are also inhabited by humans, are they not? So we can say that peacefulness is also an intrinsic part of human nature.

It seems that there are a lot of "studies" lately claiming that both tribalism and violence are the true biological natures of human beings, based on comparisons to our animal relatives and pre-historic ancestors. This study includes historical periods, too.

The last 100 years includes WW2, with its genocides, combat deaths around the entire globe, bombings of civilians in Berlin, London, Nagasaki, and Hiroshima. Also, independence wars of former colonies, and numerous acts if terrorism (Turkey, Israel, Africa). So pardon my skepticism about them as peaceful years.

Archaeological evidence indicates widespread trade in prehistoric as well as historic time, all around the globe. It showd raw materials and finished products far from their places of origin, e.g. food items, rocks and minerals, carved objects, jewelry, etc. Intermarriage cemented ties between different tribes and nations. This means cooperation and trade as well as war and killing. Trade with "the other" promotes peace and vice versa.

Animal comparisons with our closest relatives, chimps and bonobos, indicate that the cooperative, peaceful side of human nature is just as biologically intrinsic to us as war and killing. All 3 of us descend from an older common ancestor, but branched off from it to become separate species.

Chimps fight wars of extinction against other troops of chimps. They kill infants in their own troop and sometimes eat them. But they also cooperate among each other in common interests. Even among chimps, though, the degree and frequency of violence varies between troops.

Bonobos look like small chimps, but are a separate species from them. They are not inclined to genocidal wars like chimps. They resolve disputes more often by negotiations, often mediated by females. They are not prone to infanticide. They have been known to shun and exclude members that are too violent or domineering. But they are capable of killing, just less often, less inclined to it than chimps.

Humans, as close relatives to chimps and bonobos, sharing a common ancestor, also share traits in common, toward peaceful negotiations AND toward belligerent violence.

Cooperation, negotiation, peace, and acceptance/tolerance of differences are not artificially imposed behaviors on our intrinsic natures by civilization. They are intrinsic traits themselves that make the development of civilization possible in the first place.

"The medieval period was a particular killer, with human-on-human violence responsible for 12 percent of recorded deaths. But for the last century, we’ve been relatively peaceable, killing one another off at a rate of just 1.33 percent worldwide. And in the least violent parts of the world today, we enjoy homicide rates as low as 0.01 percent."

to the last century, whether meaning all of the 20th century, or the past 100 years from 1920 to present, must include the killings from the wars I mentioned, e.g. African and ME nations fighting for independence from colonial rulers; chronic war and terrorism in Israel; India's struggle for independence; Hindu vs Muslim in India; lynchings in the US.

Ideologies of tribalism and social Darwinism were behind a lot of those killings. Emphasizing those ideologies as the true biological nature of human beings, based on our animal relatives, encourages that kind of behavior and thinking at the expense of other qualities that are equally part of our biological inheritance through evolution.

That's my main point because I am disturbed by how often lately I am coming across this idea in lop-sided "studies" and conversations with people who buy into the notion that hostility and distrust of "the other" is our true nature. That notion leads people to conclude that other natural human qualities like negotiation, compassion, peace, cooperation, and mutually beneficial interactions across social and cultural boundaries are artificially imposed on people by civilization, abd that they can be easily discarded, and should be.

RE: the killings of the Middle Ages. That term implies European history from the fall of Rome to early modern times. There were many other cultures around the world existing in the same time period. Some emphasized peace and the value of life and others, not so much.