Violence is found throughout recorded human history, leading some researchers to conclude that we crave it, that it’s in our genes and affects reward centers in our brains. However, going back millions of years, evidence suggests our ancient human ancestors were more peace-loving than people today, though there are signs of cannibalism among the earliest pre-history humans.
A study in 2008 concluded that humans seem to crave violence just like they do sex, food, or drugs. The study, reported in the journal Psychopharmacology, found that in mice, clusters of brain cells involved in other rewards are also behind their craving for violence. The researchers think the finding applies to human brains.
“Aggression occurs among virtually all vertebrates and is necessary to get and keep important resources such as mates, territory and food,” said study team member Craig Kennedy, professor of special education and pediatrics at Vanderbilt University in Tennessee. “We have found that the reward pathway in the brain becomes engaged in response to an aggressive event and that dopamine is involved.”
Many researchers believe violence in humans is an evolved tendency that helped with survival.
“Aggressive behavior has evolved in species in which it increases an individual’s survival or reproduction, and this depends on the specific environmental, social, reproductive, and historical circumstances of a species. Humans certainly rank among the most violent of species,” says biologist David Carrier of the University of Utah.