Study leader and archaeology Professor Mark Allen says there are two views related to the origins of violence and warfare in humans - one that earlier humans were peaceful and lived in harmony, and another that there has always been competition for resources, war, and violence. This second view is confirmed in Allen's study of prehistoric hunter-gathers in central California.
     Using an archeological database of human burials of remains from thousands of individuals going back more than 1,000 years, Allen and his colleagues looked at the marks from physical traumas, comparing that evidence with the palaeo-environment and the way those communities were organised socially. They found that California had the highest population density in all of North America, with lots of small groups living in close proximity. There were approximately 100 different languages spoken in California at the time.
     Allen says that: "When people are stressed out and worried about protecting the group, they are willing to be aggressive. Violence is about resources for the group."
     The data show how the scarcity of resources and violence correlate. On average about 7 percent of the population at that time had evidence of forced traumas: 5 percent for females, and 11 percent for males - according to Allen, a level of violent trauma not even reached during World War 2.
     Allen says his research on the origins of violence and warfare speaks to what is happening in modern times: "It's important to study it because if we are ever going to have hope of stopping it, we have to know the cause. If we want to reduce conflict, we need to figure out what to do about resource stress."

Edited from ScienceDaily (17 February 2017)