The American military historian S.L.A. Marshall was perhaps best known for his book Men Against Fire: The Problem of Battle Command in Future War, where he argued that American military training was insufficient to overcome most men’s natural hesitation to take another human life, even in intense combat situations. Dave Grossman is a modern military author who draws much of his conclusions from the initial work of Marshall. Grossman’s case is presented in his book On Killing: The Psychological Cost of Learning to Kill in War and Society, which was reviewed by Robert Engen in an older issue of the Canadian Military Journal:

As a military historian, I am instinctively skeptical of any work or theory that claims to overturn all existing scholarship – indeed, overturn an entire academic discipline – in one fell swoop. In academic history, the field normally expands and evolves incrementally, based upon new research, rather than being completely overthrown periodically. While it is not impossible for such a revolution to take place and become accepted, extraordinary new research and evidence would need to be presented to back up these claims. Simply put, Grossman’s On Killing and its succeeding “killology” literature represent a potential revolution for military history, if his claims can stand up to scrutiny – especially the claim that throughout human history, most soldiers and people have been unable to kill one another.

I will be the first to acknowledge that Grossman has made positive contributions to the discipline. On Combat, in particular, contains wonderful insights on the physiology of combat that bear further study and incorporation within the discipline. However, Grossman’s current “killology” literature contains some serious problems, and there are some worrying flaws in the theories that are being preached as truth to the men and women of the Canadian Forces. Although much of Grossman’s work is credible, his proposed theories on the inability of human beings to kill one another, while optimistic, are not sufficiently reinforced to warrant uncritical acceptance. A reassessment of the value that this material holds for the Canadian military is necessary.

The evidence seems to indicate that, contrary to Grossman’s ideas, killing is a natural, if difficult, part of human behaviour, and that killology’s belief that soldiers and the population at large are only being able to kill as part of programmed behaviour (or as a symptom of mental illness) hinders our understanding of the actualities of warfare. A flawed understanding of how and why soldiers can kill is no more helpful to the study of military history than it is to practitioners of the military profession. More research in this area is required, and On Killing and On Combat should be treated as the starting points, rather than the culmination, of this process.

Man isn’t alone in the killing game:

It is conceivable that restraint and posturing in intra-specific combat developed as adaptations in some species, since, in nature, deadly combat would likely leave the victor almost as mauled as the loser. A species that could gradually adapt toward non-lethal intra-specific violence might possess a reproductive advantage. At the same time, however, deadly aggression can also be viewed from an evolutionary perspective as an adaptation. Despite Grossman’s claims to the contrary, animals do kill within their own species. Mankind’s closest genetic relative in the animal kingdom is the common chimpanzee, with whom we share some 98.4 percent of our DNA. There have been many documented cases of chimpanzees killing each other, most famously in Dr. Jane Goodall’s observation of the extermination of one chimpanzee band by another between 1974 and 1977. Pulitzer Prize-winning writer and scientist Jared Diamond claims, “…[that] of all our human hallmarks … the one that has been derived most straightforwardly from animal precursors is genocide. Common chimps already carried out planned killings, extermination of neighboring bands, wars of territorial conquest, and abduction of nubile young females.” Diamond takes this point further, saying, “…[that] if chimps were given spears and some instruction in their use, their killing would undoubtedly begin to approach ours in efficiency.” Aside from the primates, wolves and other wild dogs engage in very deadly intra-specific fighting, and, beyond the humans that hunt them, they are generally their own greatest source of mortality. The common pavement ant is notoriously aggressive, engaging in pitched battles involving masses of workers. Lions also on occasion kill other lions, and there are reports of the killing and cannibalization of cubs after one of their protector males has died and their territory was invaded by other prides. Species do exist that have adapted, if not for constant murderous behaviour, then at least for the potential for deadly intra-specific competition; others have evolved toward more non-lethal violence. Chimpanzees kill one another, but gorillas do not appear to do so. More research into these phenomena is required, but this evidence does not suggest a universal “resistance to killing” biological imperative at work. Within some species, the ability and willingness to kill its own kind, and to develop a reputation for doing so, can be seen as a beneficial adaptation.14 Biologist Konrad Lorenz believed that mankind in particular had never developed non-lethal intra-specific behaviour or structural elements. While Grossman claims otherwise, there is no evidence of a “natural” resistance to killing governing intra-specific behaviour in the animal kingdom.

On Grossman’s use of S.L.A. Marshall’s earlier work:

Grossman draws most of the evidence for his theories on killing from military history, specifically, from the controversial writings of S.L.A. Marshall, a journalist with the US Army’s Historical Section during the Second World War. Marshall developed an innovative post-combat interview technique wherein he would speak to a unit of soldiers fresh out of combat, and, together, they would attempt to reconstruct an action. In terms of historical methodology this was a good idea. However, the claims that Marshall made, supposedly based upon his interview data, proved to be controversial. He claimed that only 15 to 25 percent of even the best-trained soldiers would ever fire their weapons in combat. As Marshall wrote in his book on the subject, Men against Fire, “… 75 per cent will not fire or will not persist in firing at the enemy and his works. These men may face danger but they will not fight.” Marshall’s conclusion was that the average, healthy individual possessed an unconscious “…inner unrealized resistance toward killing a fellow man,” although with Marshall there was no talk of evolutionary biology and more reference to socialization. He claimed that these statistics were a universal truth of human combat, fully backed up by his painstaking research and interviews.

But when did Marshall compile his statistics?

Here, Marshall becomes extremely problematic as a source. Historians and researchers since the 1980s have been consistently demonstrating that Marshall did not have the evidence to back up his claims. Roger Spiller, among the first historians to publicly criticize Marshall, claimed that his ratio of fire numbers were “…an invention,” and that “Marshall had no use for polite equivocations of scholarly discourse. His way of proving doubtful propositions was to state them forcefully. Righteousness was always more important for Marshall than evidence.” Other historians discovered that none of Marshall’s aides and assistants could ever remember Marshall asking the troops questions during the group interviews that had anything to do with whether they had fired their weapons. In the surviving field notebooks used by Marshall during his interviews, historians have found no signs of the statistical compilations that would have been necessary to deduce a ratio as precise as that found in Men Against Fire. Such a precise, surprising number as the 15 to 25 percent ratio should have required a great amount of hard work and data-gathering to arrive at, but there is no evidence that Marshall carried out the statistical legwork his claims imply. The only interview notes actually located were found in an archive of a Maryland National Guard division, wherein soldiers testified to having used their weapons in action. There was no mention of the ratio of fire.

Nearly a decade ago on the old site, I linked to a debunking of Marshall’s work and said: “I had to assume, as Marshall’s work was constantly being praised by (mostly) American writers, that even if it wasn’t true for Canadian, British, German, Russian, or even French soldiers, it must be true of American soldiers. Which dovetailed nicely with my early anti-American feelings. So, a big-name American general says that Yankee soldiers are too timid to fire their weapons in combat 75% of the time? No wonder they’re losing in Vietnam.”

Speaking directly to the Canadian Army’s post-battle investigations in the Second World War:

The issue of Marshall’s ratio of fire was one that I have always found to be very interesting, and when I decided to pursue graduate studies in history, I began researching the subject to see what corroborating evidence might exist in the primary source documentation. In mid-2007, I began examining a series of battle experience questionnaires filled out by Canadian infantry officers during the Second World War, addressing as they did a wide array of tactical questions, and giving the soldiers the opportunity to provide feedback and personal comments with respect to combat. Several hundred questionnaires were filled out by Canadians from rifle companies in 1944 and 1945 shortly after they had returned from combat, giving them the same immediacy attributed to Marshall’s group interviews. Given the similar timeframe to Marshall, as well as the similar content, I believe they are at least as credible a source as Men Against Fire, and likely more so, since the original questionnaires can still be found and verified at the Library and Archives Canada (LAC) in Ottawa. These battle experience questionnaires are quite candid, and they explore the tactical realities facing Allied soldiers in the Second World War, both in the Mediterranean theatre and in northwest Europe. I perused over 150 of the infantry surveys stored at LAC over the course of several months, compiling statistics from the formal survey questions and transcribing all the informal personal comments that had been attached. The evidence I collected became the basis for my Master’s thesis, which, as this article goes to press, is being revised as a manuscript.

There is a wealth of varied information contained in these questionnaires, but what they can tell us about Marshall’s ratio of fire is pivotal. Not a single one of the questionnaires – filled out by infantry officers who fought at close quarters and commanded rifle companies, platoons, and sections in combat – mentions anything about soldiers not firing their weapons. Indeed, the exact opposite appeared to be the major problem – that is, Canadian troops firing too much, wasting ammunition, and giving away their positions. Most officers, however, were generally satisfied with the rate of small-arms fire, and they regarded it as being very effective in battle, particularly for defeating the inevitable German counterattacks that followed every offensive action. A failure on the part of some of their troops to actively participate in battle was only highlighted by a few respondents during discussions of combat fatigue and ‘green’ replacement soldiers, and even those cases constituted a small minority. If over 75 percent of the riflemen under their command would not fight, as Marshall and Grossman claim, then the officers filling out the questionnaires would have noticed. Given their candid responses and genuine desire to help the Canadian Army train and fight better – the stated purpose of the questionnaires was to provide feedback with respect to combat training and experience while the war was still going on – it is extremely implausible that they would have overlooked, concealed, or covered up such alarmingly relevant information.

The questionnaires demonstrate that infantry combat is too complex, fluid, and terrifying an experience to be reduced to simple numbers. Today’s hero could easily be tomorrow’s coward (a point Marshall tried to make), and soldiers could not easily be reduced to the labels of killer/non-killer, or shooter/non-shooter.

A parallel study to Marshall’s interviews, then, fully documented and straight from the subjects themselves with no intermediary, presents data that is in direct contradiction to that of Marshall. The questionnaire respondents were exclusively Canadian, of course, and they cover a completely different set of subjects than Marshall’s interviews. They also apply only to the Canadian experience. However, Marshall strongly implied that his 15 to 25 percent ratio of fire was a universal condition of modern warfare, and Grossman has been very explicit in his championing of the universality of this phenomenon as a part of human nature. The evidence from the Canadian battle experience questionnaires indicates that non-participation in combat by riflemen was not a problem in the Canadian Army between 1943 and 1945; that infantry fire was usually quite effective; and that if there was a problem with the firing it was always due to too much fire rather than too little. Supposing Marshall was correct with respect to his claims, and there were problems with non-participation in the US Army, then either the Canadian Army was, by Grossman’s reckoning, many times more effective a fighting force (of which there is no evidence) or else claiming the universality of Marshall’s findings is factually incorrect. While it might be going too far to call S.L.A. Marshall a liar, he appears to have simply been wrong in his claims about the ratio of fire.