A team of researchers at the Vanderbilt University in the United States has carried out the study and found it is the human brain which processes aggression as a reward much like sex, food and drugs.

"We have found that the 'reward pathway' in the brain becomes engaged in response to an aggressive event and that dopamine is involved. It's well known that dopamine is produced in response to rewarding stimuli such as food, sex and drugs of abuse. What we have now found is that it also serves as positive reinforcement for aggression," the ScienceDaily quoted lead researcher Maria Couppis as saying.

The researchers came to the conclusion after analysing the involvement of brain in aggression on rodents.

For the experiments, a pair of mice -- one male, one female -- was kept in one cage and five ‘intruder’ mice were kept in a separate cage. The female mouse was temporarily removed, and an intruder mouse was introduced in its place, triggering an aggressive response by the ‘home’ male mouse.