A new study (by José Maria Gómez et al) challenges Steven Pinker’s rosy picture of the state of the world. Science magazine reports: Though group-living primates are relatively violent, the rates vary. Nearly 4.5% of chimpanzee deaths are caused by another chimp, for example, whereas bonobos are responsible for only 0.68% of their compatriots’ deaths. Based on the rates of lethal violence seen in our close relatives, Gómez and his team predicted that 2% of human deaths would be caused by another human.

To see whether that was true, the researchers dove into the scientific literature documenting lethal violence among humans, from prehistory to today. They combined data from archaeological excavations, historical records, modern national statistics, and ethnographies to tally up the number of humans killed by other humans in different time periods and societies. From 50,000 years ago to 10,000 years ago, when humans lived in small groups of hunter-gatherers, the rate of killing was “statistically indistinguishable” from the predicted rate of 2%, based on archaeological evidence, Gómez and his colleagues report today in Nature.

Later, as human groups consolidated into chiefdoms and states, rates of lethal violence shot up — as high as 12% in medieval Eurasia, for example. But in the contemporary era, when industrialized states exert the rule of law, violence is lower than our evolutionary heritage would predict, hovering around 1.3% when combining statistics from across the world. That means evolution “is not a straitjacket,” Gómez says. Culture modulates our bloodthirsty tendencies.

The study is “innovative and meticulously conducted,” says Douglas Fry, an anthropologist at the University of Alabama, Birmingham. The 2% figure is significantly lower than Harvard University psychologist Steven Pinker’s much publicized estimate that 15% of deaths are due to lethal violence among hunter-gatherers. The lower figure resonates with Fry’s extensive studies of nomadic hunter-gatherers, whom he has observed to be less violent than Pinker’s work suggests. “Along with archaeology and nomadic forager research, this [study] shoots holes in the view that the human past and human nature are shockingly violent,” Fry says. [Continue reading…]