Emotion

Emotions are often produced by stimuli that have high significance to the individual, and thus give rise to high bodily arousal, arousal meaning physiological response, often those related to fight or flight reactions.
There is controversy about whether it is the emotion (sadness) that elicits the physiological response
(eg crying), or the physiological response that elicits the emotion.


There have been a few different theories of emotion
Common Sense theory: Claims that the individual will first experience the stimulus (for example- See a bear), the perception will then occur (interpretation of stimulus -Danger), which will lead to an emotional state and this will cause the bodily arousal (pounding heart).
James Lang theory: Claims that it is the other way round and that the stimulus is followed by the perception of the stimulus, followed by bodily arousal and this leads to the emotional state (fear).
Cannon Bard theory: Claims that after the perception of stimulus, both the bodily arousal and the emotion will occur at the same time.
Schachter Cognition plus Feedback theory claims that the same physiological arousal accompanies all emotions but it is our own interpretation of the physiological arousal, that defines the emotion we feel. This is because emotions are subjective to the individual, happy sad angry all mean different things to each one of us but it is how we label our feelings which is important.
In order to understand how we process emotion it is important to look at the brain in more detail. It has been found that there are specific areas within the brain that have a role in emotion.
The amygdala is a collection of nuclei in the anterior temporal lobe and has been found to be heavily involved in emotion. In 1998 Le Doux called the amygdala the 'emotional brain'. There are several factors factors that provide evidence for the role of the amygdala in emotion. Firstly case studies with humans who have damage to the amygdala. It has been found that post  injury, humans have a reduced number of emotional behaviours and often exhibit a change in personality traits, such as being more aggressive and grumpy, suggesting an alteration in there emotional state. Secondly researchers have created experimental lesions in different species of animal and noted the behavioural changes both before and after surgery. Research with psychopaths has also found that damage to the amygdala has effected their ability to read facial expressions and thus there ability to understand emotion. This may account for their lack of empathy with there victims, since they do not understand what pain or fear look like. The amygdala has also been implicated in fear conditioning, it has been found that when pathways to the amygdala are damaged the animal subject can not learn fear conditioning, therefore reinforcing the role of the amygdala.
It has been found that the right hemisphere of the brain is more involved in emotional perception, particularly the orbito-frontal cortex. The majority of evidence again comes from human case studies of brain lesioned individuals. However both hemispheres have been found to be involved in emotional expression.