesen, 2003). Fear also serves as a defense mechanism as it functions as a warning system for impending physical or psychological harm which then displays itself in the autonomic nervous system arousal to send signals out to the individual. These signals include trembling, perspiration, increased heart rate and blood pressure (Reeve, 2009). Facial expressions may include eyes widening, lips retracting, eyebrows raised and mouth opened. (Ekman and Friesen, 2003).
DefinitionFacial Muscular Movement
Feeling of apprehension caused by perception of danger, threat or infliction of pain.Eyes Widening; Lips Retracting; Eyebrows Raised; Mouth Opened
Happiness
Happiness is the emotion most people want to experience. It is characterized by feelings of pleasure, excitement and enjoyment (Ekman and Friesen, 2003). Majority of people choose situations in which they can experience happiness. These situations may include: upcoming events the individual is excited about, reaching a goal or receiving positive feedback (Ekman and Friesen, 2003). Ekman and Friesen (2003) describe the facial expressions in happiness as: crows feet wrinkles; pushed up cheeks; raised eyebrows; open wide eyes; gaping mouth.
DefinitionFacial Muscular Movement
Pleasant feeling of contentment and well-beingCrows feet wrinkles; Pushed up cheeks; Raised eyebrows; Open wide eyes; Gaping mouth
Sadness
Sadness is the most negative, aversive emotion usually following experiences of separation or failure (Reeve, 2009). Sadness is rarely a brief feeling. It usually last for a few hours, even days (Ekman and Friesen, 2003). Darwin defined sadness in an individual as “they no longer wish for action, but remain motionless and passive. The circulation becomes languid, the face pale; the muscles flaccid; the eyelids droop; the head hangs on the contracted chest; the lips, cheeks and lower jaw all sink downward from their own weight” (Darwin, 1965). Sadness, however, can motivate individuals to initiate any necessary behavior to alleviate the sad or distressing stimuli (Reeve, 2009).
DefinitionFacial Muscular Movement
Feeling of unhappiness or sorrowDrooping upper eyelids; Losing focus in eyes; Slight pulling down of lip corners.
Surprise
Surprise is the briefest emotion (Ekman and Friesen, 2003). Surprise is a brief feeling that quickly resolves into one of the other primary emotions, like happiness, anger or fear. (Ekman and Friesen, 2003). According to Ekman and Friesen (2003) it is often triggered by an unplanned, unexpected event which can be either a pleasant or unpleasant emotion depending on the situation. Facial expressions for surprise include; eyebrows raised, eyes widening and mouth open (Ekman and Friesen, 2003).
DefinitionFacial Muscular Movement
Feeling of upset or surprise at an unexpected occurrenceEyebrows raised; Eyes widened; Mouth open
Facial Mimicry Hypothesis
Facial Mimicry Hypothesis states that observers tend to show emotional facial expressions that are consistent with the expressions shown by the sender (Sato et al, 2013). Facial Mimicry has been of great interest to psychologists and researchers, in determining the psychological processes involved in facial mimicry and whether they influence emotions in others or not. Previous research have indicated and supported the hypothesis for Facial Mimicry influencing emotions in others. Dimberg (1982) showed that presenting photographs of angry and happy facial expressions to subjects influenced brow lowering actions typically found in angry facial expressions and lip-corner pulling actions typically found in happy facial expressions.
Blairy et al. (1999) proposed that the observation of others emotional facial expressions automatically induced facial mimicry. They state that facial mimicry leads to an emotional experience that produces emotions experienced by other people. Several other studies have supported this theory. Bush et al. (1989) demonstrated that controlling facial muscle activity altered emotional reactions while participants watched comedy films. Niedenthal et al. (2001) also demonstrated that controlling facial muscle activity influenced facial expressions. Richards et al. (2002) found that change in emotions were influenced by the recognition of other emotions portrayed in a stimulus. This research suggests there is a strong link between facial mimicry and the emotional experience it produces. Therefore, making it evident that facial mimicry can influence the emotions of others through the recognition of emotion.
Facial Feedback Hypothesis
The free expression by outward signs of an emotion intensifies it. On the other hand, the repression, as far as this is possible, of all outward signs softens our emotions... Even the simulation of an emotion tends to arouse it in our minds. -Charles Darwin
Facial Feedback Hypothesis refers to the idea that ones facial expressions can affect emotional experience (Buck, 1980). The Facial Feedback Hypothesis dates back to Charles Darwin who stated that the expression of an emotion intensifies it, whereas its repression softens it (Darwin, 1872). William James also contributed to the Facial Feedback Hypothesis through his theories of emotion. He states that the bodily changes that are felt after an event occurs and that the feeling of these bodily changes is the emotion (McIntosh, 1996).
Although Darwin and James differ in their view of the Facial Feedback Hypothesis, they both agree that the behavior that accompanies an emotion has a contributing influence on emotional experience (McIntosh, 1996).
Further research the Facial Feedback Hypothesis has indicated that facial expressions are important in determining how we feel. This also supports the James-Lange Theory in that experiencing an emotion is in response to a particular characteristic of that emotion. Ekman, Levenson and Friesen (1983) researched this hypothesis. Ekman et al. (1983) conducted a study to investigate facial feedback by asking people to play out particular facial expressions. In his study, participants were not told what the study was about but participants were given instructions like this:
'Raise your brows, while holding them raised pull your brows together. Now raise your upper eyelids and tighten your lower eyelids. Now stretch your lips horizontally'. (Ekman, 1983)
This set of instructions distinctly corresponds to the emotion of Fear. Ekman et al (1983) recorded a variety of physiological variables while participants were pulling these facial expressions. These included; skin temperature, heart rate, skin resistance; which measured how much people were sweating. Results indicated differences in emotions in determining the pattern of physiological responses. Ekman et al (1983) has demonstrated that expressing a certain emotion that participants were experiencing led them to produce other responses that were characteristic of that emotion. For example, the Fear expression led people to feel a little bit of fear, which also produced other responses that we associate with fear.
Lundqvist and Dinberg (1995)
also tested the Facial Feedback Hypothesis. They asked individuals to look at 'others' expressions, by asking them rate photographs of people who were smiling or frowning or looking afraid. Whilst doing this, they measured the electrical activity of the muscles in the face of their participants so that they were able to record changes in their expressions. Results indicated that observing others faces expressing particular emotions made changes to muscle activity, as well as in participant’s emotions. Both Lundqvist and Dinberg (1995) and Ekman et al (1983) results illustrate that emotion can be a social phenomenon, indicating that different situations may cause emotional contagion.
Mirror Neuron System
The Mirror Neuron System refers to a group of neurons that mimics the facial expressions, attitudes and talking tones of those around us (Rizzolatti, 2004). There is still some debate about the function of mirror neurons. However, many researchers studying cognition have argued that mirror neurons may be important for understanding the actions of other people and for learning new skills by imitation (Ramachandran, 2000). Whilst, other researchers state that mirror neurons are responsible for observed actions, contributing to theory of mind skills, as well as language abilities (Oberman & Ramachandran, 2009). Research done by Lamm et al (2007) states that mirror neurons help us to understand the actions and intentions of other people. He argued that mirror neurons determine the human capacity for emotions such as empathy.
Wicker et al (2003) have argued that the mirror neuron system is involved in influencing emotions of others. They conducted a number of studies using fMRI that showed that certain brain regions activate when people experience an emotion such as disgust, happiness, pain etc and when they see another person experiencing an emotion. Wicker et al (2003) conducted a study where participants were asked to inhale odorants that were selected to produce feelings of disgust, as well as viewing video clips of other individuals exhibiting the facial expression of disgust. They found that the mirror neuron system activates the observer’s motor representation of that action, therefore, in this case, observing an emotion activates the neural representation of that emotion (Wicker et al, 2003). This research provides evidence for understanding the behavior of others through facial expressions.
Application to theory
The ability to understand and express emotions starts developing from birth. From around two months, most babies will laugh and show signs of fear. By 12 months, a typically developing baby can read your face to get an understanding of what you’re feeling. Most toddlers and young children start to use words to express feelings. Throughout childhood and adolescence, most children continue building empathy, self-regulation, and skills in recognising and responding to other people’s feelings. By adulthood, people are usually able to quickly recognise subtle emotional expressions.
Children with autism spectrum disorder (ASD) often find it hard to recognise and control emotions. However, research in this area is improving and their skills in reading facial expressions can be improved, which in turn can help them understand and respond more appropriately to other people.
Ongoing research done by Gay, Leijdekkers and Wong (2013) have described an app that can be used on smartphones and tablets. This app is called CaptureMyEmotion. It works by using wireless sensors to capture physiological data together with facial expression recognition to provide a way to help autistic children identify and understand their emotions. CaptureMyEmotion enables autistic children to capture photos, videos or sounds, and identify the emotion they felt while taking the picture. Simultaneously, a self-portrait of the child is taken, and the app measures the arousal and stress levels using wireless sensors (Gay, Leijdekkers and Wong, 2013). The app uses the self-portrait to provide a better estimate of the emotion felt by the child. The app has the potential to help autistic children understand their emotions and it gives the parent/carer insight into the child's emotions and offers a means to discuss the child's feelings (Gay, Leijdekkers and Wong, 2013). Advanced technology such as the CaptureMyEmotion app is developing and making it alot easier for Autistic children and their parents, as well as other people in learning how to communicate through emotions.
To Consider
Although there is no research found. Future research could look at whether facial expressions can cause an opposite effect in people. For example, instead of facial expressions of happiness influencing other people to experience happiness. It could be said that in some social groups, been around loud and outgoing people can cause some people to become shy and reserved who do not normally act shy and reserved.
Conclusion
Facial Expressions have longed in helping us understand the behavior and emotions of other individuals. This book chapter expresses through the theories of Emotional Contagion that facial expressions can affect emotions in others. A number of theorists such as Charles Darwin, Paul Ekman and William James have provided considerable evidence on facial expressions and this has helped us determine why we experience emotion and how it can influence others emotions. By looking at a number of theories such as the Facial Feedback Hypothesis, Facial Mimicry Hypothesis and the Mirror Neuron system, we are more effectively able to see different approaches of how facial expressions can affect emotions of others, whether it be through imitation or through recognition of emotions in others.
See Also
Emotional Contagion (2013 Book Chapter)
Facial Expressions and Culture (2013 Book Chapter)
References
Blairy, S. Herrera, P. Hess, U. (1999) Mimicry and the judgment of emotional facial expressions. J. Nonverb. Behav. 23, 5–41.
Buck, R. (1980). Nonverbal behavior and the theory of emotion: The facial feedback hypothesis. Journal of Personality and Social Psychology, 38(5), 811-824.
Bush, L.K. Barr, C.L. McHugo, G.J. Lanzetta, J.T. (1989) The effects of facial control and facial mimicry on subjective reactions to comedy routines. Motiv Emo 13: 31–52. doi: 10.1007/BF00995543.
Cannon, W (1927) The James-Lange Theory of Emotions: A Critical Examination and an Alternative Theory. The American Journal of Psychology 39: 106–124.
Clark, Ronald W. (1984) The Survival of Charles Darwin: A Biography of a Man and an Idea. New York: Random House
Darwin, C. (1872). The expression of the emotions in man and animals. London:John Murray, 366.
Dimberg, U (1982) Facial reactions to facial expressions. Psychophysiology 19: 643–647. doi: 10.1111/j.1469-8986.1982.tb02516.x.
Ekman, P. (1992). Facial Expressions of Emotion: New Findings, New Questions. Psychological Science, 3, 1.
Ekman, P. (1992b). An argument for basic emotions. Cognition and Emotion, 6, 3-4.
Ekman, P., Levenson, R.W., Friesen, W.V. (1983). Autonomic nervous system activity distinguishes among emotions. Science, 221, 1208-1210.
Ekman, P., & Friesen, W. (1971). Constants across cultures in the face and emotion. Journal of Personality and Social Psychology, 17, 124-129.
Ekman, P., & Friesen, W. (1978). Facial Action Coding Systems (FACS): a Technique for the Measurement of Facial Action. California: Consulting Psychology Press.
Ekman, P., & Friesen, W. (2003) Unmasking The Face: A guide to recognizing emotions from facial expressions. Cambridge, MA: Malor Books
Gay V, Leijdekkers P, Wong F. (2013) Using sensors and facial expression recognition to personalize emotion learning for autistic children. Stud Health Technol Inform. 189:71-6.
Lamm, C. Batson, C.D. Decety, J. (2007). The neural substrate of human empathy: effects of perspective-taking and cognitive appraisal. Journal of Cognitive Neuroscience 19 (1): 42–58.
Lang, P.J. (1994) The Varieties of Emotional Experience: A Meditation on James–Lange Theory. Psychological Review 101 (2): 211–221.
Lundqvist, L.O., Dimberg, U. (1995). Facial expressions are contagious. Journal of Psychophysiology, 9, 203-211
McIntosh, D.N. (1996) Facial Feedback Hypotheses: Evidence, Implications and Directions. Motivation and Emotion, Vol. 20, No. 2
Niedenthal, P.M. Brauer, M. Halberstadt, J.B. Innes–Ker, A.H. (2001) When did her smile drop? Facial mimicry and the influences of emotional state on the detection of change in emotional expression. Cogn Emo 15: 853–864. doi: 10.1080/02699930143000194.
Oberman, L. Ramachandran, V.S. (2009). Reflections on the Mirror Neuron System: Their Evolutionary Functions Beyond Motor Representation. In Pineda, J.A. Mirror Neuron Systems: The Role of Mirroring Processes in Social Cognition. Humana Press. 39–62.
Ramachandram, V.S. (2000) Mirror neurons and imitation learning as the driving force behind “the great leap forward” in human evolution.
Reeve, J. (2009). Understanding motivation and emotion (5th ed.). Danvers, MA: John Wiley & Sons
Richards, A. French, C.C. Calder, A.J. Webb, B. Fox, R.(2002) Anxiety-related bias in the classification of emotionally ambiguous facial expressions. Emotion 2: 273–287. doi: 10.1037/1528-3542.2.3.273.
Rizzolatti, G. Craighero, L. (2004). The mirror neuron system. Annual Review of Neuroscience, 27, 169–92. doi: 10.1146/annurev.neuro.27.070203.144230
Sato W, Fujimura T, Kochiyama T, Suzuki N. (2013). Relationships among facial mimicry, emotional experience, and emotion recognition. PLoS ONE 8(3): e57889. doi:10.1371/journal.pone.0057889
Sayette, M., Cohn, J., Wertz, J., Perrott, M., Parrot, D. (2001). A psychometric evaluation of the Facial Action Coding System for assessing spontaneous expression. Journal of Nonverbal Behaviour, 25, 3.
Schoenewolf, G. (1990). Emotional contagion. Behavioural induction in individuals and groups. Modern Psychoanaylsis, 15: 49-61.
Wicker, B. Keysers, C. Plailly, J. Royet, J.P. Gallese, V. Rizzolatti, G. (2003). Both of Us Disgusted in My Insula: The Common Neural Basis of Seeing and Feeling Disgust, Neuron 40, 3, 655-64 :
* ↑ Schoenewolf, G (1990) Emotional Contagion. Behavioural induction in individuals and groups. Modern Psychoanaylsis, 15: 49-61
* ↑ Buck, R. (1980) Nonverbal Behavior and the Theory of Emotion: The Facial Feedback Hypothesis. Journal of Personality and Social Psychology, Vol. 38, No. 5, 811-824
* ↑ Rizzolatti, G. Craighero, L (2004) The Mirror Neuron System. Annu. Rev. Neurosci. 2004. 27:169–92 doi: 10.1146/annurev.neuro.27.070203.144230
* ↑ Sato W, Fujimura T, Kochiyama T, Suzuki N (2013) Relationships among Facial Mimicry, Emotional Experience, and Emotion Recognition. PLoS ONE 8(3): e57889. doi:10.1371/journal.pone.0057889
* ↑ Darwin, C. (1872). The expression of the emotions in man and animals. London:John Murray, 366.
* ↑ Clark, Ronald W. (1984) The Survival of Charles Darwin: A Biography of a Man and an Idea. New York: Random House
* ↑ Ekman, P. (1992). Facial Expressions of Emotion: New Findings, New Questions. Psychological Science, 3, 1.
* ↑ Ekman, P., & Friesen, W. (1971). Constants across cultures in the face and emotion. Journal of Personality and Social Psychology, 17, 124-129.
* ↑ Ekman, P. (1992b). An argument for basic emotions. Cognition and Emotion, 6, 3-4.
* ↑ Ekman, P., & Friesen, W. (1978). Facial Action Coding Systems (FACS): a Technique for the Measurement of Facial Action. California: Consulting Psychology Press.
* ↑ Sayette, M., Cohn, J., Wertz, J., Perrott, M., Parrot, D. (2001). A psychometric evaluation of the Facial Action Coding System for assessing spontaneous expression. Journal of Nonverbal Behaviour, 25, 3.
* ↑ Cannon, W (1927) The James-Lange Theory of Emotions: A Critical Examination and an Alternative Theory. The American Journal of Psychology 39: 106–124.
* ↑ Lang, P.J. (1994) The Varieties of Emotional Experience: A Meditation on James–Lange Theory. Psychological Review 101 (2): 211–221.
* ↑ Ekman, P., & Friesen, W. (2003) Unmasking The Face: A guide to recognizing emotions from facial expressions. Cambridge, MA: Malor Books
* ↑ Reeve, J. (2009). Understanding motivation and emotion (5th ed.). Danvers, MA: John Wiley & Sons
* ↑ Dimberg, U (1982) Facial reactions to facial expressions. Psychophysiology 19: 643–647. doi: 10.1111/j.1469-8986.1982.tb02516.x.
* ↑ Blairy, S. Herrera, P. Hess, U. (1999) Mimicry and the judgment of emotional facial expressions. J. Nonverb. Behav. 23, 5–41.
* ↑ Bush, L.K. Barr, C.L. McHugo, G.J. Lanzetta, J.T. (1989) The effects of facial control and facial mimicry on subjective reactions to comedy routines. Motiv Emo 13: 31–52. doi: 10.1007/BF00995543.
* ↑ Niedenthal, P.M. Brauer, M. Halberstadt, J.B. Innes–Ker, A.H. (2001) When did her smile drop? Facial mimicry and the influences of emotional state on the detection of change in emotional expression. Cogn Emo 15: 853–864. doi: 10.1080/02699930143000194.
* ↑ Richards, A. French, C.C. Calder, A.J. Webb, B. Fox, R.(2002) Anxiety-related bias in the classification of emotionally ambiguous facial expressions. Emotion 2: 273–287. doi: 10.1037/1528-3542.2.3.273.
* ↑ Darwin, C. (1872). The Expression of the emotions in man and animals. London:John Murray, 366.
* ↑ McIntosh, D.N. (1996) Facial Feedback Hypotheses: Evidence, Implications and Directions. Motivation and Emotion, Vol. 20, No. 2
* ↑ Ekman, P., Levenson, R.W., Friesen, W.V. (1983). Autonomic nervous system activity distinguishes among emotions. Science, 221, 1208-1210.
* ↑ Lundqvist, L.O., Dimberg, U. (1995). Facial expressions are contagious. Journal of Psychophysiology, 9, 203-211
* ↑ Ramachandram, V.S. (2000) Mirror neurons and imitation learning as the driving force behind “the great leap forward” in human evolution.
* ↑ Oberman, L. Ramachandran, V.S. (2009). Reflections on the Mirror Neuron System: Their Evolutionary Functions Beyond Motor Representation. In Pineda, J.A. Mirror Neuron Systems: The Role of Mirroring Processes in Social Cognition. Humana Press. 39–62.
* ↑ Lamm, C. Batson, C.D. Decety, J. (2007). The neural substrate of human empathy: effects of perspective-taking and cognitive appraisal. Journal of Cognitive Neuroscience 19 (1): 42–58.
* ↑ Wicker, B. Keysers, C. Plailly, J. Royet, J.P. Gallese, V. Rizzolatti, G. (2003). Both of Us Disgusted in My Insula: The Common Neural Basis of Seeing and Feeling Disgust, Neuron 40, 3, 655-64
* ↑ Gay V, Leijdekkers P, Wong F. (2013) Using sensors and facial expression recognition to personalize emotion learning for autistic children. Stud Health Technol Inform.189:71-6.