Emotional lateralization is the asymmetrical representation of emotional control and processing in the brain. There is evidence for the lateralization of other brain functions as well.

Emotions are complex and involve a variety of physical and cognitive responses, many of which are not well understood. The general purpose of emotions is to produce a specific response to a stimulus. Feelings are the conscious perception of emotions, and when an emotion occurs frequently or continuously this is called a mood.

A variety of scientific studies have found lateralization of emotions. FMRI and lesion studies have shown asymmetrical activation of brain regions while thinking of emotions, responding to extreme emotional stimuli, and viewing emotional situations. Processing and production of facial expressions also appear to be asymmetric in nature. Many theories of lateralization have been proposed and some of those specific to emotions. Please keep in mind that most of the information in this article is theoretical and scientists are still trying to understand emotion and emotional lateralization. Also, some of the evidence is contradictory. Many brain regions are interconnected and the input and output of any given region may come from and go to many different regions.

Some variations of right hemisphere dominance are...
a) The right hemisphere has more control over emotion than left hemisphere.
b) The right hemisphere is dominant in emotional expression in a similar way that the left hemisphere is dominant in language.
c) The right hemisphere is dominant in the perception of facial expression, body posture, and prosody.
d) The right hemisphere is important for processing primary emotions such as fear while the left hemisphere is important for preprocessing social emotions.

General lesions in the right hemisphere reduce or eliminate electrodermal response (skin conductance response ((SCR)) to emotionally meaningful stimuli while the lesions in the left hemisphere do not show changes in SCR response.

Subject SB-2046 had part of his right, prefrontal lobe removed because of cancer. While his IQ and a majority of other normal functions were unharmed, he had severely impaired decision-making skills especially when he had to consider immediate vs. future reward and punishment. His decisions were almost always guided by immediate reward or punishment and disregarded any long-term consequences. Researchers were incapable of conditioning patient SB-2046 to nonverbal stimuli containing emotional meaning (reward or punishment), but were able to condition the patient to verbal stimuli containing emotional meaning.

Most language production and processing occur in the left hemisphere while the majority of the emotional processing and production of emotion in speech occurs in the right hemisphere. Persons with schizophrenia usually have difficulty processing prosody. These patients also show a remarkable increase in lateralization towards the right hemisphere of both emotionally and non-emotional prosody rich speech. Also, a decrease in right-handedness led to an increase in the right hemisphere lateralization. This right hemisphere lateralization extends beyond prosody to many of aspects of language and speech processing in schizophrenic patients.

The two hemispheres have a complementary specialization for control of different aspects of emotion.
a) Left hemisphere primarily process "positive" emotions and right hemisphere primarily process "negative" emotions. A large portion of regions primarily in the right hemisphere are activated during aversive classical conditioning.