Facial expression refers to the motion and positioning of the muscles beneath the skin of the face.
These movements convey the emotional state of an individual to observers and are a form of nonverbal communication.
They are a primary means of conveying social information between humans.
People 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.
Beyond the added 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.
There is controversy surrounding the question of whether facial expressions are a worldwide and universal display among humans.
Facial expressions are vital to social communication between humans, and 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.
Facial 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 and are developed from the first pharyngeal arch.
There are two brain pathways associated with facial expression; voluntary expression, and emotional.
Voluntary expression travels from the primary motor cortex through the pyramidal tract (corticobulbar projections).
The cortex is associated with rules in emotion and social precepts that influence and modify expressions.
Cortically related expressions are made consciously.
Emotional expressions originate from the extrapyramidal motor system, which involves subcortical nuclei, a such genuine emotions are not associated with the cortex and are often displayed unconsciously.
Emotional expressions are demonstrated in infants before the age of two; they display distress, disgust, interest, anger, contempt, surprise, and fear: Infant displays of these emotions indicate that they are not cortically brain related.
Blind children also display emotions, proving that they are subconscious rather than learned.
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 facial expressions.
The lower portions of the face are controlled by the opposite cerebral hemisphere, causing asymmetric facial expression.
Because the right hemisphere is more specialized for emotional expression, emotions are more strongly expressed on the left side of the face,particularly for negative emotions.
The amygdala plays an important role in facial recognition: 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.
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.
What shapes a child’s cognitive ability to detect facial expression is being exposed to it from the time of birth, and themore 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 as early as the first few days of life.
Gender affects the tendency to express, perceive, remember, and forget specific emotions.
Angry male faces and happy female faces are more recognizable, compared to happy male faces and angry female faces.
Emotion residue is found that even when study participants attempt 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.
A 1988 study on the “facial feedback” hypothesis found that study participants mood was improved when they smiled. [12] However, this study later failed a large replication attempt.[13]
Memory for another individual’s face partly depends on an evaluation of the behavioural intention of that individual.
A person’s face, especially their eyes, creates the most obvious and immediate cues that lead to the formation of impressions.
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.
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.
Humans are one of the few mammals who maintain regular eye contact with their mother while nursing.
Eye contact regulates conversations, shows interest or involvement, and establishes a connection with others.
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; however, in western cultures this could be misinterpreted as lacking self-confidence.
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.
Facial expression is used in sign languages to convey specific meanings.
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, surprise with raised eyebrows and wide eyes along with a slight retraction of the ears, and disgust with a wrinkled nose and squinted eyes are emotions which frequently lack a social component of those like shame, pride, jealousy, envy, deference, and are recognized by people regardless of culture, language, or time.
People from different cultures recognize certain facial expressions despite vast cultural differences.
Infants’ method of expression for certain emotions is instinctive, as they are able to display emotional expressions they had not themselves yet witnessed.