Overview

Introduction

There are 6 types of major facial expressions:

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Fig. 1

From top left: happiness, sadness, surprise, anger, fear, disgust.

http://brainconnection.positscience.com/med/medart/l/amygdala.jpg

Fig. 2

The almond-shaped Amydala (fig. 2) in the brain is the first to respond to emotional events and it triggers a series of split second reactions within the brains emotional core. Wave of nerve impulses travel down the brain stem setting off an instantaneous visceral response throughout the body.

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Detecting emotions

Facial muscles are cues to emotions, and feigned emotions are different from genuine ones. So if you're upset, the emotion of happiness you portray is a feigned emotion. For working adults, since majority of them communicate through technology, 'emoticons' (fig. 3) are used to show their emotions. But, of course, there's no way to see if it's real.


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Fig. 3

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Effects of Facial Expressions

Expressions amplify and regulate emotions and the expressions shown, such as smiling, can affect emotions, for instance, feeling happy. In short, facial expressions that is shown can affect how the person feels.

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Interesting fact!

Females are...

• more superior at reading emotional cues and detecting lies, and
  
• more emotionally responsive, expressive and empathic

as compared to males.

Influences

Some might believe that they can hide their feelings, but the subtleties of emotions often give people away. So, what is it that influences people's emotions?

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Environmental influences

Although basic emotions seem largely innate, the influences of culture and learning modifies emotional expressions. The presence of other people often influences the intensity of emotional expression.

For example, Japanese students tend to be more expressive when they watch a film alone compared with unfamiliar peers.
However, the emotional expression of American students did not vary whether they were watching alone or with unfamiliar peers (Ekman, Friesen, & Ellsworth, 1972).

Also, gestures in different cultures mean different things, but, for facial expressions, they are universal, innate and social. A study was done and it showed that blind babies were able to exhibit social smiles at about the same age as sighted infants.

In addition, another factor that influences people's emotions is that cultures vary in how much expressions should be expressed.

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Individual differences

The overall levels of emotional reactivity is different between humans, and one source of individual difference appears to be the amygdala, mentioned above. The amygdala plays a crucial role in interpretation of emotion stimuli. In a study, when participants were shown photographs to elicit negative or neutral mood, those with higher amygdala activity in response to viewing negative photos reported more negative mood.

Gender also plays a part, as mentioned in the above post. Woman are more able to express their emotions more than man. (Fig. 1)


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Fig. 1

Theories

There are many types of theories regarding emotions, but in this blog, we'll identify a few.

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The James-Lange Theory

• Theory states that a sequence of events results in an emotional experience
• Our physical state becomes aware of a situation, which leads to an identification of subjective feelings. (fig. 1)


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Fig. 1

• Believes that pent-up anger will somehow make things worse, and when at its limit and released, any emotions from a person will be emptied.
• Studies regarding this theory showed that when participants were instructed to move their faces in a particular way, they reported feeling the emotions that they portrayed.
• For example, when asked to smile, they felt happy for no reason.
• But, studies also showed that expressing of emotions are more likely to enhance than reduce our feelings.

Real life example:
In a office setting, when the boss enters the common room, the sight of the boss illicit physical responses and thus the brain will interpret that response as fear.

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The Canon-Bard Theory

• Theory states that both the subjective and physical responses occur simultaneously and independently. (fig. 2)
• According to theory, the central nervous system has the ability to produce an emotion directly.
  

http://media.wiley.com/Lux/85/25285.ngr002.jpg
Fig. 2

Real life example:
In a office setting, when the boss enters the common room, the authority of the boss triggers subjective feeling of fear and physiological fight or flight response. Thus, workers will choose to stay in the same room or find an excuse to leave the room.

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The Schachter-Singer Theory

• Theory states that the stimulus first produces general arousal. Then, there would be a cognitive assessment done on the situation which allows a subjective feeling to be identified. (fig. 3)

Fig. 3

Real life example:
In a office setting, when the boss enters the common room, sight of boss initiate general arousal and the situation is accessed cognitively to find out what caused the arousal, and the the feeling is identified as fear.

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Contemporary Theories of Emotion

• States that highly specific physical response leads to unambiguous recognition by the cerebral cortex (fig. 4).
  
  
  http://www.morphonix.com/software/education/science/brain/game/specimens/images/cerebral_cortex.gif
  Fig. 4
  

• On the other hand, least differentiated physical signals produce general arousal, which require significant cognitive processing and evaluation in a manner consistent with the Schachter-Singer Theory.
• This model predicts that emotional response may range from immediate to delayed, based on the amount of cognitive processing required.
  

Real life example:
Sight of boss in home clothes in the streets initiate general arousal and a significant amount of cognitive processing is used to find out what caused the arousal and to evaluate feeling. Then, the feeling is identified as fear and workers avoid talking to their boss even though it's not a work day.

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In a nutshell!
Feelings are vital to our daily lives, as they enable us to experience the world and communicate with others. Just like when a person walks into his/her office and smiles, others would interpret it differently.

Biological

Emotional states are accompanied by complex, interacting physical responses that is unknown to us all.

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The Autonomic Nervous System

The autonomic nervous system (ANS) participates in the general arousal associated with emotional states and has two components, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).

When activated, the SNS prepares the body for emergency actions; it controls glands of the neuroendocrine system (thyroid, pituitary, and adrenal glands). Activation of the SNS causes the production of epinephrine (adrenaline) from the adrenal glands, increased blood flow to the muscles, increased heart rate, and other readiness reactions.
Conversely, the PNS functions when the body is relaxed or at rest and helps the body store energy for future use. PNS effects include increased stomach activity and decreased blood flow to the muscles.

Autonomic responses associated with negative emotions are stronger than those associated with positive emotions.

In the forebrain, there is the limbic system (fig. 1) and it includes the amygdala, the hippocampus, the cingulate gyrus, structures that are parts of the hypothalamus and more.


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Fig. 1

The word limbic means “border” and describes this system because its structures seem to form a rough border along the inner edge of the cerebrum.
Studies have associated the limbic system with such emotions as fear and aggression as well with as drives, including those for food and sex.

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Amygdala

As mentioned before, the amygdala is responsible for emotions and it participates in the active exploration of social environment and the interpretation of the results of that exploration.
Damage to the amygdala interrupts previously learned fear responses and prevents further learning about new sources of danger. Also, bilateral damage to the amygdala produces reduced emotionality.

In an experiment, researchers removed both temporal lobes in rhesus monkeys. Following recovery, the monkeys were:

• Tamer, having less intense emotions
• Oblivious to normal fear-producing stimuli
• Overly reactive to visual stimuli but cannot recognize familiar objects

This set of symptoms, whether observed in humans or monkeys, collectively became known as Klüver-Bucy syndrome.

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The Cingulate Cortex

Anterior cingulate cortex is the target of a number of pathways communicating information about physical pain.
It also participates in the processing of social pain, negative feelings associated with being socially excluded by others.

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The Cerebral Cortex

Frontal lobe damage is associated with a reduction in emotional feelings especially fear and anxiety.
An individual will became calmer if the frontal lobes are removed.
Left hemisphere is correlated with positive emotions while the right hemisphere is correlated with negative emotions.
Patients who suffer from damage to the left hemisphere are often depressed.
Patients who suffer from damage to the right hemisphere are often cheerful. The left side of the face is more expressive than the right side.

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Did you know?
We do not have “happy centers” and “sadness centers” in the brain. Widespread areas of the brain appear to be associated with each specific emotion, and areas associated with different emotions show considerable overlapping.

References

Ekman, P., Friesen, W. V., & Ellsworth, P. (1972). Emotion in the human face: Guidelines for research and an integration of findings. London: Pergamon Press.

Freberg, L. A. (2010). Discovering Biological Psychology. (2nd ed.). California: Wadsworth Cengage Learning.