I play pond hockey. After we whack the puck around a while, and we’re soaked in sweat and sagging, I shout, “Next goal wins!” Then, no matter how exhausted I am, I skate like a maniac to score that last goal.

So are humans innately aggressive? Of course we are, and some of us more than others. My aggression emerges not only in hockey games but also in spats over whether war—not just aggression, or violence, but deadly group violence--has deep evolutionary roots.

Prominent skeptic Michael Shermer recently tweeted a report on a 10,000-year-old massacre in Africa, which he counts as evidence for the deep-roots theory. Shermer wrote, “Sorry blank slaters & Peace & Harmony Mafia.”

That phrase, Shermer explained in a follow-up post on Social Evolution Forum, refers to those “who adhere to the blank slate theory of human nature and those rather aggressive anthropologists who insist that war is a recent invention and that our ancestors lived in relative peace and harmony with one another and nature.” [See Postscript on the ironic origins of “Peace & Harmony Mafia.”]

This is a common tactic of deep-rooters, to suggest that if you reject the war-is-innate theory, you must be a blank slater who rejects all biological predispositions and thinks our ancestors were peaceful “noble savages.” “Rather aggressive anthropologists” is Shermer’s sly way of implying that, if you aggressively oppose the deep-roots theory, you contradict yourself.

I have never disputed—nor do I know any scholar who disputes--that humans have genetically-based capacities for aggression, anger, vengeance. I also accept that our hominid ancestors, and especially males--whose aggression is much more likely to culminate in violence--occasionally killed each other fighting over females, food or other “resources.”

What I dispute is that we have an innate predisposition for war--or, as anthropologist Richard Wrangham describes it, “lethal coalitionary aggression”--dating back millions of years to our common ancestor with chimpanzees.

Shermer claims there is “massive,” “copious” evidence that “warfare—or violent conflict—was part of our Environment of Evolutionary Adaptedness (EEA) and thus part of our evolved nature.” Actually, evidence of group violence dates back only about 12,000 years.

Do our predispositions toward aggression underpin outbreaks of lethal violence, including war? Of course they do, but that doesn’t mean war is innate, any more than it means hockey is innate. Consider the analogy between aggression and language.

Noam Chomsky and others have compiled copious evidence that our capacity for language is innate, evolving more than one hundred thousand years ago. Our “language instinct” (Steven Pinker’s phrase) clearly enabled the independent inventions of written communication by various societies thousands of years ago. But that does not mean reading and writing are innate. These are recent cultural innovations, and so is war.

Like writing, war emerged independently among early societies--including simple ones, like hunter-gatherers--toward the end of the Paleolithic. Then war spread like a virus, infecting even societies that wanted no part of it. If your neighbor attacks, you can either flee, surrender or fight back.

Deep-rooters often accuse critics of confirmation bias, but consider how Shermer treats a recent analysis of Homo naledi skeletons found in a South African cave. Shermer conjectures that the hominids were victims of “war and murder.”

The anthropologist and Homo naledi researcher John Hawks accuses Shermer of “murdering the facts.” None of the bones, Hawks points out, show “any traces that indicate that the individuals met a violent end. “

Shermer suggests that my “tireless” criticism of the deep-roots theory is driven by emotion. He’s right, in this sense: I loathe war, and I loathe the deep-roots theory, because I believe it contributes to the fatalistic acceptance of our era’s militarism.

My most recent survey at Stevens Institute of Technology found that 124 out of 142 students, or 87 percent, believe war will never end. Pessimists often defend their outlook with some version of the deep-roots claim.

If the deep-roots theory were empirically validated, I would explain to my students that we can and do overcome biologically-driven impulses. But the deep-roots theory does not stand up to scrutiny. That is the main reason why I tirelessly criticize it.

I’d much rather be playing hockey.

Postscript: There’s an irony embedded in the colorful phrase “Peace & harmony mafia.” Shermer credits anthropologist Johan M.G. van der Dennen with coining the phrase and political scientist John Mueller with inspiring it. Mueller is one of my favorite war scholars. I quote him in The End of War and on this blog, and I am bringing him and Mark Stewart to my school March 30 to talk about their new book on the failures of U.S. counterterrorism, Chasing Ghosts.

Shermer and van der Dennen quote from a 1991 essay in which Mueller complains about peace advocates who insist that war will end only if we first achieve “harmony, inner tranquility, cooperation, goodwill, love, brotherhood, equality, and/or justice.” Mueller rejects this notion. To achieve peace, he asserts, “people do not necessarily have to become admirable, nor do they need to stifle all their unpleasant instincts and proclivities; they merely need to abandon the rather absurd institution of war as a method for dealing with one another.”

I agree. In fact, I have argued that “the end of war does not mean the end of all conflict, as skeptics often imply.” I also like Mueller’s description of war as an  “institution.” Mueller elaborates on this idea in a 2009 essay on the decline in war-related deaths since World War II.

Mueller calls war “merely an idea, an institution that has been grafted onto human existence… And the institution may be in pronounced decline, as attitudes toward it have changed, roughly following the pattern according to which the ancient and once-formidable institution of formal, state-sponsored slavery became discredited and then obsolete.”

Again, I agree. Shermer says “blank slaters” view war as “a learned phenomenon that carries the inference of cultural determinism, which means we can change war by changing culture.” That’s actually a fair characterization of my view of war, and of Mueller’s.

This is also the view that anthropologist Margaret Mead--Queen of the blank slaters & Peace & Harmony Mafia—set forth in her 1940 essay “Warfare Is Only An Invention—Not a Biological Necessity.”

Shermer and other deep-rooters should read Mueller and Mead more carefully. Who knows. Maybe they’ll end up joining the Peace & Harmony Mafia.

Further Reading:

10,000-Year-Old Massacre Does Not Bolster Claim That War Is Innate.

Quitting the hominid fight club: The evidence is flimsy for innate chimpanzee–let alone human–warfare.

New Study of Foragers Undermines Claim That War Has Deep Evolutionary Roots.

New Study of Prehistoric Skeletons Undermines Claim that War Has Deep Evolutionary Roots.

Survey of Earliest Human Settlements Undermines Claim That War Has Deep Evolutionary Roots.

Chimp Violence Fails to Support Deep-Roots Theory of War.

Margaret Mead’s War Theory Kicks Butt of Neo-Darwinian and Malthusian Models.

RIP Military Historian John Keegan, Who Saw War As Product of Culture Rather than Biology.

War Is Our Most Urgent Problem; Let's Solve It.