On Killing: The Psychological Cost of Learning to Kill in War and Society

by Dave Grossman

The key understanding to take away from this litany of mental illness is that within a few months of sustained combat some symptoms of stress will develop in almost all participating soldiers.

If I had time and anything like your ability to study war, I think I should concentrate almost entirely on the “actualities of war”—the effects of tiredness, hunger, fear, lack of sleep, weather…. The principles of strategy and tactics, and the logistics of war are really absurdly simple: it is the actualities that make war so complicated and so difficult, and are usually so neglected by historians. —Field Marshal Lord Wavell, in a letter to Liddell Hart

But clinical studies that tried to demonstrate that fear of death and injury are responsible for psychiatric casualties have been consistently unsuccessful.

great emphasis on “letting others down.”

battle. His conclusion was that combat experience decreases fear of death or injury.

it is instead the fear of not being able to meet the terrible obligations of combat that weighs most heavily on the minds of combat soldiers.

Fear of death and injury is not the only, or even the major, cause of psychiatric casualties in combat.

Fear, combined with exhaustion, hate, horror, and the irreconcilable task of balancing these with the need to kill, eventually drives the soldier so deeply into a mire of guilt and horror that he tips over the brink into that region that we call insanity.

During World War I the probability of a soldier becoming a psychiatric casualty was greater than that of his being killed by enemy fire.

This strategic bombing of population centers was motivated by quite reasonable expectations of mass psychiatric casualties resulting from the strategic bombing of civilian populations. But they were wrong.

bombing seemed to have served primarily to harden the hearts and empower the killing ability of the nations that endured it.

Gabriel notes that studies from both the First and Second World Wars show that prisoners of war did not suffer psychiatric reactions when they were subjected to artillery attack or aerial bombardment, but their guards did.

combatants will try to get out of the battle (a situation where they are required to kill) even when it puts them at risk.

that the prisoners “had shifted responsibility for their survival to the guards.”

The guards, on the other hand, took the matter as a personal affront. They still had a capacity and a responsibility to fight, and they were faced with the irrefutable evidence that someone was intent on killing them and that they had a responsibility to do likewise.

the unbearable responsibility inherent in their roles as soldiers.

The answer is, again, that most of them don’t have to kill anyone directly, and no one is trying to specifically, personally, kill them.

Thus, although recon patrols are dangerous, and the information produced may result in many enemy soldiers being killed, the mission itself is a very benign operation.

Soldiers on patrols behind enemy lines—like civilians suffering from strategic bombing, prisoners of war receiving artillery or bombs, and sailors in modern naval combat—generally do not suffer psychiatric stress because, for the most part, the element that is most responsible for causing combat stress is not present: they are not obligated to engage in face-to-face aggressive activities against the enemy. Even though these missions are highly dangerous, danger and the fear of death and injury are quite obviously not the predominant cause of psychiatric casualties in battle.

nonkilling military personnel on the battlefield suffer fewer psychiatric casualties than those whose job it is to kill.

but perhaps a large part of the answer is that he simply was not obligated to kill.

His harrowing adventures rescuing and giving medical aid to downed pilots, he quite freely admitted, was a relief from, and a very powerful personal penance for, his relatively brief experience as a killer.

Officers direct the killing but very seldom participate in it.

(in World War I, the probability of a British officer becoming a psychiatric casualty was half that of the men).

the officer also has a far smaller burden of individual responsibility for killing on the battlefield. The key difference is that he doesn’t have to do it personally.

The stress factors that soldiers experienced and bombing victims did not were the two-edged responsibility of (1) being expected to kill (the irreconcilable balancing of to kill and not to kill) and (2) the stress of looking their potential killers in the face (the Wind of Hate).

Sunken cheeked and hollow eyed, we were in a state of total starvation-enhanced exhaustion that caused many of us to have repeated hallucinations. These were incredibly vivid dreams that we would experience while wide-awake.

Only pride and determination kept us going.

The four factors of (1) physiological arousal caused by the stress of existing in what is commonly understood as a continual fight-or-flight-arousal condition, (2) cumulative loss of sleep, (3) the reduction in caloric intake, and (4) the toll of the elements—such as rain, cold, heat, and dark of night—assaulting the soldier all combine to form the “state of prolonged and great fatigue” that is the Weight of Exhaustion.

This process is so intense that soldiers very often suffer stress diarrhea, and it is not at all uncommon for them to urinate and defecate in their pants as the body literally “blows its ballast” in an attempt to provide all the energy resources required to ensure its survival.

This parasympathetic backlash occurs as soon as the danger and the excitement is over, and it takes the form of an incredibly powerful weariness and sleepiness on the part of the soldier.

It is basically for this reason that the maintenance of fresh reserves has always been essential in combat, with battles often revolving around which side can hold out and deploy their reserves last.

In continuous combat the soldier roller-coasters through seemingly endless surges of adrenaline and subsequent backlashes, and the body’s natural, useful, and appropriate response to danger ultimately becomes extremely counterproductive. Unable to flee, and unable to overcome the danger through a brief burst of fighting, posturing, or submission, the bodies of modern soldiers quickly exhaust their capacity to energize and they slide into a state of profound physical and emotional exhaustion of such a magnitude and dimension that it appears to be almost impossible to communicate it to those who have not experienced it.

“that lack of food constitutes the single biggest assault upon morale…. Apart from its purely chemical effects upon the body, it has woeful effects upon the mind.”

lack of sleep, lack of food, the impact of the elements, and emotional exhaustion caused by constant fight-or-flight-response activation

the combat soldier appears to feel a deep sense of responsibility and accountability for what he sees around him. It is as though every enemy dead is a human being he has killed, and every friendly dead is a comrade for whom he was responsible.

they come back to haunt your nights in your old age.

We want desperately to be liked, loved, and in control of our lives; and intentional, overt, human hostility and aggression—more than anything else in life—assaults our self-image, our sense of control, our sense of the world as a meaningful and comprehensible place, and, ultimately, our mental and physical health.

It is not fear of death and injury from disease or accident but rather acts of personal depredation and domination by our fellow human beings that strike terror and loathing in our hearts.

suicide, these men would rather die or mutilate themselves than face the aggression and hostility of a very hostile world.

The distinguishing characteristic here, as opposed to numerous other noncombatant circumstances marked by an absence of psychiatric casualties, is that those in concentration camps had to face aggression and death on a highly personal, face-to-face basis. Nazi Germany placed a remarkable concentration of aggressive psychopaths in charge of these camps, and the lives of these victims were completely dominated

Unlike the victims of aerial bombing, the victims of these camps had to look their sadistic killers in the face and know that another human being denied their humanity and hated them enough to personally slaughter them, their families, and their race as though they were nothing more than animals.

But in the death camps it was starkly, horribly personal. Victims of this horror had to look the darkest, most loathsome depths of human hatred in the eye. There was no room for denial, and the only escape was more madness.

Not only does the average soldier’s psyche resist killing and the obligation to kill, but he is equally horrified when exposed to the aggression of an enemy who hates him and denies his humanity enough to kill him.

What maneuver warfare advocates have discovered is that over and over in history, civilians and soldiers have withstood the actuality of fear, horror, death, and destruction during artillery bombardments and aerial bombardments without losing their will to fight, while the mere threat of invasion and close-up interpersonal aggression has consistently turned whole populations into refugees fleeing in panic.

The potential of close-up, inescapable, interpersonal hatred and aggression is more effective and has greater impact on the morale of the soldier than the presence of inescapable, impersonal death and destruction.

the inoculation is specifically oriented toward hate.

He has become partially inoculated against hate.

nations. By understanding the role of hate on the battlefield, we now can finally and truly understand the military value of what armies have done for so long and some of the processes by which they have enabled the soldier to physically and psychologically survive on the battlefield.

emotional stamina on the battlefield as a finite resource. I have termed this the Well of Fortitude.