Evolution of emotion

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The study of the evolution of emotions dates back to the 19th century. Evolution and natural selection has been applied to the study of human communication, mainly by Charles Darwin in his 1872 work, The Expression of the Emotions in Man and Animals . [1] Darwin researched the expression of emotions in an effort to support his materialist theory of unguided evolution. He proposed that much like other traits found in animals, emotions apparently also evolved and were adapted over time. [2] His work looked at not only facial expressions in animals and specifically humans, but attempted to point out parallels between behaviors in humans and other animals.

Contents

According to evolutionary theory, different emotions evolved at different times. Primal emotions, such as love and fear, are associated with ancient parts of the psyche. Social emotions, such as guilt and pride, evolved among social primates. Evolutionary psychologists consider human emotions to be best adapted to the life our ancestors led in nomadic foraging bands.

Origins

Darwin's original plan was to include his findings about expression of emotions in a chapter of his work, The Descent of Man, and Selection in Relation to Sex (Darwin, 1871) but found that he had enough material for a whole book. It was based on observations, both those around him and of people in many parts of the world. One important observation he made was that even in individuals who were born blind, body and facial expressions displayed are similar to those of anyone else. The ideas found in his book on universality of emotions were intended to go against Sir Charles Bell's 1844 claim [3] that human facial muscles were created to give them the unique ability to express emotions. [2] The main purpose of Darwin's work was to support the theory of evolution by demonstrating that emotions in humans and other animals are similar. Most of the similarities he found were between species closely related, but he found some similarities between distantly related species as well. He proposed the idea that emotional states are adaptive, and therefore only those able to express certain emotions passed on their characteristics. [1]

Darwin's principles

In the 1872 work, Darwin proposed three principles. The first of the three is the "principle of serviceable habits", which he defined as we have certain habits or we perform different actions in certain states of mind, which get associated when that state of mind is induced, even when its not needed then. He used as an example contracting of eyebrows (furrowing the brow), which he noted is serviceable to prevent too much light from entering the eyes. He also said that the raising of eyebrows serves to increase the field of vision. He cited examples of people attempting to remember something and raising their brows, as though they could "see" what they were trying to remember.

The second of the principles is that of antithesis. While some habits are serviceable, Darwin proposed that some actions or habits are carried out merely because they are opposite in nature to a serviceable habit, but are not serviceable themselves. Shrugging of the shoulders is an example Darwin used of antithesis, because it has no service. Shoulder shrugging is a passive expression, and very opposite of a confident or aggressive expression. [1]

The third of the principles is expressive habits, or nervous discharge from the nervous system. This principle proposes that some habits are performed because of a build-up to the nervous system, which causes a discharge of the excitement. Examples include foot and finger tapping, as well as vocal expressions and expressions of anger. Darwin noted that many animals rarely make noises, even when in pain, but under extreme circumstances they vocalize in response to pain and fear. [1]

Research

Paul Ekman is most noted in this field for conducting research involving facial expressions of emotions. His work provided data to back up Darwin's ideas about universality of facial expressions, even across cultures. He conducted research by showing photographs exhibiting expressions of basic emotion to people and asking them to identify what emotion was being expressed. In 1971, Ekman and Wallace Friesen presented to people in a preliterate culture a story involving a certain emotion, along with photographs of specific facial expressions. The photographs had been previously used in studies using subjects from Western cultures. When asked to choose, from two or three photographs, the emotion being expressed in the story, the preliterate subjects' choices matched those of the Western subjects most of the time. These results indicated that certain expressions are universally associated with particular emotions, even in instances in which the people had little or no exposure to Western culture. The only emotions the preliterate people found hard to distinguish between were fear and surprise. [4] Ekman noted that while universal expressions do not necessarily prove Darwin's theory that they evolved, they do provide strong evidence of the possibility. [5] He mentioned the similarities between human expressions and those of other primates, as well as an overall universality of certain expressions to back up Darwin's ideas. The expressions of emotion that Ekman noted as most universal based on research are: anger, fear, disgust, sadness, and enjoyment. [5]

A common view is that facial expressions initially served a non-communicative adaptive function. Thus, the widened eyes in the facial expression of fear have been shown to increase the visual field and the speed of moving the eyes which helps finding and following threats. The wrinkled nose and mouth of the facial expression of disgust limit the intake of foul-smelling and possibly dangerous air and particles. Later, such reactions, which could be observed by other members of the group, increasingly become more distinctive and exaggerated in order to fulfill a primarily socially communicative function. This communicative function can dramatically or subtly influence the behavior of other members in the group. Thus, rhesus monkeys or human infants can learn to fear potential dangers based on only the facial expressions of fear of other group members or parents. Seeing fear expressions increases the tendency for flight responses while seeing anger expressions increases the tendency for fight responses. Classical conditioning studies have found that it is easier to create a pairing between a negative stimulant and anger/fear expressions than between a negative stimulant and a happiness expression. Cross-cultural studies and studies on the congenitally blind have found that these groups display the same expressions of shame and pride in situations related to social status. These expressions have clear similarities to displays of submission and dominance by other primates. Humans viewing expression of pride automatically assign a higher social status to such individuals than to those expressing other emotions. [6]

Expressed emotions and adaptive functions [6]
Expressed emotionInitial physiological functionEvolved communicative function
Fear Increased visual field and speed of eye movement from widened eyesWarning of potential threats. Appeasement to aggressor.
Surprise Increased visual field from widened eyesMore research needed
Disgust Constriction of face openings reduce dangerous inhalationsWarning of dangerous foods, behaviors, and ideas
Happiness More research neededAbsence of threat
Sadness More research neededVision handicapped by tears to show appeasement. Gain sympathy.
Anger More research neededWarning of impending threats. Signals dominance.
Pride Increased lung volume in preparation for encountering challengersIncreased social status.
Shame/Embarrassment Reduces and hides vulnerable body areas from potential attacksDecreased social status. Wish for appeasement.

Robert Zajonc published two reviews in 1989 of the "facial efference theory of emotion", also known as facial feedback theory, [7] [8] which he had first introduced to the scientific literature in an article published in Science in 1985. [9] This theory proposes that the facial musculature of mammals can control the temperature of the base of the brain (in particular the hypothalamus) by varying the degree of forward and backward flow through a vascular network (a so-called rete mirabile ). The theory is based on the idea that increasing the temperature of portions of the hypothalamus can produce aggressive behavior, whereas cooling can produce relaxation. Our emotional language has comparable descriptors, such as "hot-head" and "cool-breezy". The theory offers an explanation for the evolution of common facial expressions of emotion in mammals. Little experimental work has been done to extend the theory, however.

Carroll Izard discussed gains and losses associated with the evolution of emotions. He said that discrete emotion experiences emerge in ontogeny before language or conceptual structures that frame the qualia known as discrete emotion feelings are acquired. He noted that in evolution, when humans gained the capability of expressing themselves with language, this contributed greatly to emotional evolution. Not only can humans articulate and share their emotions, they can use their experiences to foresee and take appropriate action in future experiences. He did, however, raise the question of whether or not humans have lost some of their empathy for one another, citing things such as murder and crime against one another as destructive. [10]

Joseph LeDoux focuses much of his research on the emotion fear. Fear can be evoked by two systems in the brain, both involving the thalamus and the amygdala: one old, short and fast, the other more recently evolved, more circuitous and slower. In the older system, sensory information travels directly and quickly from the thalamus to the amygdala where it elicits the autonomic and motor responses we call fear. In the younger system, sensory information travels from the thalamus to the relevant cortical sensory areas (touch to the somatosensory cortex, vision to the visual cortex, etc.) and on to frontal association areas, where appraisal occurs. These frontal areas communicate directly with the amygdala and, in light of appraisal, may reduce or magnify the amygdala's fear response. If you glimpse what looks like a snake, long before your younger frontal areas have had time to determine it is a stick, the old thalamus-amygdala system will have evoked fear. LeDoux hypothesizes that the old fast system persists because a behavioral response at the first hint of danger is of little consequence when mistaken but may mean the difference between life and death when appropriate. [11] [12]

See also

Related Research Articles

<span class="mw-page-title-main">Emotion</span> Conscious subjective experience of humans

Emotions are mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is no scientific consensus on a definition. Emotions are often intertwined with mood, temperament, personality, disposition, or creativity.

A facial expression is one or more motions or positions of the muscles beneath the skin of the face. According to one set of controversial theories, these movements convey the emotional state of an individual to observers. Facial expressions are a form of nonverbal communication. They are a primary means of conveying social information between humans, but they also occur in most other mammals and some other animal species.

<span class="mw-page-title-main">Paul Ekman</span> American psychologist (born 1934)

Paul Ekman is an American psychologist and professor emeritus at the University of California, San Francisco who is a pioneer in the study of emotions and their relation to facial expressions. He was ranked 59th out of the 100 most cited psychologists of the twentieth century. Ekman conducted seminal research on the specific biological correlations of specific emotions, attempting to demonstrate the universality and discreteness of emotions in a Darwinian approach.

A microexpression is a facial expression that only lasts for a short moment. It is the innate result of a voluntary and an involuntary emotional response occurring simultaneously and conflicting with one another, and occurs when the amygdala responds appropriately to the stimuli that the individual experiences and the individual wishes to conceal this specific emotion. This results in the individual very briefly displaying their true emotions followed by a false emotional reaction.

Amusement is the state of experiencing humorous and entertaining events or situations while the person or animal actively maintains the experience, and is associated with enjoyment, happiness, laughter and pleasure. It is an emotion with positive valence and high physiological arousal.

<span class="mw-page-title-main">Facial Action Coding System</span> System of classifying human facial movements

The Facial Action Coding System (FACS) is a system to taxonomize human facial movements by their appearance on the face, based on a system originally developed by a Swedish anatomist named Carl-Herman Hjortsjö. It was later adopted by Paul Ekman and Wallace V. Friesen, and published in 1978. Ekman, Friesen, and Joseph C. Hager published a significant update to FACS in 2002. Movements of individual facial muscles are encoded by the FACS from slight different instant changes in facial appearance. It has proven useful to psychologists and to animators.

Robert Bolesław Zajonc was a Polish-born American social psychologist who is known for his decades of work on a wide range of social and cognitive processes. One of his most important contributions to social psychology is the mere-exposure effect. Zajonc also conducted research in the areas of social facilitation, and theories of emotion, such as the affective neuroscience hypothesis. He also made contributions to comparative psychology. He argued that studying the social behavior of humans alongside the behavior of other species, is essential to our understanding of the general laws of social behavior. An example of his viewpoint is his work with cockroaches that demonstrated social facilitation, evidence that this phenomenon is displayed regardless of species. A Review of General Psychology survey, published in 2002, ranked Zajonc as the 35th most cited psychologist of the 20th century. He died of pancreatic cancer on December 3, 2008 in Palo Alto, California.

<i>The Expression of the Emotions in Man and Animals</i> Book by Charles Darwin (1872)

The Expression of the Emotions in Man and Animals is Charles Darwin's third major work of evolutionary theory, following On the Origin of Species (1859) and The Descent of Man (1871). Initially intended as a chapter in The Descent of Man, The Expression grew in length and was published separately in 1872. This book concerns the biological aspects of emotional life, and Darwin explores the animal origins of such human characteristics as the lifting of the eyebrows in moments of surprise and the raising of the upper lip in an aggressive sneer. A German translation of The Expression appeared in 1872; Dutch and French versions followed in 1873 and 1874. A second edition of the book, with only minor alterations, was published in 1890. Since its first publication, The Expression has never been out of print, but it has also been described as Darwin's "forgotten masterpiece".

An emotional expression is a behavior that communicates an emotional state or attitude. It can be verbal or nonverbal, and can occur with or without self-awareness. Emotional expressions include facial movements like smiling or scowling, simple behaviors like crying, laughing, or saying "thank you," and more complex behaviors like writing a letter or giving a gift. Individuals have some conscious control of their emotional expressions; however, they need not have conscious awareness of their emotional or affective state in order to express emotion.

<span class="mw-page-title-main">Affective neuroscience</span> Study of the neural mechanisms of emotion

Affective neuroscience is the study of how the brain processes emotions. This field combines neuroscience with the psychological study of personality, emotion, and mood. The basis of emotions and what emotions are remains an issue of debate within the field of affective neuroscience.

<span class="mw-page-title-main">Emotionality</span>

Emotionality is the observable behavioral and physiological component of emotion. It is a measure of a person's emotional reactivity to a stimulus. Most of these responses can be observed by other people, while some emotional responses can only be observed by the person experiencing them. Observable responses to emotion do not have a single meaning. A smile can be used to express happiness or anxiety, while a frown can communicate sadness or anger. Emotionality is often used by experimental psychology researchers to operationalize emotion in research studies.

The facial feedback hypothesis, rooted in the conjectures of Charles Darwin and William James, is that one's facial expression directly affects their emotional experience. Specifically, physiological activation of the facial regions associated with certain emotions holds a direct effect on the elicitation of such emotional states, and the lack of or inhibition of facial activation will result in the suppression of corresponding emotional states.

According to some theories, emotions are universal phenomena, albeit affected by culture. Emotions are "internal phenomena that can, but do not always, make themselves observable through expression and behavior". While some emotions are universal and are experienced in similar ways as a reaction to similar events across all cultures, other emotions show considerable cultural differences in their antecedent events, the way they are experienced, the reactions they provoke and the way they are perceived by the surrounding society. According to other theories, termed social constructionist, emotions are more deeply culturally influenced. The components of emotions are universal, but the patterns are social constructions. Some also theorize that culture is affected by emotions of the people.

Discrete emotion theory is the claim that there is a small number of core emotions. For example, Silvan Tomkins concluded that there are nine basic affects which correspond with what we come to know as emotions: interest, enjoyment, surprise, distress, fear, anger, shame, dissmell and disgust. More recently, Carroll Izard at the University of Delaware factor analytically delineated 12 discrete emotions labeled: Interest, Joy, Surprise, Sadness, Anger, Disgust, Contempt, Self-Hostility, Fear, Shame, Shyness, and Guilt.

<span class="mw-page-title-main">Emotion classification</span> Contrast of one emotion from another

Emotion classification, the means by which one may distinguish or contrast one emotion from another, is a contested issue in emotion research and in affective science. Researchers have approached the classification of emotions from one of two fundamental viewpoints:

  1. that emotions are discrete and fundamentally different constructs
  2. that emotions can be characterized on a dimensional basis in groupings
<span class="mw-page-title-main">Disgust</span> Basic emotion

Disgust is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful or unpleasant. In The Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste, and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research has continually proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder.

<span class="mw-page-title-main">Amygdala hijack</span> Type of emotional response

An amygdala hijack is an emotional response that is immediate, overwhelming, and out of measure with the actual stimulus because it has triggered a much more significant emotional threat. The term, coined by Daniel Goleman in his 1996 book Emotional Intelligence: Why It Can Matter More Than IQ, is used by affective neuroscientists and is considered a formal academic term. The amygdala is made up of two small, round structures located closer to the forehead than the hippocampi, near the temporal lobes. The amygdalae are involved in detecting and learning which parts of our surroundings are important and have emotional significance. They are critical for the production of emotion. They are known to be very important for negative emotions, especially fear. Amygdala activation often happens when we see a potential threat. The amygdala uses our past, related memories to help us make decisions about what is currently happening.

Emotion perception refers to the capacities and abilities of recognizing and identifying emotions in others, in addition to biological and physiological processes involved. Emotions are typically viewed as having three components: subjective experience, physical changes, and cognitive appraisal; emotion perception is the ability to make accurate decisions about another's subjective experience by interpreting their physical changes through sensory systems responsible for converting these observed changes into mental representations. The ability to perceive emotion is believed to be both innate and subject to environmental influence and is also a critical component in social interactions. How emotion is experienced and interpreted depends on how it is perceived. Likewise, how emotion is perceived is dependent on past experiences and interpretations. Emotion can be accurately perceived in humans. Emotions can be perceived visually, audibly, through smell and also through bodily sensations and this process is believed to be different from the perception of non-emotional material.

Facial expressions are used to communicate emotions. They can also occur solitarily, without other people being present. People often imagine themselves in social situations when alone, resulting in solitary facial expressions. Toddlers and children in early childhood use social cues and contexts to discriminate and recognize facial expressions. They develop at this early stage facial expressions in order to provoke reactions from their caregivers and receive nurturance and support. Children reflect their peers' emotions in their own expressions for social interaction.

Facial coding is the process of measuring human emotions through facial expressions. Emotions can be detected by computer algorithms for automatic emotion recognition that record facial expressions via webcam. This can be applied to better understanding of people’s reactions to visual stimuli.

References

  1. 1 2 3 4 Darwin, C. (2007) [1872]. The expression of the emotions in man and animals . New York: Filiquarian. ISBN   978-0-8014-1990-4.
  2. 1 2 Hess, U.; Thibault, P. (2009). "Darwin and Emotion Expression". American Psychologist. 64 (2): 120–8. doi:10.1037/a0013386. PMID   19203144.
  3. ↑ Bell, C. (1844). The anatomy and philosophy of expression as connected with the fine arts (3 ed.). London: John Murray.
  4. ↑ Ekman, P; Friesen, W (1971). "Constants across cultures in the face and emotion" (PDF). Journal of Personality and Social Psychology. 17 (2): 124–9. doi:10.1037/h0030377. PMID   5542557. Archived from the original (PDF) on 2015-02-28. Retrieved 2015-02-28.
  5. 1 2 Ekman, P. (1993). "Facial expression and emotion" (PDF). American Psychologist. 48 (4): 384–92. doi:10.1037/0003-066X.48.4.384. PMID   8512154. Archived from the original (PDF) on 2012-06-11. Retrieved 2013-10-10.
  6. 1 2 Shariff, A. F.; Tracy, J. L. (2011). "What Are Emotion Expressions For?". Current Directions in Psychological Science. 20 (6): 395. doi:10.1177/0963721411424739. S2CID   18876999.
  7. ↑ Adelmann, P. K.; Zajonc, R. B. (1989). "Facial efference and the experience of emotion". Annual Review of Psychology . 40: 249–280. doi:10.1146/annurev.ps.40.020189.001341. PMID   2648977.
  8. ↑ Zajonc, R. B.; Murphy, S. T.; Inglehart, M. (1989). "Feeling and facial efference: Implications for the vascular theory of emotion". Psychological Review. 96 (3): 395–416. doi:10.1037/0033-295X.96.3.395. PMID   2756066.
  9. ↑ Zajonc1, R.B. (1985). "Emotion and facial efference: a theory reclaimed". Science. 228 (4695): 15–21. Bibcode:1985Sci...228...15Z. doi:10.1126/science.3883492. PMID   3883492.
  10. ↑ Izard, C. (2009). "Emotion Theory and Research: Highlights, Unanswered Questions, and Emerging Issues". Annual Review of Psychology . 60 (1): 1–25. doi:10.1146/annurev.psych.60.110707.163539. PMC   2723854 . PMID   18729725.
  11. ↑ LeDoux, J (1998). "The emotional brain". In Jenkins, JM; Oatley, K; Stein, NL (eds.). Human Emotions: A reader. Malden, Massachusetts: Blackwell Publishers. pp. 98–111. ISBN   0-631-20747-3.
  12. ↑ Ledoux, J. (1996). "Emotion Theory and Research: Highlights, Unanswered Questions, and Emerging Issues". Annual Review of Psychology . 60 (1): 1–25. doi:10.1146/annurev.psych.60.110707.163539. PMC   2723854 . PMID   18729725.
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