In Humankind: A Hopeful History by Rutger Bregman, Rutger Bregman claims that humans aren’t violent by nature. A key piece of evidence is that most soldiers never fire a shot in warfare.

I’ve seen other people challenge this claim. I decided to ask OpenAI’s DeepResearch the question:

As I was reading Humankind, a Hopeful History by Ruger Bregman, I saw the claim that human violence isn’t as essential to our nature as many claim. He gives a piece of evidence: many soldiers never fire their weapon. He gives historical examples, and also addresses the fact that modern soldiers are claimed to engage much more frequently by pointing out that warfare is now rarely personal and the killing is usually done remotely.

I’m curious to know the state of the overall research on the idea that a significant proportion of people in warfare choose not to engage in violent, both the historical claims and also the modern claims. Please give me examples and counter examples, the most common studies and their rebuttals.

The Reluctance to Kill in War: A Survey of Research

Introduction

It is a paradox of warfare that many soldiers on the battlefield choose not to kill, even when their own lives are at risk. Across different eras and cultures, a significant proportion of combatants have refrained from firing their weapons or have intentionally aimed to miss the enemy. This phenomenon – sometimes called the “non-firer” or “ratio of fire” problem – has been documented in historical records and sparked extensive research in psychology, military history, and anthropology. Scholars have debated whether an innate human aversion to killing underlies this reluctance (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Hope on the Battlefield | Greater Good), or if circumstances and conditioning determine when people become violent. This report examines key studies of soldiers not engaging in violence, from early observations in the 19th century to modern analyses, and contrasts interpretations that view humans as fundamentally peace-seeking with those that argue violence emerges from innate or situational factors.

Historical Evidence of Soldiers Not Killing

Early and 19th-Century Observations: Long before modern research, military observers noted that in battle only a minority of soldiers actually try to kill. French army officer Col. Ardant du Picq in the 1860s circulated questionnaires to veterans and found many soldiers fired harmlessly into the air rather than at enemy targets (Hope on the Battlefield | Greater Good). One French officer admitted “a good many soldiers fired into the air at long distances,” and another observed some men fired without aiming, seemingly trying to “stun themselves” with noise rather than shoot the enemy (Hope on the Battlefield | Greater Good). These anecdotes suggested that perhaps only ~25% of soldiers aimed to kill, a figure du Picq believed could be improved by unit cohesion and discipline. Similarly, in earlier musket warfare, there were curious signs of non-engagement. After the Battle of Gettysburg (1863) in the American Civil War, recovery teams found tens of thousands of muskets that had been loaded multiple times without being fired. Of ~27,000 collected rifles, about 24,000 were still loaded, and roughly half contained multiple loads – one was packed with 23 rounds in the barrel (Why the guns at Gettysburg were found loaded | The Vintage News) (Humankind: A Hopeful History - Wikipedia). Historians later concluded that many soldiers kept reloading as a “perfect excuse not to shoot”, pretending to fire amidst the chaos without actually harming the enemy (Why the guns at Gettysburg were found loaded | The Vintage News) (Humankind: A Hopeful History - Wikipedia). While some of these unfired muskets may have resulted from misfires or confusion under stress, the sheer scale of over-loaded weapons implies that a large number of Civil War infantry never pulled the trigger in combat.

World War I – “Live and Let Live”: In the trench warfare of WWI, there were striking cases of deliberate minimal violence. Aside from famous events like the Christmas Truce of 1914, where British and German soldiers openly fraternized and ceased fighting, soldiers often developed an unspoken “live and let live” system in the trenches (Conspiring with the Enemy and Cooperating in Warfare - Ideas | Institute for Advanced Study) (Conspiring with the Enemy and Cooperating in Warfare - Ideas | Institute for Advanced Study). Historical analyses by Tony Ashworth found that on many trench sectors both sides would avoid aiming to kill, firing routine shell bursts at predictable times or above head level so the other side could take cover (Conspiring with the Enemy and Cooperating in Warfare - Ideas | Institute for Advanced Study) (Conspiring with the Enemy and Cooperating in Warfare - Ideas | Institute for Advanced Study). Diaries and letters described “quiet fronts” where men moved freely and even lit cooking fires without drawing enemy fire (Conspiring with the Enemy and Cooperating in Warfare - Ideas | Institute for Advanced Study). In other words, mutual tacit agreements sometimes replaced bloodlust: survival and soldierly solidarity led opponents to cooperate by not killing. These WWI practices underscore that even in a war known for carnage, there were numerous instances in which soldiers on both sides chose restraint over violence.

World War II – S.L.A. Marshall’s Findings: The most famous—and controversial—evidence for non-engagement comes from Brig. Gen. S.L.A. Marshall, a U.S. Army combat historian in WWII. After interviewing hundreds of American infantrymen shortly after battles, Marshall concluded in his influential book Men Against Fire (1947) that on average only 15–25% of U.S. riflemen fired their weapons at the enemy (). In other words, perhaps 75–85% of soldiers did not attempt to shoot at enemy soldiers, even under fire. Marshall described soldiers in combat as “spectators” who resisted pulling the trigger due to an innate revulsion against killing (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (). He asserted this low “ratio of fire” was not due to cowardice – those who didn’t fire often still exposed themselves to danger to help wounded comrades or carry ammo (Hope on the Battlefield | Greater Good) – but rather a subconscious “fear of aggression” deeply ingrained in the average man’s psyche (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Marshall boldly extrapolated that this reluctance to kill was likely “ubiquitous throughout history”, only previously unnoticed because earlier wars lacked systematic data collection (). His WWII findings, if true, confirmed the pattern glimpsed in earlier eras: most soldiers, left to their own instincts, would rather not take a life.

S.L.A. Marshall’s Influence and Debates

Marshall’s startling statistics had an immediate and lasting impact. Military leaders took note of the implication that only a fraction of their troops were fighting. As a result, post-WWII training was overhauled to overcome this reluctance (). Marshall is often credited with prompting the U.S. Army to introduce conditioning techniques – for example, replacing bullseye targets with human-shaped silhouettes in marksmanship training – to reflexively engage soldiers to fire in combat (). By the time of the Vietnam War, this retraining seemed to have dramatically raised firing rates. Marshall himself claimed that in Korea (1950–53) and especially Vietnam, the problem had been largely solved, with “close to 100% of American infantrymen” in firefights actively shooting at the enemy (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Indeed, independent research supports a major change by Vietnam: A 1987 survey of 1st Cavalry Division Vietnam veterans found they estimated about 84% of riflemen and 90% of machine-gunners in their units fired their weapons in combat (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). This is essentially the inverse of the WWII ratio – roughly 4 out of 5 soldiers engaged the enemy in Vietnam, versus only 1 in 5 in WWII. Marshall’s supporters saw this as vindication that better training and conditioning (from drill field to boot camp) can override soldiers’ innate hesitance and make them more willing to fire (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War).

However, Marshall’s work has also faced intense scrutiny and criticism. Starting in the 1980s, historians probed his methods and found reason to doubt his exact numbers. No official records of Marshall’s platoon interviews were ever produced, and some colleagues alleged that he never systematically counted who fired and who didn’t (). Critics like Roger J. Spiller and historian Robert Engen argue that Marshall’s data was at best “desultory” and at worst essentially anecdotal or fabricated (). For example, Canada’s military archives from the same WWII campaigns (Normandy, 1944) include detailed post-combat studies by the British Weapons Technical Staff on infantry weapon usage – those reports found no sign of widespread refusal to fire among Canadian/British units (). If 80% of riflemen had hung back in those battles, the analysts likely would have noted it, but they did not (). This suggests Marshall’s universal law of non-firing might not apply equally to all armies or situations () (). Some scholars also point out that Marshall may have interpreted any soldier not firing at a given moment as “refusing” to fire, when in reality many factors (confusion, lack of a target, weapon jams) could explain not shooting. In short, Marshall’s 15–20% figure remains debated: it was hugely influential, but later researchers have struggled to verify it as a hard statistic () ().

Notwithstanding these methodological doubts, Marshall’s central premise – that humans have an inherent resistance to killing – has been supported by other evidence and has influenced a generation of military psychologists. Ret. Lt. Col. Dave Grossman, in his book On Killing (1995), expanded on Marshall’s idea of an “inner resistance” and dubbed the field “killology.” Grossman compiled historical data and interviews, concluding that “there is, within most people, an intense resistance to killing others”, so strong that many soldiers will endure great risk or disobey orders rather than pull the trigger (Hope on the Battlefield | Greater Good) (Hope on the Battlefield | Greater Good). He notes that those who didn’t fire in WWII often still stood their ground – they were not simply panicking or fleeing – implying a moral or psychological restraint rather than lack of courage (Hope on the Battlefield | Greater Good). Grossman and others also cite rising post-traumatic stress disorder (PTSD) rates as modern armies overcome natural aversion: forcing soldiers to kill more efficiently carries a heavy psychological cost later (Hope on the Battlefield | Greater Good). In Grossman’s view, Marshall identified a fundamental human trait, and the subsequent improvements in firing rates (Vietnam and beyond) are a result of militaries systematically training soldiers to override that trait – through desensitization, operant conditioning, and group pressure (Hope on the Battlefield | Greater Good) (Hope on the Battlefield | Greater Good). This interpretation remains prominent in military literature, though skeptics caution that Marshall’s precise statistics might not be universally accurate () ().

Modern Data and Counterexamples of High Violence

While many accounts affirm widespread non-killing by soldiers, there are also cases and studies showing that under certain conditions, violence becomes the norm rather than the exception. The Vietnam veteran survey mentioned above is one example: by the 1960s, the U.S. had so refined its training (e.g. realistic combat simulations, reward for marksmanship, instinctive firing drills) that the vast majority of soldiers did fire at the enemy (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Those veterans still recalled a minority (~16%) who didn’t fire, but this was a far smaller fraction than in WWII. Their testimonies also illuminate why some still abstained: many non-firers were in roles like medics, radio operators, or leaders whose primary duties weren’t shooting (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). In other cases, soldiers held fire due to tactical judgment (for instance, not springing an ambush if hugely outnumbered, to avoid giving away position) rather than personal inhibition (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Fear was a factor too – about 80% of Vietnam vets surveyed said fear sometimes froze a man momentarily so he couldn’t fire (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Importantly, they observed this fear was usually fleeting: a man might fail to fire at the very start of a firefight, overwhelmed by shock, but minutes later the same soldier would likely engage once he collected himself (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). In other words, situational factors (like being a newcomer in your first battle, or being caught by surprise) explained many instances of non-firing in Vietnam, rather than an enduring unwillingness to fight (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War).

Furthermore, history provides grim counterexamples where violence was rampant, suggesting human behavior in war is highly context-dependent. On fronts characterized by intense hatred or desperation, soldiers have shown far less reluctance to kill. For instance, on the Eastern Front of WWII and in the Pacific War, both sides often demonized the enemy and engaged in close-quarters combat that yielded very high casualty rates. Anecdotal evidence indicates that Japanese infantry, indoctrinated with the bushidō ethic, and Soviet troops, driven by survival and coercion, did fire and kill at much higher rates – albeit backed by harsh discipline (e.g. Soviet blocking units) to enforce fighting. In such environments, any innate hesitancy was overwhelmed by fear of leadership, propaganda, and a kill-or-be-killed reality. Social psychologists note that when soldiers strongly dehumanize the enemy, their inhibitions can evaporate. Experiments have shown that describing a target in dehumanizing terms leads participants to deliver greater shocks or aggression in lab settings (Disinhibition of aggression through diffusion of responsibility and …) ([PDF] Moral Disengagement In The Perpetration Of Inhumanities - CiteSeerX). In war, militaries frequently encourage dehumanizing the foe (“hate the enemy”) precisely to increase aggression. Tragically, this can enable atrocities: for example, Reserve Police Battalion 101, a German unit of ordinary middle-aged men, became willing executioners of civilians in WWII after peer pressure, gradual desensitization, and orders from authority – even though these men initially showed revulsion, most eventually participated in mass killings. Their story, documented by historian Christopher Browning, illustrates that average people can become prolific killers under strong situational pressures (authority commands, group norms, no punishment for refusal), despite no prior inclination to violence.

Another modern counterpoint is the all-volunteer professional forces in many countries today. Some argue volunteer soldiers might be inherently more disposed to fight than draftees. However, research still finds human reluctance even in volunteer armies – for example, U.S. Special Forces in Afghanistan noted Afghan partner militia would sometimes fire indiscriminately over the enemy or hold fire altogether until leadership compelled them, indicating the phenomenon is not limited to conscripts or any one culture. Meanwhile, drone operators and artillery crews (who wage war at a distance) usually have no trouble “firing” when ordered, since the emotional distance and lack of visible bloodshed bypass the innate empathy that might restrain an infantryman looking an enemy in the eyes. This highlights a key psychological principle: the more personal and up-close the killing, the harder it is for most humans to do. Conversely, distance, technology, and diffusion of responsibility (e.g. operating a crew-served weapon as just one cog in the machine) can raise participation in violence. Modern military technology, from long-range missiles to remote drones, essentially leverages this aspect – making lethal action feel less personal and therefore easier on the human psyche.

Psychological Explanations for Reluctance to Kill

Why do so many individuals, thrown into life-or-death combat, fail to fire at the enemy? Researchers have proposed a range of psychological explanations:

• Innate Moral Inhibition: Marshall and subsequent psychologists argue that humans have a built-in aversion to killing members of their own species (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Hope on the Battlefield | Greater Good). From a young age we learn that harming others is profoundly wrong; this “Thou Shalt Not Kill” conditioning runs deep (“practically with his mother’s milk,” Marshall wrote (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War)). When a soldier tries to fire at a person, an unconscious moral grammar may restrain the trigger finger. Soldiers describe feeling physically unable to shoot directly at an enemy in their sights, as if some inner voice or reflex balks at lethal aggression. This aligns with the concept of empathy – it is hard for a typical person to kill someone who, at that moment, poses no direct personal threat (especially if the enemy is not personally hated, but an anonymous figure in a uniform).

• Fear and Stress Responses: In combat, the body’s acute stress response (fight, flight or freeze) can cause a “freeze-up” under fire. Many non-firers likely experienced overwhelming fear that momentarily incapacitated them (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Rather than deliberate pacifism, they were simply paralyzed by combat shock – heart racing, senses overwhelmed by noise and chaos. Not firing could be the result of this temporary freezing. Notably, veterans say such fear-based non-firing is often transient; once the initial shock passes or the soldier is rallied by comrades or leaders, they may start shooting (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Nonetheless, in the critical first moments of an engagement, this hesitation means some do not return fire. Fear can also manifest as hyper-focus on self-preservation (ducking, finding cover) to the exclusion of offensive action. Psychological resilience and experience play a role – green troops are far more likely to freeze and fail to fire in their first combat, whereas battle-hardened troops are able to overcome the shock and act.

• Diffusion of Responsibility & Social Proof: In a firefight with dozens of fellow soldiers, an individual might think “others will shoot, so I don’t have to.” Especially if leadership is not directly ordering each man to fire, a soldier can opt out without immediate consequence, hidden by the noise and confusion. As long as some guns are firing, an enemy is engaged, one’s personal contribution might feel less critical. This diffusion of responsibility can reduce the guilt of inaction (“someone else will do it”). Likewise, humans are sensitive to social cues: if those around you aren’t shooting, you may also hold fire, consciously or not. (Marshall anecdotally noted that if an officer or respected comrade was watching, soldiers were more likely to fire (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War), implying that solitude or lack of oversight enabled non-firing.) In many historical cases, non-firers were not cowards running away – they stayed with their unit, perhaps loading weapons or taking cover, but abstained from killing. As long as the unit as a whole was fighting, an individual could appear busy – loading, tending equipment – while never actually firing a shot (Why the guns at Gettysburg were found loaded | The Vintage News).

• “Posturing” and Threatening Without Killing: Some psychologists liken battlefield behavior to animal behavior – much of combat is posturing or bluff. Grossman notes that when faced with living opponents, a “significant majority” of soldiers default to a posture mode, firing over heads or making noise rather than aiming to kill (Hope on the Battlefield | Greater Good). In essence, they try to intimidate or scare off the enemy with firing sounds, hoping the enemy will take cover or retreat, rather than consciously trying to shoot them dead. This behavior might satisfy one’s duty (“I’m firing”) while still avoiding the personal guilt of killing. It’s a compromise between total refusal and lethal intent.

• Personal Identification with the Enemy: Especially in civil wars or conflicts where combatants share a cultural or linguistic background, soldiers may feel kinship or pity for their adversaries. Even in international wars, soldiers sometimes recognize the common humanity of the man in their gunsight. This can create a mental barrier to pulling the trigger. Famous accounts from WWI describe soldiers on opposite sides shouting insults rather than shooting, or intentionally aiming high, because they sensed the enemy were men just like them trying to survive (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia). That basic empathy can be hard to extinguish, unless overridden by indoctrination or hatred.

• Leadership and Rules of Engagement: Soldiers are trained to follow orders – many will fire when explicitly commanded to by an authority figure or when seeing others fire (since not doing so might be punished or shamed). But in the absence of clear orders, some default to caution. If officers encourage restraint (to avoid giving away position or wasting ammo), troops may take it to heart and hold fire longer than necessary. In contrast, strong, present leadership tends to increase firing rates by giving direct orders or setting an example. The presence of comrades also matters: a soldier is more likely to shoot if it’s necessary to protect buddies in immediate danger (self-defense and defense of others can overcome hesitation). Many who had trouble shooting at distant enemies had no trouble in close combat when their unit was directly assaulted – survival instincts and loyalty can trump reluctance in those moments.

• Moral Injury and Guilt: A growing body of research on moral injury suggests soldiers intuitively fear the emotional aftermath of killing. Even before pulling the trigger, a part of the psyche might anticipate guilt, sorrow, or spiritual anguish that could follow killing another human. This anticipation can act as a preventive brake. Interviews with soldiers who did kill often reveal tormenting memories and remorse. Those still in the moment may avoid firing partly to avoid crossing that moral Rubicon. In some cases, veterans confessed they could have shot an enemy soldier but chose not to, and while they risked their own side, they live with relief rather than regret. Such complex moral calculus shows that battlefield behavior isn’t purely fight-or-flight – conscience plays a role even amid combat.

Human Nature: Peaceful or Warlike? (Bregman vs. Others)

The question of why many soldiers don’t kill ties into a broader debate about human nature and violence. Rutger Bregman, in Humankind: A Hopeful History (2019), interprets the reluctance to fight as evidence that violence is not natural to humans. He aligns with a Rousseau-like view that people are fundamentally decent and do not want to harm each other absent coercion. Bregman highlights Marshall’s WWII discovery that “the vast majority of even professional soldiers will refuse to fire their firearms” at enemies (Humankind: A Hopeful History - Wikipedia). He also points to historical data like the loaded muskets at Gettysburg (90% unfired) as proof that humans, even in war, often avoid killing if they can (Humankind: A Hopeful History - Wikipedia). In Bregman’s narrative, these findings undermine the notion of an innate “killer instinct.” Instead, they suggest our default is cooperation and restraint, and war requires special conditioning or circumstances to make people overcome their natural aversion to violence (Humankind: A Hopeful History - Wikipedia) (Hope on the Battlefield | Greater Good). He further cites examples from anthropology: some indigenous cultures (like the !Kung bushmen studied by Elizabeth Marshall Thomas) traditionally fought battles that were more ritualistic shouting matches than lethal fights (Humankind: A Hopeful History - Wikipedia). Such cases imply that warfare as all-out slaughter is not a human universal, but often a result of social and organizational pressure. Bregman and similar thinkers (e.g. anthropologist Ashley Montagu or psychologist Alfie Kohn) argue that humans are “wired for empathy” and that brutality is a breakdown of our true nature, usually triggered by leadership, ideology, or extreme fear.

On the other side of the debate, many scholars argue that humans do have innate aggressive drives or at least a natural capacity for violence under certain conditions. Early ethologists like Konrad Lorenz (in On Aggression, 1966) posited that humans share with animals an instinctual aggression that can be triggered by stimuli, though in humans it’s modulated by culture. Evolutionary psychologists and sociobiologists point out that throughout prehistoric and recorded history, warfare and violent competition were common, which likely selected for psychological mechanisms favoring aggression toward out-groups. Anthropologist Napoleon Chagnon’s famous study of the Yanomamö tribe in the Amazon (1960s) described them as living in a “ferocious” state of chronic warfare, with a significant portion of males dying in battle and successful warriors allegedly gaining more wives and offspring (Humankind: A Hopeful History - Wikipedia). This was interpreted as evidence that violence had evolutionary rewards (though aspects of Chagnon’s data were later questioned (Humankind: A Hopeful History - Wikipedia)). Additionally, cognitive experiments like Stanley Milgram’s obedience study (1963) demonstrated that ordinary people were willing to inflict what they thought were lethal electric shocks on a stranger when an authority figure insisted – about 65% went to the maximum voltage. This suggests that while people may not want to harm others, our psychology can be easily subverted by authority or situational pressure into committing violence. Similarly, the controversial Stanford Prison Experiment (1971) seemed to show that people adopted cruel behaviors in a prison-guard role, implying context can rapidly erode empathy. Although that experiment’s methods are now criticized, its takeaway aligned with the idea that situational factors (power, group identity, dehumanization) can awaken latent cruelty.

Modern scholars like psychologist Steven Pinker take a nuanced position: humans have inner demons and better angels. Pinker acknowledges evolutionary “demons” – tendencies toward dominance, revenge, or ideology-fueled violence – but also empathy, self-control, and reason as “angels” that check our violent impulses. In The Better Angels of Our Nature (2011), Pinker presents data that in non-state societies, rates of violent death were extremely high (often 10–20% of males died in warfare), far above 20th-century levels (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia). This implies that in some environments humans readily engage in lethal violence, perhaps as a rational strategy over resources or due to lack of strong authority to stop cycles of revenge. Pinker’s view is that violence is part of human potential, but one that societies have gradually learned to curb through state authority, trade, cosmopolitan values, and education – hence overall violence has declined over centuries. If Pinker’s analysis is correct, it doesn’t contradict the soldier reluctance phenomenon; rather, it suggests that context is key. Humans are neither born angels nor demons; we have propensities for compassion and for aggression. On a personal, immediate level, compassion often prevails (a soldier sees a living person in his sights and can’t shoot). Yet given certain triggers – ideology, fear for one’s own group, hatred of an out-group, orders from a commander – those latent aggressive circuits can activate, sometimes with horrific results. The instinct not to kill might be strong, but it is not unbreakable.

Sociological perspectives add that group dynamics and culture determine how easily those violent triggers are pulled. Armies have long known that unit cohesion and peer expectations can drive men to kill enemies they might otherwise hesitate to harm. Conversely, if a culture strongly disapproves of killing (e.g. many religious teachings), even soldiers may aim to wound rather than kill, or engage in war in non-lethal ways. Anthropologist Margaret Mead, in a 1940 essay, famously argued that warfare is a human invention, not a biological necessity – meaning if a society doesn’t culturally “invent” the idea of war, its members won’t organize killing on a large scale. This optimistic view aligns with Bregman’s thesis that violence is not inevitable. Yet others note that nearly all human societies did invent warfare independently, implying some underlying readiness across humanity to resort to group violence under pressure.

In sum, the academic discourse sees a spectrum of interpretations: On one end, the “Humans are peaceful” camp highlights the reluctance of soldiers to kill and the need for powerful inducements to make ordinary people commit violence (Hope on the Battlefield | Greater Good) (Hope on the Battlefield | Greater Good). On the other end, the “Humans can be violent” camp stresses that history and evolution have endowed us with aggressive capacities that emerge readily when normal restraints are removed. Both views agree that most individuals are not eager to kill in face-to-face situations – a point demonstrated by the widespread non-firing phenomenon – but they differ on whether this reflects an inherent goodness or simply the right circumstances not yet forcing their hand.

Conclusion

The finding that many soldiers in war choose not to fire their weapons or deliberately avoid killing is one of the most intriguing insights into combat behavior. It appears consistently in historical anecdotes (from muzzle-loading muskets to modern rifles) and is supported by psychological research: humans have a strong aversion to killing one another, an instinct that armies must override to wage war effectively (Hope on the Battlefield | Greater Good) (Hope on the Battlefield | Greater Good). This aversion is rooted in empathy, moral conditioning, and perhaps evolutionary advantages of cooperation. However, it is equally clear that given the right combination of situational triggers – intense fear, authoritarian command, hatred, or simply rigorous training that conditions reflexive shooting – humans are capable of lethal violence on a vast scale. The academic literature reflects this tension. On one side, optimists like Bregman see the reluctance to kill as evidence that humankind’s nature is fundamentally benign, with violence as a maladaptive aberration. On the other, realists and evolutionary thinkers contend that while we may not enjoy killing, we carry psychological mechanisms that can be rapidly engaged to overcome our reluctance when survival or group loyalty demands it.

For military psychology, the practical takeaway has been to recognize the importance of training, leadership, and group cohesion in determining soldiers’ behavior. Modern armies devote great effort to simulate combat and normalize the act of shooting at human targets, essentially to suppress the innate hesitation documented in WWII. At the same time, the increase in PTSD and moral injury cases in recent conflicts is a stark reminder that even if soldiers can be conditioned to kill, their fundamental nature has not changed – the psychological cost of taking life remains high (Hope on the Battlefield | Greater Good). Anthropological and sociological insights likewise remind us that war is not just a matter of individual psychology but of culture and circumstance: how a society frames the act of killing (heroic, tragic, necessary, evil) will influence how its soldiers perform in battle.

In conclusion, the fact that so many combatants across history failed to fire or aimed to miss suggests that violence does not come easily to the human animal. It requires overcoming deep psychological barriers, whether through drill, desperation, or dehumanization of the enemy. Understanding this duality – our reluctance to kill and our ability to do so under pressure – is crucial for both military leadership and for humanity’s broader hope of mitigating war. If violence truly “is not in our nature” to initiate, as some argue, then nurturing our empathetic instincts might be key to peace. But if the capacity for violence lies dormant in all of us, then preventing war may depend on structuring society and situations such that those violent impulses are never brutally activated. The truth likely lies in between: human nature contains multitudes, and war has always been a struggle to unleash certain parts of it while restraining others.

Summary of Key Studies and Findings

Study/Source	Context & Data	Key Findings	Interpretation / Critique
Col. Ardant du Picq (1860s)	Survey of French officers (mid-19th C.) ([Hope on the Battlefield	Greater Good](https://greatergood.berkeley.edu/article/item/hope_on_the_battlefield#:~:text=When%2019th,%E2%80%9D))	Many soldiers fired high or without aiming in battle. One officer noted “a good many…fired into the air,” indicating deliberate non-lethal fire ([Hope on the Battlefield
Gettysburg Musket Analysis (1863)	Post-battle recovery of rifles, American Civil War ([Why the guns at Gettysburg were found loaded	The Vintage News](https://www.thevintagenews.com/2016/08/30/guns-gettysburg-found-loaded/#:~:text=The%20numbers%20we%20have%20today,never%20fired%20a%20single%20shot)) (Humankind: A Hopeful History - Wikipedia)	Of ~27,000 rifles collected, ~24,000 (≈90%) were loaded (had not been fired); ~12,000 had multiple loads, one with 23 bullets in the barrel ([Why the guns at Gettysburg were found loaded
“Live and Let Live” in WWI (1914–18)	Trench warfare on Western Front (documented by Tony Ashworth, 1980) ([Conspiring with the Enemy and Cooperating in Warfare - Ideas	Institute for Advanced Study](https://www.ias.edu/ideas/2014/chiu-war#:~:text=In%20addition%20to%20ad%20hoc,were%20explicit%20agreements%20between%20fraternizing)) ([Conspiring with the Enemy and Cooperating in Warfare - Ideas	Institute for Advanced Study](https://www.ias.edu/ideas/2014/chiu-war#:~:text=There%20were%20numerous%20reports%20of,and%20had%20pianos%20and%20books))
S.L.A. Marshall (WWII)	U.S. Army historian’s interviews post-combat (1943–45) ()	Claimed only 15–20% of American riflemen fired at the enemy in WWII battles (). The rest did not fire at an exposed enemy, even to save their lives. Non-firers still assisted in non-shooting tasks ([Hope on the Battlefield	Greater Good](https://greatergood.berkeley.edu/article/item/hope_on_the_battlefield#:~:text=German%20or%20Japanese%20troops,repeated%20waves%20of%20banzai%20charges)).
British Army Weapon Surveys (WWII)	Weapons Technical Staff studies of 100+ companies (1944–45) () ()	Detailed reports on infantry weapon usage by UK/Canadian units found no mention of deliberate non-firing (). Troops held fire at times for tactical reasons (e.g. to preserve surprise) () (), but no evidence of 80% refusing combat.	Contrary evidence to Marshall in similar battles. Suggests national or situational differences – Canadian/British troops may have engaged more, or analysts didn’t detect passive non-firers. Indicates Marshall’s ratio might not be a universal constant. Often cited by Marshall’s critics to question his conclusions () ().
U.S. Training Changes & Korea/Vietnam	U.S. Army (1950s–60s) – new training methods; Marshall’s later observations (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War)	By Korean War and Vietnam, firing rates reportedly rose to 55%, then ~90%. Marshall claimed close to 100% of U.S. infantry fired at enemies in Vietnam firefights (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Field surveys of Vietnam vets (1st Cav Div) found ~84% of riflemen and 90% of crew-weapon gunners fired in combat (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War).	Shows conditioning and drills were effective in overcoming reluctance. The near-universal engagement in Vietnam is a counterexample to the WWII pattern (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). However, ~15% still did not fire, often due to role (medic, leader) or initial fear (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War). Suggests reluctance can be reduced but not eliminated by training. Marshall’s Vietnam claims are less contested but lacked rigorous data; the 1987 vet survey provides empirical support (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War) (Men Against Fire: How Many Soldiers Actually Fired Their Weapons at the Enemy During the Vietnam War).
Brig. Gen. S.L.A. Marshall’s Critics	Scholarly analyses (1980s–2000s) by Spiller, Engen, etc. () ()	Found no archival evidence of Marshall’s systematic counts; witnesses said he did not actually tally shots fired (). Canadian records and other wars’ data don’t fully support a fixed “85% non-firing” rate () ().	Conclude that Marshall’s ratio-of-fire was likely overstated or at least not universal (). Some call it a “ Marshall Paradigm” rather than proven fact (). Nonetheless, even critics accept that some non-trivial portion of soldiers don’t shoot; they urge focusing on specific conditions and morale factors rather than a single number () ().
Dave Grossman – On Killing (1995)	Synthesis of military history, psychology studies ([Hope on the Battlefield	Greater Good](https://greatergood.berkeley.edu/article/item/hope_on_the_battlefield#:~:text=Why%20did%20these%20men%20fail,before%20they%20can%20overcome%20it)) ([Hope on the Battlefield	Greater Good](https://greatergood.berkeley.edu/article/item/hope_on_the_battlefield#:~:text=demonstrable%20fact%20that%20there%20is%2C,before%20they%20can%20overcome%20it))
British DOAE Study (1986)	UK Defense Operational Analysis of 100+ battles (19th–20th C.) ([Hope on the Battlefield	Greater Good](https://greatergood.berkeley.edu/article/item/hope_on_the_battlefield#:~:text=A%201986%20study%20by%20the,battles%20using%20pulsed%20laser%20weapons))	Compared historical battle casualty rates to simulated battle potential (laser engagements). Found actual kill rates in real battles were far lower than what trained soldiers could achieve in simulations with no risk ([Hope on the Battlefield
Anthropological Cases	Cross-cultural studies of warfare (20th C.) (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia)	Peaceful societies: e.g. !Kung of Kalahari reported to settle conflicts mostly with shouting matches, few injuries (Humankind: A Hopeful History - Wikipedia). Warlike societies: e.g. Yanomamö of Amazon had frequent raids, high murder rates; warriors (allegedly) had more wives/kids (Humankind: A Hopeful History - Wikipedia).	Great variation in cultural attitudes toward violence. Used in debates on whether war is a cultural invention or an innate male strategy. Peaceful cases bolster the view that humans don’t naturally want to kill; warlike cases (though some were later challenged) show that under certain social norms, violence can be prevalent and even incentivized. Scholars caution against generalizing from one society; context (resources, traditions) drives war behavior.
Rutger Bregman – Humankind (2019)	Multi-disciplinary review of historical and scientific evidence (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia)	Argues “humans are decent at heart” and not inclined to violence. Highlights Marshall’s WWII finding (majority of soldiers didn’t fire) and Civil War muskets (widespread non-shooting) as key evidence (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia). Attributes violence to social structures, not basic nature.	Interpretation: Human nature is fundamentally peaceful/cooperative; war requires dehumanization or authority to compel violence. Critiques: Some say Bregman cherry-picks examples and downplays evidence of innate aggression. His take on Pinker and Chagnon is disputed (Humankind: A Hopeful History - Wikipedia) (Humankind: A Hopeful History - Wikipedia). Nevertheless, Humankind has brought the non-killing soldier phenomenon to a broad audience, framing it as a sign of hope and a call to rethink assumptions about brutality being “natural.”