Violence: Are Humans Bad To The Bone?

By Gemma Tarlach | September 28, 2016 12:00 pm
SMACK! POW! BLAM! Humans evolved along a particularly violent branch of the tree of life.

SMACK! POW! BLAM! Humans evolved along a particularly violent branch of the tree of life.

Sorry, peaceniks. New research that takes an innovative approach to charting the evolution of lethal violence has found that Homo sapiens evolved from a particularly brutish branch of mammals. A proclivity for smashings and bashings is in our DNA. Before you punch something because this news upsets you, though, take heart: the researchers also found that our propensity for killing each other can be mitigated.

Trying to figure out why humans are prone to killing other humans has bedeviled many scientists and philosophers along the way. Part of the problem is that the very topic of violence involves a mosh pit of potential influences that are tough to pull apart in any kind of scientifically robust way.

Researcher José María Gómez and colleagues took a novel approach to cutting through all the noise by turning to phylogeny, which charts how a species develops and then radiates out into different species.



What they found in a nutshell: Homo sapiens are part of an especially violent lineage that goes back millions of years.

Across the mammal spectrum, the rate of lethal violence against a member of the same species is about 0.30 percent, or a 1 in 300 chance of being killed by one of your own kind. For the ancestor of great apes (including us), it was 1.8 percent. And for humans at the origin point of our species, the rate bumps up to 2 percent, or a 1 in 50 chance of being murdered.

Our species is, in other words, at the high point (such as it is) of a steady increase in intraspecies lethal violence that has been going on for about 100 million years.

Severe fracturing in a 10,000 year-old skull from Kenya is evidence of lethal violence among humans. Credit: Marta Mirazon Lahr

Severe fracturing in a 10,000 year-old skull from Kenya is evidence of lethal violence among humans. Credit: Marta Mirazon Lahr

Wait a minute, you’re grumbling (I can actually hear you), how could they possibly figure out what the rate of ancestors killing ancestors was when we’ve got little more than a couple shoeboxes full of fossils from back in the day? And yes, there is some art and estimation involved in reconstructing these rates. But there is a lot of legitimate number-crunching and sophisticated modeling going on as well.

The researchers, whose work was published in Nature today, collected data from more than 4 million deaths among more than 1,000 species of mammal, from shrews to whales, as well as 600 human populations dating from our earliest known hunter-gatherer days till now.

Using modeling methods similar to those which trace the evolution of specific physical traits, the team charted the prevalence of lethal violence within each species.

A few patterns emerged: Some fairly diverse types of animals, notably whales and bats, get along with their own kind just fine, thanks very much. Also, herbivores in general were more kumbaya about it all.

But the researchers found that the more social and territorial a species was, the more prevalent lethal member-against-member violence.

It makes sense: if you’re living with other members in a social group, there are simply more opportunities to get in a bloody tiff. And if you’ve got limited resources, or you’re bent on protecting or expanding your neck of the woods, you’ve got more motive to conk a competitor on the noggin. Hey, I watch Law & Order reruns. Motive and opportunity, man. It’s always been about motive and opportunity.

Intraspecies lethal violence among non-human mammals comes in many colors. The lighter the color, the less lethally violent the species is towards other of its kind. And the closer the color is to red, the more likely blood will be shed. Credit: Gomez, et al.

Intraspecies lethal violence among non-human mammals comes in many colors. The lighter the color, the less lethally violent the species is towards others of its kind. And the closer the color is to red, the more likely blood will be shed. Humans (red triangle, upper left) hail from a particularly murderous lineage (note the concentration of yellows, oranges and reds among primates). Credit: Gomez, et al.

While you’re looking at the Circle of Life (and Death) above, you’re probably noticing that primates aren’t the only branch of the family tree with homicidal tendencies. Unsurprisingly, researchers found that non-primate predatory carnivores also tend to be more violent towards each other, particularly, again, those living in social, territorial groups.

So much for hakuna matata...lions and other predatory carnivores have above-average violent tendencies to other members of their species. Credit: Walt Disney Pictures

So much for hakuna matata…lions and other predatory carnivores have above-average violent tendencies toward other members of their species. Credit: Walt Disney Pictures

Can’t We All Get Along?

Before you despair too much, though, the second part of the research offers some hope. The researchers looked at rates of lethal violence within the hundreds of human populations studied and how they corresponded to the type of society the individuals were living in. The team found that things got particularly bloody around 1,000 BC but, in the last 500 years or so, we as a species have cleaned up our act quite a bit.

The spike in carnage, roughly at the start of the Iron Age, corresponds to a period when a sizable chunk of our species quit the hunter-gatherer game or left small settlements for comparatively larger urban areas. It’s also a time when organizing states really ramped up the competition for territory. Yep, more of us living in closer quarters and vying for the same resources and territory. Motive and opportunity.

Over the last century or so, however, the decrease in lethal violence that started around 500 years ago has accelerated. In societies today with legal systems and law enforcement (“two separate yet equally important groups…”) and, just as important, a culture that rejects violence, murder rates are less than 1 in 10,000.

So, while today’s study makes a solid case for us being inherently more violent than the mammalian average, the researchers also showed that societal systems and cultural norms can keep that innate smash-bashiness in check.

 

Caption: MemeGenerator.Net

Caption: MemeGenerator.Net

CATEGORIZED UNDER: Living World, top posts
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  • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

    People kill people (and themselves) when appetites exceed resources, . Capitalism maximizes resources, socialism minimizes resources, feudalism’s massive infantry engagements remove appetites, and religion bans appetites, all with disproportionate managerial reward,

    Allow people to live their own lives and defend their earned assets with few central constraints and no mandatory charity. Amassing wealth loses pathology when government is not stealing it from you to reward Diversity! and its managers.

    decrease in lethal violence that started around 500 years ago has accelerated” because targets can now shoot back. Imposed morality is murderous. Encourage ethics and bow-legged women.

    • SFM

      The pursuit of Capital has lead to more violence and conflict than any other element, besides Religion, which is a defacto enforcer for those who Control the Machine, You sound like a G-dless Soulless machine yourself!

      • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

        Youtube v=v4rY52SWklc
        I am happier than you each Sunday – with better net retained assets.

        • SFM

          I’m sure you are. As my wonderful Grandmother used to say; Where there’s no sense there’s no feeling! I would venture your the type she was speaking of. For the record Sunday is just another day to me, I observe the Sabbath. As far as assets are concerned, I have a Beautiful Highly educated Wife, Three wonderful productive Children and Everything I need for happiness and success and I Ain’t talking about Money and or Possessions, of which we are blessed. All thanks be to G-d!
          Hard hearted and stiff necked people are what’s wrong with this World and the Culling can not come soon enough. Suggest you find a Rock to Hide under as your type will be first to GO! Shalom Uncle Al.

          • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

            President Barack Obama, Roanoke, VA, 13 July 2012: “If you’ve got a business. you didn’t build that. Somebody else made it happen.”

            Trump for President – no wannabe crooks in the White House..

          • OWilson

            “Don’t let anybody tell you it’s corporations and businesses that create jobs,” – Hillary Clinton

            How did America come to this?

          • J.L. Banks

            Not all of us think in dichotomies…dichotomies such as “Hillary vs. Trump”. I am a Bernie fan, but I would certainly take Hillary over Trump.

          • J.L. Banks

            Right, no wannabe crooks, just outright con-artist idiots who know nothing about politics and are only out for personal aggrandizement 4 prez!

            Well, you got your wish…

          • Paul Johny

            Praise the lord

        • Paul Johny

          Nope you are not .Remeber the relegious peole have god to go to ..Always they have a hope ..Sometimes you think you are smart ..But you might be just missing a critical part of brain where you can have feelings and understand higher power exist. You think by gaining assets you net worth is going to improve ..Happiness is something else .. You need to use your own brain to discover higer power exist .best of luck , peace and thank you

    • John Deckenbach

      You are so very wrong. Capitalism inspires greed and eliteism which both inspire sadism. The increase in civil violence is due to a decrease in social equality through wealth and money. And the everyday man is sick of playing masochist to the rich. It inspires anger.

      • J.L. Banks

        Yes, thank you!

    • J.L. Banks

      Socialism and Capitalism are not mutually exclusive…in fact, they almost always coexist in modern societies. The more Socialism based European nations tend to be far less violent than the USA, which is more overtly capitalistic. So while I don’t disagree with your concept of the motivation for violence in humans, I do disagree with the political correlations you’ve drawn.

      You seem to be Libertarian from your post. But I don’t think most of us could really exist in a fully Libertarian society, nor would most want to, as we appreciate services taxes bring us such as: police, fire-fighting departments, education, and, in most countries, healthcare.

      If we all work together we will see less discord. The data seems to back up such conceptions.

  • SFM

    And this is some type of Surprise?

  • joseph2237

    Actually the violence began to stop 2000 years ago when Christ stood up to the Roman Empire. Imagine the power of idea of peace in a world where killing was common place and in most cases justified because you could do it.

    I certainly agree with the conclusion that we descended from a violent species in a violent world. We like to think we were skilled and we adapted to a violent world with brain power rather than murdering our way through the pages of history to end on top of the food chain.

    • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

      Actually, Europe has seen the most peace these last 70 years after the last world war, during a time of decreasing religiosity. And Christianity brought inter religious conflicts even when Constantine was the Christian emperor–Christians persecuting each other and pagans and Jews, with Europe seeing plenty of violence for the last two millennia.

      • OWilson

        The passenger plane you and your family are on makes an emergency landing!

        “Oh dear, Martha, I hope we didn’t land in the middle of one of those christian countries!”

        • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

          Probably the right reaction during a lot of European history.

          • OWilson

            The most successful form of government ever formed in the history of the world, in terms of benefit to the average citizen, was founded on Christian religious principles, as in “In God We Trust”.

            It was the social glue that held your country together. (for a while!)

          • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

            The U.S. was founded on a lot of different principles. The Founders were horrified by all the religious wars of Europe and favored no religious tests of office. “In God We Trust” was added in the 1950s during America’s Anti-Commie Cold War period. Also, in so far as belief in God can hold a nation together, it was the Confederate Nation that added mention of “God almighty” to their new Confederate Constitution just prior to the Civil War during which more U.S. soldiers died than in all the wars afterwards including 2 World Wars, Korea and Vietnam. The northern legislature tried to add mention of “God almighty” to the North’s older original Constitution, but they decided not to make any changes to the North’s Constitution. The South during the Civil War in comparison viewed themselves as God’s holy and new chosen nation. And they lost the war.

          • OWilson

            Well said!

      • joseph2237

        Right but a lot of ethnic cleansing has gone on along side the peace around the world and usually it was religious motivated. Most religions feel compelled to help God play God by being judge, jury, and executioner of their brother and fellow man. None of which resembles Christ. When you look across the world and all it’s miss givings, traps of vise, crime, corruption, lies, betrayals you can get a fuller meaning in the words that our path to heaven is through the Christ. Beside most Christians absolutely fear death even as they say they believe in God. Albert Camus gets the last word: I shall tell you a great secret my friend. Do nor wait for the last judgement, it take place every day.

    • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

      Christianity taught love but also the demonization of enemies in quite a literal fashion, a mixed bag.

      • joseph2237

        Christ and Christianity, in case those of you missed it, are two separate things. Christ was a giver, Christianity are takers. Christ preached Love and Peace, Christianity preaches fear and retribution. Christ preached turn the other cheek and forgiveness, The Christianity preached isolationism demonization. Christ and the church are as far away from each other as heaven and hell are.

        • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

          Actually, Christ was into a literal belief in demons, look at the earliest Gospel, Mark.

          And Christ was not merely into “love” but used predictions of a soon coming worldwide judgment, and threats of eternal vengeance, and threats of demons to gain followers, and also preached that one should become members of his cult above all, willing to die for it rather than rejoining one’s own family. Very cultish.

        • http://www.infidels.org/library/modern/ed_babinski/babinski-bio.html EdwardTBabinski

          There is a book that lays out a scholarly case that Jesus was not simply into love and peace. The book if by religion Prof. Hector Avalos, and is titled The Bad Jesus. Check out some of the sections that you can read for free online via amazon or google books.

  • Mike Richardson

    Tribalism encourages us to not engage in violence against those we perceive to be in our family or larger religious/national/political group, but unfortunately can encourage it against any perceived “other.” Only as we begin to look beyond the artificial differences we create, and see our common humanity, can we begin to truly curb our worst impulses towards violence.

  • Koekjevan

    Go study human behavior and it’s environment. We are not good or evil, we are both “2 sides of the same coin”. Like water that can be still or come as a wave, it is still te same water. If you want to breed violence then stimulate despair, greed, envy, inequality “or this current society will do just fine” If we want honesty, love, creativity, peace and so on… flower it. Do I need to explain why starvation leads to despair?

  • John Deckenbach

    The violence mankind shows may not be innate to them. What is natural to us, and what most other mammals cannot do is feel deep emotions and make an effort to sort them and understand them. Our own subjective conscious makes violence an option which we can ration beyond our natural instincts for violence. Violence becomes a solution to many problems for mankind, when violence solves a great many less purposes to animals besides protection, fighting for mates or feeding themselves. It is our human condition that creates a need for violence way beyond what our genes are responsible for. Humans wants to believe that people are naturally violent and need to learn empathy, but it may just be that we are born with empathy, and learn violence as an option of solving any number of issues not even related to our survival like who wins a barfight. Our violence is rarely related to our survival, and more driven by our subjective wants.

    • J.L. Banks

      I find your post very poignant. I do think however that there is potentially a small minority of humans who are born without the capability for empathy. Certain abnormalities in the limbic system can render one incapable of empathy and compassion, and those can be due to genetic anomalies, head trauma, hypoxia due to various causes, etc.

      I really enjoy reading your thoughts about how our higher reasoning can actually encourage some of us to resort to violence. I believe you are correct. Reason without empathy/compassion can be an extremely dangerous combination.

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