Not every veteran who is exposed to traumatic events develops PTSD. Certain situations are more likely to cause PTSD than other situations. This is particularly true for soldiers who are asked to kill during service.
It is unlikely that the readers of my blog have heard about the science of “killology.” By definition, killology is the study of the psychological effect of killing in combat and a description of factors that actually help to restrain killing others by a combatant.
Research on how human beings kill each other includes sociological studies on groups of people living together that engage in altercations with other groups of people over access to necessary resources such as food and shelter.
A Brief History of Soldier Killology
Generally, Homo sapiens are the only species who engage in the systematic killing of millions and millions of others of the same species. This term, Homo sapiens, is the systematic name of humans in taxonomy. Coined in 1758 by Carl Linnaeus, Homo sapien is Latin for “wise man.”
In all fairness to Dr. Linnaeus - even with the understanding that there was a 30-year war and a 100-year war during medieval times – by 1758, Homo sapiens had not yet progressed to the level of industrial killing that has ramped up in the last 100 years of human history - including the killing of many millions of people in the First World War and Second World War.
The Second World War involved the use of nuclear weapons that then consequently progressed to the concept of mutually-assured destruction during the Cold War. World War II involved mass genocide by Hitler and Stalin. Further on, we became aware of the Cambodian genocide, where approximately 3 million Cambodian people died.
The first textbook written in the field of killology was the Chinese military treatise, The Art of War, written by military strategist Sun Tzu over 1500 years ago.
Later works on the subject include Vom Kriege (On War), published in 1832 by Prussian general and military strategist Carl von Clausewitz. Swiss officer Antoine-Henri Jomini followed up with his work, The Art of War, in 1838, its contents utilized by officers at West Point.
A review of the American Civil War further enhanced the study of killology. Regarding casualties as a percentage of our population, the American Civil War was clearly our most deadly military encounter.
PTSD doesn’t always involve killing. Mere observation of human suffering can be traumatic enough to cause the changes in the brain that occur in PTSD patients. The available literature shows that many wounded Civil War soldiers did not receive timely medical care and eventually died of their wounds or other external factors.
Reports describe Civil War soldiers as experiencing very severe stress while they were lying wounded on the ground, hearing and observing cries and screams from other soldiers who lay in ditches too injured to move. Water from heavy rains accumulated in the ditches, slowly drowning the wounded men.
It’s important to realize that the traumatic stress many of these soldiers experienced came as a result of situations not involved in active killing, but in observing the suffering and gradual death occurring around them.
Justified Versus Unjustified Killing Alters Brain Activity
A discussion of killology starts to merge the borders of psychiatry with normal and abnormal psychology. It brings us into the territory involving scientific data about what actually happens in the brains of Homo sapiens who kill other Homo sapiens.
Of interest here is a 2015 study published in the Journal of Social, Cognitive and Affective Neuroscience conducted by Dr. Pascal Molenberghs at Monash University in Melbourne, Australia.
The Monash study examined 48 individuals by functional magnetic resonance imaging. Researchers had the volunteers watch three different scenarios on video during the brain scans.
- A soldier killing an enemy soldier
- A soldier killing a civilian
- A soldier shooting a weapon but not hitting anyone
Participants were told to imagine that they were performing the action. All videos were filmed from the shooter's point of view. After watching each video, the participants were asked, “Who did you shoot?” and had to respond with soldier, civilian or nobody.
Depending on who was shot and killed, the brain scans showed activity differences within specific areas of the brain. When the volunteers were killing a soldier, there was more significant activity in more areas of the brain.
The area of the forebrain called the orbitofrontal cortex exhibited a significant amount of activity during the killing scenarios. This part of the brain is involved in moral sensitivity, moral judgment, and making choices about how to behave.
Interestingly, the orbitofrontal cortex is located near the temporoparietal junction, an area of the brain implicated in complex moral reasoning (like when a person does something deliberately and then has a sense of responsibility for doing it).
The data from the Monash study shows that there is a tremendous difference in how we deal with our actions, depending on whether we are justified in performing them. Results showed that the orbitofrontal cortex is less active when the violence is seen as justified. When a soldier killed an enemy, the brain was less active than it was when the soldier killed a civilian.
In other words, after shooting a civilian, the orbitofrontal cortex concluded, "I feel guilty." The temporoparietal junction then severely activated a response that said, "You should feel guilty."
Further, when the video involved shooting a helpless civilian, an additional part of the brain was activated, the fusiform gyrus.
We now know that the fusiform gyrus is the part of the brain that involves analyzing faces, suggesting the study volunteers actually studied the expressions on the faces of these imaginary victims when they were shot. This means the volunteers watching the civilian shootings were much more significantly disturbed.
Based on a review of this data, if we consider it justifiable to kill someone (for example if you thought they were planning to kill you), a different, more business-like part of the brain is implicated.
Conversely, when the situation involves a non-justifiable killing, the killer’s brain actually analyzes the face of the victim. The fusiform gyrus creates a much more significant disturbance in the overall functioning of the brain.
Interestingly, the findings of this study help us understand the inner workings of the soldier’s brain, and how PTSD develops after a soldier is faced with killing other human beings in a variety of scenarios.
For those of you who want to learn more about the science of killology, I encourage you to read the book On Killing: The Psychological Cost of Learning to Kill in War and in Society, written by retired Army Lieutenant Colonel David Grossman.
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