Facial expression

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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. (For a discussion of the controversies on these claims, see Fridlund [1] and Russell & Fernandez Dols. [2] )

Contents

Humans can adopt a facial expression voluntarily or involuntarily, and the neural mechanisms responsible for controlling the expression differ in each case. Voluntary facial expressions are often socially conditioned and follow a cortical route in the brain. Conversely, involuntary facial expressions are believed to be innate and follow a subcortical route in the brain.

Facial recognition can be an emotional experience for the brain and the amygdala is highly involved in the recognition process. The Amygdala is the integrative center for emotions, emotional behavior, and motivation.

The eyes are often viewed as important features of facial expressions. Aspects such as blinking rate can possibly be used to indicate whether a person is nervous or whether they are lying. Also, eye contact is considered an important aspect of interpersonal communication. However, there are cultural differences regarding the social propriety of maintaining eye contact or not.

Beyond the accessory nature of facial expressions in spoken communication between people, they play a significant role in communication with sign language. Many phrases in sign language include facial expressions in the display.

There is controversy surrounding the question of whether facial expressions are a worldwide and universal display among humans. Supporters of the Universality Hypothesis claim that many facial expressions are innate and have roots in evolutionary ancestors. Opponents of this view question the accuracy of the studies used to test this claim and instead believe that facial expressions are conditioned and that people view and understand facial expressions in large part from the social situations around them. Moreover, facial expressions have a strong connection with personal psychology. Some psychologists have the ability to discern hidden meaning from a person's facial expression. [ clarification needed ]

A 2020 study on "emotion residue" found that even when study participants attempted to make neutral facial expressions, their faces still retained emotion residue from prior expressions, and these prior expressions were able to be detected by observers. [3]

One experiment investigated the influence of gaze direction and facial expression on face memory. Participants were shown a set of unfamiliar faces with either happy or angry facial expressions, which were either gazing straight ahead or had their gaze averted to one side. Memory for faces that were initially shown with angry expressions was found to be poorer when these faces had averted as opposed to direct gaze, whereas memory for individuals shown with happy faces was unaffected by gaze direction. It is suggested that memory for another individual's face partly depends on an evaluation of the behavioural intention of that individual. [4]

Creation

Facial muscles

An actor acting out Drama Masks (Thalia and Melpomene) in 1972 Lars Jacob as Comedy & Tragedy 1972.JPG
An actor acting out Drama Masks (Thalia and Melpomene) in 1972

Facial expressions are vital to social communication between humans. They are caused by the movement of muscles that connect to the skin and fascia in the face. These muscles move the skin, creating lines and folds and causing the movement of facial features, such as the mouth and eyebrows. These muscles develop from the second pharyngeal arch in the embryo. The temporalis, masseter, and internal and external pterygoid muscles, which are mainly used for chewing, have a minor effect on expression as well. These muscles develop from the first pharyngeal arch. [5]

Neuronal pathways

There are two brain pathways associated with facial expression; the first is voluntary expression. Voluntary expression travels from the primary motor cortex through the pyramidal tract, specifically the corticobulbar projections. The cortex is associated with display rules in emotion, which are social precepts that influence and modify expressions. Cortically related expressions are made consciously. [5]

The second type of expression is emotional. These expressions originate from the extrapyramidal motor system, which involves subcortical nuclei. For this reason, genuine emotions are not associated with the cortex and are often displayed unconsciously. This is demonstrated in infants before the age of two; they display distress, disgust, interest, anger, contempt, surprise, and fear. Infants' displays of these emotions indicate that they are not cortically related. Similarly, blind children also display emotions, proving that they are subconscious rather than learned. Other subcortical facial expressions include the "knit brow" during concentration, raised eyebrows when listening attentively, and short "punctuation" expressions to add emphasis during speech. People can be unaware that they are producing these expressions. [5]

Asymmetries

The lower portions of the face are controlled by the opposite cerebral hemisphere, causing asymmetric facial expression. Because the right hemisphere is more specialised for emotional expression, emotions are more strongly expressed on the left side of the face., [6] particularly for negative emotions. [7] Asymmetries in expression can be seen in chimeric faces (facial portraits made by combining the left and right halves of faces with different expressions) [8] and also in portraits which more often show the left, more emotional side of the face than the right. [9]

Neural mechanisms in face perception

The amygdala plays an important role in facial recognition. Functional imaging studies have found that when shown pictures of faces, there is a large increase in the activity of the amygdala. The amygdala receives visual information from the thalamus via the subcortical pathways. [10] The amygdala may also have a significant role in the recognition of fear and negative emotions. It is believed that the emotion disgust is recognized through activation of the insula and basal ganglia. The recognition of emotion may also utilize the occipitotemporal neocortex, orbitofrontal cortex and right frontoparietal cortices. [11]

Gender and facial cues

More than anything though, what shapes a child's cognitive ability to detect facial expression is being exposed to it from the time of birth. The more an infant is exposed to different faces and expressions, the more able they are to recognize these emotions and then mimic them for themselves. Infants are exposed to an array of emotional expressions from birth, and evidence indicates that they imitate some facial expressions and gestures (e.g., tongue protrusion) as early as the first few days of life. [12] [ full citation needed ] In addition, gender affects the tendency to express, perceive, remember, and forget specific emotions. [13] [14] For instance, angry male faces and happy female faces are more recognizable, compared to happy male faces and angry female faces. [14]

Communication

Eye contact

A person's face, especially their eyes, creates the most obvious and immediate cues that lead to the formation of impressions. This article discusses eyes and facial expressions and the effect they have on interpersonal communication.

A person's eyes reveal much about how they are feeling, or what they are thinking. Blink rate can reveal how nervous or at ease a person may be. Research by Boston College professor Joe Tecce suggests that stress levels are revealed by blink rates. He supports his data with statistics on the relation between the blink rates of presidential candidates and their success in their races. Tecce claims that the faster blinker in the presidential debates has lost every election since 1980. [15] Though Tecce's data is interesting, it is important to recognize that non-verbal communication is multi-channeled, and focusing on only one aspect is reckless. Nervousness can also be measured by examining each candidates' perspiration, eye contact and stiffness. [16]

Within their first year, Infants learn rapidly that the looking behaviors of others convey significant information. Infants prefer to look at faces that engage them in mutual gaze and that, from an early age, healthy babies show enhanced neural processing of direct gaze. [17]

Eye contact is another major aspect of facial communication. Some have hypothesized that this is due to infancy, as humans are one of the few mammals who maintain regular eye contact with their mother while nursing. [18] Eye contact serves a variety of purposes. It regulates conversations, shows interest or involvement, and establishes a connection with others.

But different cultures have different rules for eye contact. Certain Asian cultures can perceive direct eye contact as a way to signal competitiveness, which in many situations may prove to be inappropriate. Others lower their eyes to signal respect, and similarly, eye contact is avoided in Nigeria; [19] however, in western cultures this could be misinterpreted as lacking self-confidence.

Even beyond the idea of eye contact, eyes communicate more data than a person even consciously expresses. Pupil dilation is a significant cue to a level of excitement, pleasure, or attraction. Dilated pupils indicate greater affection or attraction, while constricted pupils send a colder signal.

Sign languages

Facial expression is used in sign languages to convey specific meanings. In American Sign Language (ASL), for instance, raised eyebrows combined with a slightly forward head tilt to indicate that what is being signed is a yes–no question. Lowered eyebrows are used for wh-word questions. Facial expression is also used in sign languages to show adverbs and adjectives such as distance or size: an open mouth, squinted eyes and tilted back head indicate something far while the mouth pulled to one side and the cheek held toward the shoulder indicate something close, and puffed cheeks mean very large. It can also show the manner in which something is done, such as carelessly or routinely. [20] Some of these expressions, also called non-manual signs, are used similarly in different sign languages while others are different from one language to another. For example, the expression used for 'carelessly' in ASL means 'boring or unpleasant' in British Sign Language. [21]

Universality hypothesis

The universality hypothesis is the assumption that certain facial expressions and face-related acts or events are signals of specific emotions (happiness with laughter and smiling, sadness with tears, anger with a clenched jaw, fear with a grimace, or gurn, surprise with raised eyebrows and wide eyes along with a slight retraction of the ears, and disgust with a wrinkled nose and squinted eyes—emotions which frequently lack the social component of those like shame, pride, jealousy, envy, deference, etc.) and are recognized by people regardless of culture, language, or time. The belief in the evolutionary basis of these kinds of facial expressions can be traced back to Darwin's The Expression of the Emotions in Man and Animals. Reviews of the universality hypothesis have been both supportive [22] [23] and critical. [24] [25] Work in 2013 by Nelson and Russell [26] and Jack et al. [27] has been especially critical.

Support

Ekman's work on facial expressions had its starting point in the work of psychologist Silvan Tomkins. Ekman showed that facial expressions of emotion are not culturally determined, but universal across human cultures.

To demonstrate his universality hypothesis, Ekman ran a test on a group of the South Fore people of New Guinea, a pre-industrial culture that was isolated from the West. The experiment participants were told brief stories about emotional events (happiness, sadness, anger, fear, surprise, and disgust). After each story, they were asked to select the matching facial expression from an array of three faces. [28] The Fore selected the correct face on 64–90% of trials but had difficulty distinguishing the fear face from the surprise face. Children selected from an array of only two faces, and their results were similar to the adults'. Subsequent cross-cultural studies found similar results [29]

Criticism

Both sides of this debate agree that the face expresses emotion. The controversy surrounds the uncertainty about what specific emotional information is read from a facial expression. Opponents of the universality hypothesis believe that more general information is pieced together with other contextual information in order to determine how a person feels. [30]

One argument against the evidence presented in support of the universality hypothesis is that the method typically used to demonstrate universality inflates recognition scores. [25] Although each factor may contribute only a small amount to the inflation, combined, they can produce exaggerated scores. The three main factors are the following:

Evolutionary significance of universality

Darwin argued that the expression of emotions has evolved in humans from animal ancestors, who would have used similar methods of expression. Darwin believed that expressions were unlearned and innate in human nature and were therefore evolutionarily significant for survival. He compiled supporting evidence from his research on different cultures, on infants, and in other animal species. [35] :12 Ekman found that people from different cultures recognized certain facial expressions despite vast cultural differences, and his findings tended to confirm Darwin's initial hypothesis. [36]

Cross-cultural studies had shown that there are similarities in the way emotions are expressed across diverse cultures, but studies have even shown that there are similarities between species in how emotions are expressed. Research has shown that chimpanzees are able to communicate many of the same facial expressions as humans through the complex movements of the facial muscles. In fact, the facial cues were so similar that Ekman's Facial Action Coding System could be applied to the chimps in evaluating their expressions. [37] Of course, differences between the species' physical facial properties, such as white sclera and everted lips in chimps, would mean that some expressions could not be compared. [38]

Similarly, Darwin observed that infants' method of expression for certain emotions was instinctive, as they were able to display emotional expressions they had not themselves yet witnessed. [39] Facial morphology impacts expression recognition in important ways, and therefore, infant facial morphology may also serve some specific communicative function. These similarities in morphology and movement are important for the correct interpretation of an emotion. [40] Darwin was particularly interested in the functions of facial expression as evolutionarily important for survival. He looked at the functions of facial expression in terms of the utility of expression in the life of the animal and in terms of specific expressions within species. Darwin deduced that some animals communicated feelings of different emotional states with specific facial expressions. He further concluded that this communication was important for the survival of animals in group-dwelling species; the skill to effectively communicate or interpret another animal's feelings and behaviors would be a principal trait in naturally fit species. [35] :12–14 However, this suggests that solitary species such as orangutans would not exhibit such expressions.

See also

A boy displays an angry pout. Pouting boy in Shamar, Iraq.jpg
A boy displays an angry pout.

Related Research Articles

<span class="mw-page-title-main">Body language</span> Type of nonverbal communication

Body language is a type of communication in which physical behaviors, as opposed to words, are used to express or convey information. Such behavior includes facial expressions, body posture, gestures, eye movement, touch and the use of space. The term body language is usually applied in regard to people but may also be applied to animals. The study of body language is also known as kinesics. Although body language is an important part of communication, most of it happens without conscious awareness.

<span class="mw-page-title-main">Face perception</span> Cognitive process of visually interpreting the human face

Facial perception is an individual's understanding and interpretation of the face. Here, perception implies the presence of consciousness and hence excludes automated facial recognition systems. Although facial recognition is found in other species, this article focuses on facial perception in humans.

<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.

<span class="mw-page-title-main">Microexpression</span> Innate result of voluntary, involuntary, and conflicting emotional responses

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.

<span class="mw-page-title-main">Nonverbal communication</span> Interpersonal communication through wordless (mostly visual) cues

Nonverbal communication (NVC) is the transmission of messages or signals through a nonverbal platform such as eye contact (oculesics), body language (kinesics), social distance (proxemics), touch (haptics), voice (paralanguage), physical environments/appearance, and use of objects. When communicating, we utilize nonverbal channels as means to convey different messages or signals, whereas others can interpret these message. The study of nonverbal communication started in 1872 with the publication of The Expression of the Emotions in Man and Animals by Charles Darwin. Darwin began to study nonverbal communication as he noticed the interactions between animals such as lions, tigers, dogs etc. and realized they also communicated by gestures and expressions. For the first time, nonverbal communication was studied and its relevance questioned. Today, scholars argue that nonverbal communication can convey more meaning than verbal communication.

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">Eye contact</span> Form of nonverbal communication

Eye contact occurs when two people or animals look at each other's eyes at the same time. In people, eye contact is a form of nonverbal communication and can have a large influence on social behavior. Coined in the early to mid-1960s, the term came from the West to often define the act as a meaningful and important sign of confidence and respect. The customs, meaning, and significance of eye contact can vary greatly between societies, neurotypes, and religions.

Kinesics is the interpretation of body communication such as facial expressions and gestures, nonverbal behavior related to movement of any part of the body or the body as a whole. The equivalent popular culture term is body language, a term Ray Birdwhistell, considered the founder of this area of study, neither used nor liked.

<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.

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">Oculesics</span>

Oculesics, a subcategory of kinesics, is the study of eye movement, behavior, gaze, and eye-related nonverbal communication. The term's specific designation slightly varies apropos of the field of study. Communication scholars use the term "oculesics" to refer to the investigation of culturally-fluctuating propensities and appreciations of visual attention, gaze and other implicitly effusive elements of the eyes. Comparatively, medical professionals may ascribe the same appellation to the measurement of a patient's ocular faculty, especially subsequent a cerebral or other injury.

<span class="mw-page-title-main">Frown</span> Facial expression

A frown is a facial expression in which the eyebrows are brought together, and the forehead is wrinkled, usually indicating displeasure, sadness or worry, or less often confusion or concentration. The appearance of a frown varies by culture. An alternative usage in North America is thought of as an expression of the mouth. In those cases when used iconically, as with an emoticon, it is entirely presented by the curve of the lips forming a down-open curve. The mouth expression is also commonly referred to in the colloquial English phrase, especially in the United States, to "turn that frown upside down" which indicates changing from sad to happy.

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 the 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.

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. 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. 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.

Non-verbal leakage is a form of non-verbal behavior that occurs when a person verbalizes one thing, but their body language indicates another, common forms of which include facial movements and hand-to-face gestures. The term "non-verbal leakage" got its origin in literature in 1968, leading to many subsequent studies on the topic throughout the 1970s, with related studies continuing today.

Social cues are verbal or non-verbal signals expressed through the face, body, voice, motion and guide conversations as well as other social interactions by influencing our impressions of and responses to others. These percepts are important communicative tools as they convey important social and contextual information and therefore facilitate social understanding.

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 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.

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