Are humans evolutionarily prone to violence? Steven Pinker argues in his novel The Better Angels of Our Nature that we were much more violent in the past, but we became less violent as civilization advanced. Biologist Edward O. Wilson argues that we are not evolutionary prone to violence and war, but rather our innate sense of morality and group loyalty resulted in tightly bound tribes that gave rise to conflict and war. Frans de Waal believes that we are inclined towards empathy and altruism, not war. Anthropologists Douglas Fry and Brian Ferguson believe the fossil record demonstrates that we became more violent after we civilized due to money, power, resources. Clearly this is a hot topic for debate. Let us see what our evolutionary story says about human violence.
A View from the Primates
Some researchers have looked into primate violence history to see if an inherent predisposition for violence exists in human nature. These researchers determined that severe aggression only makes up about 1% of all primate activity and that lethal violence is even more rare. There is no real evidence for male-female aggression in primates and conflicts are often solved by negotiations or avoidance rather than violence. In general, extreme violence is not a trait found in our ancestors… expect for certain species of chimpanzees. Eastern chimpanzees males are aggressive towards females and coerce them into certain activities, but Western male chimpanzees do not exhibit the same behavior. Both Eastern and Western chimps perform border patrols in their territories and act violently towards members of other communities if they come too close. Additionally, chimp males and females have been witnessed killing infants of their own and other communities. Bonobos, another species of chimpanzees, do not engage in border controls or infant homicide. From this evidence, scientists cannot conclude that human violence stemmed from primate, or specifically chimpanzee, origins.
Violence in Our Bodies
One major misconception about testosterone is that it enhances violence and aggression specifically in males. In actuality, testosterone is present in both males and females. It is produced in both genders during times of acute-stress because it increases muscle activity and lowers sensitivity to pain. Increased levels of testosterone does give individuals an edge in competitive situations.
Extreme Violence- Ancient or Modern?
Although modern forager groups cannot give us a true insight into the past, they do help us better understand our history. Anthropologist Doug Fry and psychologist Patrick Soderberg researched extreme violence in 21 modern mobile forager societies and noted 148 instances of extreme violence. They found that most instances of lethal aggression were interpersonal and could not be labeled as forms of war. Most forager societies and societies in general favored positive, non-aggressive social interactions.
Do aggressive males have more success with females? This is an important question to ask, because the answer may shed light on the increase in violence we see today. One study was conducted on the Yanomamo people in the Amazonian region. In this society, a man is labeled a “unokai” if he has killed another person in a raid or a fight. These men have 2.5 more wives than non-unokai people on average. While this may lead you to believe that violent males do have more success with females, there is a problem with the study. Unokai were not compared with men of the same age because on average unokai are 10.4 years older than non-unokai. This age difference also contributes to unokai having more wives. The Waorani, a South American society, was also researched for their aggressive behaviors. This society has the highest rate of homicide out of any small society ever researched. Contrary to popular beliefs, the aggressive men did not have more wives or children than the calmer men. Therefore, the question as to whether aggressive men have more success with females is still unanswered.
The fossil evidence we have for violence and war is inconclusive. Researchers are unable to determine if broken bones in fossils from 500,000 years ago were due to people accidentally falling off a cliff or from acts of violence. This is due to the fact that weapons at the time were unaltered rocks and sticks, so marks on the bones of someone falling off a cliff would look the same as someone beaten with a weapon. However, around 15,000 years ago we start to see concrete evidence for an increase in violence. The Jebel Sahaba site from 14,000-12,000 years ago shows evidence that 24/59 bodies found show evidence of traumatic violence. Researchers found stone points and arrow heads embedded in skeletons as well as missing limbs. Before this time period there were little to no signs of extreme violence, but it is at this time that we see violence begin to increase. Evidence was still relatively rare, but around 6,000-7,000 years ago we see many more examples of coordinated large-scale killing in places like Talheim and Schletz in Germany. Hundreds of murdered individuals were discovered in these places; Talheim is even nicknamed the “Death Pit” for this reason.
“Human culture was not characterized by a high incidence of either homicide or warfare compared to the modern era. However, over the last 5,000 to 10,000 years, the pace and intensity of this type of violence markedly increased” (155-156)
Creativity gave rise to violence. Human development paved the trail for class conflict. We created societies, stored resources, claimed properties, and divided labor. All these creative developments led to increased inequalities and therefore the incentive for intergroup conflict and violence. Humans learned to master survival through collaboration and cooperation and those skills led to a mastery of conflict and division. Humans became too good at innovating and creating, which led to the emergence of violence.
“Our capacity for war emerged from the capacity for peace” (162)