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Natural Killers —
Turning the Tide of Battle
Major David S. Pierson, US Army
Turning the Tide of Battle
3rd Place 1997 McArthur Award Winner
I STEPPED OVER TO GREET the tank company
commander as he approached the tactical operations
center. This man was a neighbor and a friend,
but he was not the same soldier I had briefed three
days earlier. After 72 hours of combat, his eyes
were sunken and dark. The left side of his face was
stained with iodine and bandaged to cover a bullet
wound received 14 hours earlier. He was distant
and detached as he described an incident that had
occurred just hours before. His company had engaged
two Iraqi trucks moving across its front. The
trucks exploded and Iraqi soldiers leapt out of them
on fire. The company then finished them off with
coaxial machineguns and a single sabot round that
vaporized the soldier it hit. My friend was clearly
shaken by the episode. This man was a warrior.
Circumstances had made him a killer.
My friend wasn’t a natural killer. A natural killer is
a person who has a predisposition to kill—he enjoys
combat and feels little or no remorse about killing the
enemy. These men have existed throughout the history
of warfare, and their feats have often been hailed
as heroic. They constitute less than 4 percent of the
force, yet some studies show that they do almost half
of the killing. These men rarely distinguish themselves
before the moment arrives to pull the trigger. It is only
after the smoke has cleared that the full impact of their
accomplishment is seen. It is important to identify natural
killers before combat, because these soldiers are
both a vital asset and a potential liability—correctly
positioning them in a unit can turn the tide of battle.
To better understand the importance of identifying
these soldiers, one should understand what makes
soldiers kill, the characteristics of natural killers and
their battlefield capabilities and limitations.
Thou Shall Not Kill
Most soldiers are unknowingly conscientious objectors.
1 They try to avoid taking a human life. This
is not a bad thing. Rather, it is a reflection of a
strong moral upbringing. Getting most soldiers to
pull the trigger on another human being requires
great effort. In World War II, General S.L.A.
Marshall studied infantry unit firing ratios and concluded
that only 15 to 25 percent of infantrymen
ever fired their weapons in combat. In general,
those on specialty and crew-served weapons were
firers, while the nonfirers were almost exclusively
riflemen.2 In On Killing, David Grossman points
out that there are three things that make soldiers kill:
conditioning, recent experience and temperament.3
Soldiers can be conditioned individually and collectively
to pull the trigger. Individual conditioning
includes gunnery and rifle ranges where popup
human shaped targets are rapidly engaged without
thought. The trigger-pull response becomes automatic.
Close supervision also affects firing rates. Men pull
the trigger more frequently under supervision or in
groups, hence a higher ratio of firing among key
weapons. Artillery, the greatest killer on the battlefield,
has always killed in teams. We indirectly condition
soldiers to kill by training them as killing
teams. Recognizing that men had to be conditioned
to fire, the Army changed its training programs after
World War II, and firing rates during the Korean
War rose to 55 percent.4 This figure reached
95 percent during the Vietnam War.5 Soldiers can
Recent experiences, such as the death
of a comrade, can cause soldiers to kill the
enemy out of revenge or frustration. This is a
temporary condition resulting from combat
stress. It is based upon emotion and can subside
as quickly as it occurred. . . . While we may
attempt to emotionally condition soldiers
through propaganda, it has little long-term
effect on them on the battlefield.
The views expressed in this article are those of the author and do not
purport to reflect the position of the Department of the Army; the Department
of Defense or any other government office or agency.—Editor
60 May -June 1999 l MILITARY REVIEW
MILITARY REVIEW l May-June 1999 61
be taught to pull the trigger, but that does not guarantee
that the bullet will find the target.
Recent experiences, such as the death of a comrade,
can cause soldiers to kill the enemy out of revenge
or frustration. This is a temporary condition
resulting from combat stress. It is based upon emotion
and can subside as quickly as it occurred. In
an American field hospital in Vietnam, a wounded
Vietcong dragged himself out of bed and used a
broken bottle to slit the throat of an Australian lying
next to him. The American doctor, who had
worked for hours to save the Australian’s life,
grabbed a .45, shoved it in the Vietcong’s mouth
and, with no regard for the Hippocratic Oath, blew
his brains out. When he realized what he had
done, he went insane and had to be shipped home.6
While we may attempt to emotionally condition
soldiers through propaganda, it has little long-term
effect on them on the battlefield.
A temperament for killing exists among some
human beings. Marshall, in identifying the battlefield
fighters, said, “the same names continued to
reappear as having taken the initiative, and relatively
few fresh names were added to the list on any day.”7
A post-World War II study by R. L. Swank and
W. E. Marchand proposed that 2 percent of soldiers
were “aggressive psychopaths” who did not suffer
from the normal remorse or trauma associated with
killing.8 I use the word suffer because when the job
of the soldier is to kill, those fettered by their conscience
are suffering while doing their job. We tend
to shun the concept of the willing killer because
it offends our kinder sensibilities, but a controlled
psychopath is an asset on the killing fields. Those
who possess such a temperament are natural killers
and many have served this country well. The problem
lies in identifying these individuals and positioning
them where they can be most effective.
Killers Among Us
The term psychopath conjures up images of movies
such as Psycho or Silence of the Lambs. There
are less inflammatory terms such as sociopath, US Army
Most soldiers are unknowingly conscientious objectors. They try to avoid taking a
human life. This is not a bad thing. Rather, it is a reflection of a strong moral upbringing.
Getting most soldiers to pull the trigger on another human being requires great effort. In World War
II, General S.L.A. Marshall studied infantry unit firing ratios and concluded that only 15 to 25
percent of infantrymen ever fired their weapons in combat. In general . . . there are three things
that make soldiers kill: conditioning, recent experience and temperament.
A chaplain provides field service to soldiers
of the 101st Airborne Division (Air Assault).
62 May -June 1999 l MILITARY REVIEW
antisocial personality type or undercontrolled personality
type that apply to the same people. The
meanings of these terms have changed and interchanged
over the last half-century. Psychopath is
now associated almost exclusively with violent actions
rather than a propensity for violence.9 The last
three terms are still used somewhat interchangeably
to denote someone who lacks social emotions and
often resorts to violence, deception or manipulation
as a means to get what he wants. These people constitute
3 to 4 percent of the male population and 1
percent of the female.10 Such people who enter the
military are not monsters waiting to be released.
They can be level-headed, productive soldiers, and
if put into the right situation, they will kill the enemy
aggressively and without remorse. If these
soldiers are in our units, how can we identify them?
A predisposition to kill is the result of genetics
and early childhood experience. There are common
traits that are indicative of natural killers. While the
collection of these traits is not absolutely deterministic
of a killer, it is a good framework for identifying
those who may have this propensity. In general,
the natural killer found in the US Army lacks
social emotions, is a later son (not first-born), got
into frequent fights as a child, enjoys contact sports,
is from a middle or upper class background, is an
extrovert, has above-average intelligence and a caustic
sense of humor.
While no specific violence gene has yet been isolated,
there is ample evidence to suggest that violent
tendencies are inherited. Researcher D.C. Rowe
posits that some individuals have a genotype that
disposes them to antisocial behavior.11 These individuals
are characterized by a deficit of social emotions
which include love, shame, guilt, empathy and
remorse. They are keen predictors of other people’s
behavior. Unbridled by emotions, they rely solely
on actuarial data to predict outcomes, never resorting
to feelings or hunches.12 They focus on shortterm
outcomes without taking into account the emotional
reactions of those with whom they are dealing.
Thus they may come across as cold, impersonal
and manipulative.
As previously mentioned, the natural killer is most
likely not a first-born son. Later sons are generally
more aggressive and have less fear or anxiety in
dangerous situations. An Israeli Defense Force
study of its officers from 1961 to 1966 showed that
“first borns” were more anxious than “later borns”
and that they generally sought less dangerous positions
in the military. Later borns were more likely
to volunteer for combat and had a better chance of
encountering terrorists on patrols.13 A study of Korean
War fighter plane aces found that first borns
engaged the enemy less and were more anxious
about flying.14 Family position also seems to relate
to assassins. Almost all American assassins have
been later sons—John Wilkes Booth, Charles Giteau
and Lee Harvey Oswald, to name three.15 Later
borns, by virtue of being routinely dominated by
their siblings, ultimately feel less fear during stressful
situations. They also feel the need to prove their
worth over their siblings and more quickly accept
dangerous challenges.
A natural killer has been a fighter for much of
his life. Frequent fighting as a child does not mean
the individual was a bully. Rather, he chose to respond
to stressful situations with aggression.16
Arthur J. Dollard concluded that aggression is the
result of frustration and this is a normal human reaction.
17 The sociopath, also referred to as the
undercontrolled aggressive personality type, has low
internal controls against violence and will resort to
aggressive behavior unless constrained by rigid external
controls. Such a person can be conditioned
to not respond to frustration with external aggression.
18 Thus, if frustrated by a Drill Sergeant’s control,
the undercontrolled personality type will refrain
from direct aggression and look for another target for
his aggression. The military provides ample displacement
outlets for this aggression in the form of physical
training, field maneuvers and weapons ranges. It is the
perfect environment for a sociopath to excel.
The natural killer is an aggressive athlete whose
physical makeup allows him to excel at contact
sports. Combative sports provide long-term training
in aggression while acting as a short-term catharsis
or safety valve for aggressive individuals.19 An Armyfunded
study of Korean War veterans discerned differences
in the characteristics of fighters—those
who took aggressive action in combat—versus
nonfighters—those who were hysterical or nonre-
There are common traits that are indicative
of natural killers. While the collection of these
traits is not absolutely deterministic of a killer,
it is a good framework for identifying those who
may have this propensity. In general, the
natural killer found in the US Army lacks social
emotions, is a later son (not first-born), got into
frequent fights as a child, enjoys contact sports,
is from a middle or upper class background, is
an extrovert, has above-average intelligence
and a caustic sense of humor.
MILITARY REVIEW l May-June 1999 63
sponsive in combat. This study, conducted by the
Human Resources Research Office (HumRRO), concluded
that the fighters had been more active in contact
sports such as football, boxing or hockey. It also
concluded that fighters had a high masculinity factor
or outdoors adventurousness about them. Their
body types were larger; on average they were an inch
taller and eight pounds heavier than the nonfighters.20
They were rugged individuals who had channeled
their aggressions through contact sports.
Another discriminator for identifying natural killers
is their socio-economic background. Natural
killers usually come from a middle or upper class
background. The volunteer military has had the
luxury to pick and choose those who will be allowed
into the service, and we exclude those with criminal
records. Sociopaths follow a “cheater strategy”
to obtain what they want.21 The lack of a social conscience
allows the sociopath to cheat without remorse.
Consequently, those who find themselves
in the economically disadvantaged lower class will
resort to crime unless placed in a highly controlled
environment. In other words, a sociopath from a
depressed economic background will most likely
have a criminal record, and under today’s standards,
he would not be able to enter the military. Thus,
natural killers in the US military will most likely
come from a middle or upper class background.
Sociopaths are generally extroverts. One reason
for this is the inheritance of a nervous system that US Army
There are several considerations for the positioning of natural killers in the unit.
If they are junior enlisted personnel, they should be assigned to a crew-served weapon. This will
provide them with ample firepower and place them in a position to motivate others. They will
naturally seek this position out anyway. If the natural killer is a noncommissioned officer or
officer, assign him to a leadership position where he will supervise trigger pullers and will
have a weapon system at his disposal. Here they will lead by example, killing the enemy
and motivating others to do so as well.
Soldiers of the 193d Infantry
Brigade prepare to return fire
during Operation Just Cause,
December 1990.
64 May -June 1999 l MILITARY REVIEW
is relatively insensitive to low levels of stimulation.
Individuals with this physiotype tend to be extroverted.
22 They also have lower than average levels
of adrenaline and seek experiences to heighten this.
Extroverts and sociopaths are less affected by threats
of pain or punishment, and they have greater tolerance
of actual pain or punishment. Both sociopaths and extroverts
will approach a situation that most people
will avoid.23 These factors were confirmed by the
HumRRO study conclusion that fighters were extroverted,
spontaneous and relatively free from anxiety.24
The natural killer has above-average intelligence.
Like sociopaths with no economic resources, those
without above-average intelligence end up in jail.
Therefore, sociopaths in our military are usually intelligent.
The HumRRO study found that the intelligence
quotient (IQ) of fighters was, on average,
13 points higher than nonfighters’. The study subjects
were all infantrymen and the mean group IQ
was only 85, 15 points below the national average
of 100. This indicated that less intelligent men were
sent forward to fight, but within that group, the more
intelligent ones were better fighters.25
Additionally, the natural killer has a caustic sense
of humor that relies on sharp wit and biting sarcasm.
26 Such hostile humor acts as a tension-discharger,
a relief valve. While we normally associate
humor with friendly behavior, laughter itself is
a primarily aggressive behavior. Laughter is usually
directed at someone and is infectious, with the
unspoken agreement being to “join in or not be part
of the group.”27 With aggression as the underlying
theme, the natural killer enjoys humor.
Potential natural killers can be identified through
long-term observation testing. Supervisors can look for
natural killer traits in their soldiers. Over time, they will
develop a close enough relationship with their soldiers
to be able to distinguish those who match most of the
characteristics of killers. Personality-type testing
may also identify natural killers. One such test already
in use by the military is the Myers-Briggs personalitytype
test. Considering the characteristics discussed
above, the natural killer would most likely be an ESTP
(extroverted, sensory, thinking, perceiving) personality
type on this test. ESTPs are outgoing, highly
adaptive, deal in facts, sensory oriented, excel at
sports, learn through life experience, prefer action
to conversation and are tough in harsh situations.28
Matching the ESTP personality type to intelligent,
caustic, later sons will help identify potential natural
killers. The ESTP personality type, coupled with
the other associated traits, is not an absolute determinant
of a natural killer or a sociopath, but it provides
a good baseline. Personality-type testing at
initial entry could identify and help place natural
killers where they can best employ their talent—in
infantry, armor and special operations units.
Cry Havoc
The individual soldier does make a difference on
the killing fields. The natural killer is a vital asset
to a unit because he is a killing machine that will
turn the tide of battle when the chips are down.
During World War II, 40 percent of the US Army
Air Forces’ air-to-air killing was done by 1 percent
of its pilots.29 Marshall’s work and the HumRRO
study both found that a small percentage of soldiers
did most of the fighting. It is not enough to rely on
conditioning to produce killers—genetics and childhood
environment have already molded them.
Natural killers bring some obvious advantages to
a unit. They will personally kill the enemy in
droves. They are natural leaders who will motivate
other soldiers to kill. They are also fiercely competitive
and will aggressively pursue victory. In a
battle of attrition, the natural killer can singlehandedly
tip the scales. However, there are drawbacks
to natural killers in a unit too. Their highly
aggressive nature may act as a catalyst for violence
in tenuous situations such as peacekeeping (PK) operations.
This is not to say that they will create
atrocities, which are generally initiated by overcontrolled
personality types in second-in-command
positions, not by undercontrolled personality types.30
Atrocities are the result of the release of pent-up
hostilities—not a characteristic of sociopaths who
live for the moment. Natural killers may participate
in atrocities but they will not initiate them. This
same “live-for-the-moment” attitude makes the
peacetime routine difficult for killers. The sociopath
craves stimulation that the peacetime Army
often does not provide. Marshall concluded that
many of the best fighters spent significant amounts
of time in the stockade—“They could fight like hell
Natural killers bring some obvious
advantages to a unit. They will personally kill
the enemy in droves. They are natural leaders
who will motivate other soldiers to kill. They are
also fiercely competitive and will aggressively
pursue victory. . . . However, there are drawbacks
to natural killers in a unit too. Their
highly aggressive nature may act as a catalyst for
violence in tenuous situations such as peacekeeping
operations.
MILITARY REVIEW l May-June 1999 65
but they couldn’t soldier.”31 Consequently, many of
these individuals seek out fast-paced specialty units
such as Airborne, Ranger or Special Forces units.32
The natural killer will become bored in a regular unit
and may seek the stimuli of sports, fighting or drugs.
Natural killers are motivated by competition and excitement,
not a sense of sacrifice—they are not the kind
of soldiers who will leap on a grenade to protect others.
Another characteristic of the natural killer is to
usurp authority in a crisis to turn the tide of battle.
Marshall wrote of a sergeant whose actions had carried
the battle and yet he had not been recommended
for a decoration. When his company commander
was asked why, he replied, “When the fighting
started he practically took the company away from
me. He was leading and the men were obeying him.
You can’t decorate a man who’ll do that to you.”33
There are several considerations for the positioning
of natural killers in the unit. If they are junior
enlisted personnel, they should be assigned to a
crew-served weapon. This will provide them with
ample firepower and place them in a position to
motivate others. They will naturally seek this position
out anyway. If the natural killer is a noncommissioned
officer or officer, assign him to a leadership
position where he will supervise trigger pullers
and will have a weapon system at his disposal. Here
they will lead by example, killing the enemy and
motivating others to do so as well.
Natural killers may be spread out in the unit or
concentrated, depending on the tactical situation.
The typical officer cannot single-handedly lead an
entire company in combat.34 By spreading out those
who will carry the day you increase your chances
for success in battle. Wherever they are placed in a unit
though, they may take over command based upon the
situation and the leaders around them. This may be
desirable depending upon the quality and number
of your other leaders. You can “backstop” leaders
of unproved ability with natural killers. If there is
a well-defined decisive point of the battle, the commander
may choose to place natural killers at that
point. They will provide that final measure of resolve
in the assault or become the defense linchpin.
Since natural killers are motivated by competition
and excitement, they should not be placed in a reserve
position, where they would have to patiently
wait, then hurl themselves into the breach on command.
Quick to take charge, they will move to the sound of
the guns unless tightly controlled. In PK operations,
keep them in positions where they will not habitually
deal with potential combatants. This will minimize the
risk of escalating the tension into violence. Likewise,
during peacetime operations, keep them active
in exercises, schools or in sports. They will seek
out these activities themselves to stay stimulated.
Too often we find out about the lethality of an
individual soldier after the fact, when he has saved
the unit and been nominated for a valorous award.
If you knew before hand who was likely to rise up
and save the day, you could place these soldiers at
the battle’s decisive point and enhance your chances
of success. Natural killers are out there in your unit
right now—find them and use them wisely. MR
Major David S. Pierson is the 165th Military Intelligence Battalion XO, Darmstadt, Germany.
He received a B.A. from the University of Georgia and an M.A. from Webster University,
and he is a graduate of the US Army Command and General Staff College (CGSC). He has
held a variety of command and staff positions in the Continental United States and Germany,
including G2 operations officer, V Corps, Heidelberg, Germany; chief, collection management,
United States Transportation Command, Scott Air Force Base, Illinois; and commander,
A Company, 124th Military Intelligence Battalion, Fort Stewart, Georgia.
NOTES
1. S.L.A. Marshall, Men Against Fire: The Problem of Battle Command in Future
War (Washington DC: Infantry Journal Press, 1947, reprint Gloucester, MA:
Peter Smith, 1978), 79.
2. Ibid., 56-57.
3. Dave Grossman, On Killing: The Psychological Cost of Learning to Kill in
War and Society (Boston, MA: Little, Brown, and Company, 1996), 177-85.
4. Marshall, 9.
5. Grossman, 35.
6. Mark Baker, Nam (New York: William Morrow and Company, 1981), 161-62.
7. Marshall, 58-59.
8. Swank and Marchand, in On Killing, 180.
9. Ralph Serin, “Can Criminal Psychopaths be Identified?” FORUM 1989, Volume
1, Number 2.
10. C.C. Strauss and B.B. Lahey in: The Sociobiology of Sociopathy: An Integrated
Evolutionary Model, Linda Mealey, unedited penultimate draft of an article
accepted for publication (Copyright 1994: Cambridge University Press).
11. D.C. Rowe, “Inherited dispositions toward learning delinquent and criminal
behavior: New evidence,” in Crime in biological, social, and moral contexts, ed.
L. Ellis and H. Hoffman (Praeger Publications, November 1990), 122.
12. Linda Mealey, in The Sociobiology of Sociopathy, 3.
13. Peter Watson, War on the Mind: The Military Uses and Abuses of Psychology
(New York: Basic Books Inc., 1978), 51.
14. E.P. Torrence, The development of preliminary life-experience inventory for
the study of fight-interceptor combat effectiveness, Research Bulletin AFPTRCTR-
54-89, Lackland Air Force Base, San Antonio, TX, December 1954.
15. Irving D. Harris, Violence: Perspectives on Murder and Aggression (San
Francisco: Jossey-Bass Publishers), ed. Irwin L. Kutash, Samuel B. Kutash and
Louis B. Schlesinger, 203.
16. Grossman, 182.
17. J. Dollard et al., Frustration and Aggression (New Haven, CT: Yale University
Press, 1939).
18. Edwin I. Magargee and Jack E. Hokanson, The Dynamics of Aggression: Individual,
Group and International Analyses (New York: Harper & Row, 1970), 111.
19. Irenaus Eibl-Eibesfeldt, The Biology of Peace and War: Men, Animals, and
Aggression (New York: The Viking Press, 1979), translated from German by Eric
Mosbacher (R. Piper & Co., Munich), 110-11.
20. Watson, 49-50.
21. Mealey, 33.
22. Ibid., 17.
23. Ibid., 14.
24. Watson, 49.
25. Ibid.
26. Ibid.
27. Eibl-Eibesfeldt, 90.
28. Isabel Briggs Myers, Gifts Differing (Palo Alto, CA: Consulting Psychologists
Press, 1980), 101-104.
29. Grossman, 181.
30. Watson, 245.
31. Marshall, 60-61.
32. Grossman, 181.
33. Marshall, 62.
34. Ibid.
OPERATIONAL LEADERSHIP
Natural Killers —
Turning the Tide of Battle
Major David S. Pierson, US Army
Turning the Tide of Battle
3rd Place 1997 McArthur Award Winner
I STEPPED OVER TO GREET the tank company
commander as he approached the tactical operations
center. This man was a neighbor and a friend,
but he was not the same soldier I had briefed three
days earlier. After 72 hours of combat, his eyes
were sunken and dark. The left side of his face was
stained with iodine and bandaged to cover a bullet
wound received 14 hours earlier. He was distant
and detached as he described an incident that had
occurred just hours before. His company had engaged
two Iraqi trucks moving across its front. The
trucks exploded and Iraqi soldiers leapt out of them
on fire. The company then finished them off with
coaxial machineguns and a single sabot round that
vaporized the soldier it hit. My friend was clearly
shaken by the episode. This man was a warrior.
Circumstances had made him a killer.
My friend wasn’t a natural killer. A natural killer is
a person who has a predisposition to kill—he enjoys
combat and feels little or no remorse about killing the
enemy. These men have existed throughout the history
of warfare, and their feats have often been hailed
as heroic. They constitute less than 4 percent of the
force, yet some studies show that they do almost half
of the killing. These men rarely distinguish themselves
before the moment arrives to pull the trigger. It is only
after the smoke has cleared that the full impact of their
accomplishment is seen. It is important to identify natural
killers before combat, because these soldiers are
both a vital asset and a potential liability—correctly
positioning them in a unit can turn the tide of battle.
To better understand the importance of identifying
these soldiers, one should understand what makes
soldiers kill, the characteristics of natural killers and
their battlefield capabilities and limitations.
Thou Shall Not Kill
Most soldiers are unknowingly conscientious objectors.
1 They try to avoid taking a human life. This
is not a bad thing. Rather, it is a reflection of a
strong moral upbringing. Getting most soldiers to
pull the trigger on another human being requires
great effort. In World War II, General S.L.A.
Marshall studied infantry unit firing ratios and concluded
that only 15 to 25 percent of infantrymen
ever fired their weapons in combat. In general,
those on specialty and crew-served weapons were
firers, while the nonfirers were almost exclusively
riflemen.2 In On Killing, David Grossman points
out that there are three things that make soldiers kill:
conditioning, recent experience and temperament.3
Soldiers can be conditioned individually and collectively
to pull the trigger. Individual conditioning
includes gunnery and rifle ranges where popup
human shaped targets are rapidly engaged without
thought. The trigger-pull response becomes automatic.
Close supervision also affects firing rates. Men pull
the trigger more frequently under supervision or in
groups, hence a higher ratio of firing among key
weapons. Artillery, the greatest killer on the battlefield,
has always killed in teams. We indirectly condition
soldiers to kill by training them as killing
teams. Recognizing that men had to be conditioned
to fire, the Army changed its training programs after
World War II, and firing rates during the Korean
War rose to 55 percent.4 This figure reached
95 percent during the Vietnam War.5 Soldiers can
Recent experiences, such as the death
of a comrade, can cause soldiers to kill the
enemy out of revenge or frustration. This is a
temporary condition resulting from combat
stress. It is based upon emotion and can subside
as quickly as it occurred. . . . While we may
attempt to emotionally condition soldiers
through propaganda, it has little long-term
effect on them on the battlefield.
The views expressed in this article are those of the author and do not
purport to reflect the position of the Department of the Army; the Department
of Defense or any other government office or agency.—Editor
60 May -June 1999 l MILITARY REVIEW
MILITARY REVIEW l May-June 1999 61
be taught to pull the trigger, but that does not guarantee
that the bullet will find the target.
Recent experiences, such as the death of a comrade,
can cause soldiers to kill the enemy out of revenge
or frustration. This is a temporary condition
resulting from combat stress. It is based upon emotion
and can subside as quickly as it occurred. In
an American field hospital in Vietnam, a wounded
Vietcong dragged himself out of bed and used a
broken bottle to slit the throat of an Australian lying
next to him. The American doctor, who had
worked for hours to save the Australian’s life,
grabbed a .45, shoved it in the Vietcong’s mouth
and, with no regard for the Hippocratic Oath, blew
his brains out. When he realized what he had
done, he went insane and had to be shipped home.6
While we may attempt to emotionally condition
soldiers through propaganda, it has little long-term
effect on them on the battlefield.
A temperament for killing exists among some
human beings. Marshall, in identifying the battlefield
fighters, said, “the same names continued to
reappear as having taken the initiative, and relatively
few fresh names were added to the list on any day.”7
A post-World War II study by R. L. Swank and
W. E. Marchand proposed that 2 percent of soldiers
were “aggressive psychopaths” who did not suffer
from the normal remorse or trauma associated with
killing.8 I use the word suffer because when the job
of the soldier is to kill, those fettered by their conscience
are suffering while doing their job. We tend
to shun the concept of the willing killer because
it offends our kinder sensibilities, but a controlled
psychopath is an asset on the killing fields. Those
who possess such a temperament are natural killers
and many have served this country well. The problem
lies in identifying these individuals and positioning
them where they can be most effective.
Killers Among Us
The term psychopath conjures up images of movies
such as Psycho or Silence of the Lambs. There
are less inflammatory terms such as sociopath, US Army
Most soldiers are unknowingly conscientious objectors. They try to avoid taking a
human life. This is not a bad thing. Rather, it is a reflection of a strong moral upbringing.
Getting most soldiers to pull the trigger on another human being requires great effort. In World War
II, General S.L.A. Marshall studied infantry unit firing ratios and concluded that only 15 to 25
percent of infantrymen ever fired their weapons in combat. In general . . . there are three things
that make soldiers kill: conditioning, recent experience and temperament.
A chaplain provides field service to soldiers
of the 101st Airborne Division (Air Assault).
62 May -June 1999 l MILITARY REVIEW
antisocial personality type or undercontrolled personality
type that apply to the same people. The
meanings of these terms have changed and interchanged
over the last half-century. Psychopath is
now associated almost exclusively with violent actions
rather than a propensity for violence.9 The last
three terms are still used somewhat interchangeably
to denote someone who lacks social emotions and
often resorts to violence, deception or manipulation
as a means to get what he wants. These people constitute
3 to 4 percent of the male population and 1
percent of the female.10 Such people who enter the
military are not monsters waiting to be released.
They can be level-headed, productive soldiers, and
if put into the right situation, they will kill the enemy
aggressively and without remorse. If these
soldiers are in our units, how can we identify them?
A predisposition to kill is the result of genetics
and early childhood experience. There are common
traits that are indicative of natural killers. While the
collection of these traits is not absolutely deterministic
of a killer, it is a good framework for identifying
those who may have this propensity. In general,
the natural killer found in the US Army lacks
social emotions, is a later son (not first-born), got
into frequent fights as a child, enjoys contact sports,
is from a middle or upper class background, is an
extrovert, has above-average intelligence and a caustic
sense of humor.
While no specific violence gene has yet been isolated,
there is ample evidence to suggest that violent
tendencies are inherited. Researcher D.C. Rowe
posits that some individuals have a genotype that
disposes them to antisocial behavior.11 These individuals
are characterized by a deficit of social emotions
which include love, shame, guilt, empathy and
remorse. They are keen predictors of other people’s
behavior. Unbridled by emotions, they rely solely
on actuarial data to predict outcomes, never resorting
to feelings or hunches.12 They focus on shortterm
outcomes without taking into account the emotional
reactions of those with whom they are dealing.
Thus they may come across as cold, impersonal
and manipulative.
As previously mentioned, the natural killer is most
likely not a first-born son. Later sons are generally
more aggressive and have less fear or anxiety in
dangerous situations. An Israeli Defense Force
study of its officers from 1961 to 1966 showed that
“first borns” were more anxious than “later borns”
and that they generally sought less dangerous positions
in the military. Later borns were more likely
to volunteer for combat and had a better chance of
encountering terrorists on patrols.13 A study of Korean
War fighter plane aces found that first borns
engaged the enemy less and were more anxious
about flying.14 Family position also seems to relate
to assassins. Almost all American assassins have
been later sons—John Wilkes Booth, Charles Giteau
and Lee Harvey Oswald, to name three.15 Later
borns, by virtue of being routinely dominated by
their siblings, ultimately feel less fear during stressful
situations. They also feel the need to prove their
worth over their siblings and more quickly accept
dangerous challenges.
A natural killer has been a fighter for much of
his life. Frequent fighting as a child does not mean
the individual was a bully. Rather, he chose to respond
to stressful situations with aggression.16
Arthur J. Dollard concluded that aggression is the
result of frustration and this is a normal human reaction.
17 The sociopath, also referred to as the
undercontrolled aggressive personality type, has low
internal controls against violence and will resort to
aggressive behavior unless constrained by rigid external
controls. Such a person can be conditioned
to not respond to frustration with external aggression.
18 Thus, if frustrated by a Drill Sergeant’s control,
the undercontrolled personality type will refrain
from direct aggression and look for another target for
his aggression. The military provides ample displacement
outlets for this aggression in the form of physical
training, field maneuvers and weapons ranges. It is the
perfect environment for a sociopath to excel.
The natural killer is an aggressive athlete whose
physical makeup allows him to excel at contact
sports. Combative sports provide long-term training
in aggression while acting as a short-term catharsis
or safety valve for aggressive individuals.19 An Armyfunded
study of Korean War veterans discerned differences
in the characteristics of fighters—those
who took aggressive action in combat—versus
nonfighters—those who were hysterical or nonre-
There are common traits that are indicative
of natural killers. While the collection of these
traits is not absolutely deterministic of a killer,
it is a good framework for identifying those who
may have this propensity. In general, the
natural killer found in the US Army lacks social
emotions, is a later son (not first-born), got into
frequent fights as a child, enjoys contact sports,
is from a middle or upper class background, is
an extrovert, has above-average intelligence
and a caustic sense of humor.
MILITARY REVIEW l May-June 1999 63
sponsive in combat. This study, conducted by the
Human Resources Research Office (HumRRO), concluded
that the fighters had been more active in contact
sports such as football, boxing or hockey. It also
concluded that fighters had a high masculinity factor
or outdoors adventurousness about them. Their
body types were larger; on average they were an inch
taller and eight pounds heavier than the nonfighters.20
They were rugged individuals who had channeled
their aggressions through contact sports.
Another discriminator for identifying natural killers
is their socio-economic background. Natural
killers usually come from a middle or upper class
background. The volunteer military has had the
luxury to pick and choose those who will be allowed
into the service, and we exclude those with criminal
records. Sociopaths follow a “cheater strategy”
to obtain what they want.21 The lack of a social conscience
allows the sociopath to cheat without remorse.
Consequently, those who find themselves
in the economically disadvantaged lower class will
resort to crime unless placed in a highly controlled
environment. In other words, a sociopath from a
depressed economic background will most likely
have a criminal record, and under today’s standards,
he would not be able to enter the military. Thus,
natural killers in the US military will most likely
come from a middle or upper class background.
Sociopaths are generally extroverts. One reason
for this is the inheritance of a nervous system that US Army
There are several considerations for the positioning of natural killers in the unit.
If they are junior enlisted personnel, they should be assigned to a crew-served weapon. This will
provide them with ample firepower and place them in a position to motivate others. They will
naturally seek this position out anyway. If the natural killer is a noncommissioned officer or
officer, assign him to a leadership position where he will supervise trigger pullers and will
have a weapon system at his disposal. Here they will lead by example, killing the enemy
and motivating others to do so as well.
Soldiers of the 193d Infantry
Brigade prepare to return fire
during Operation Just Cause,
December 1990.
64 May -June 1999 l MILITARY REVIEW
is relatively insensitive to low levels of stimulation.
Individuals with this physiotype tend to be extroverted.
22 They also have lower than average levels
of adrenaline and seek experiences to heighten this.
Extroverts and sociopaths are less affected by threats
of pain or punishment, and they have greater tolerance
of actual pain or punishment. Both sociopaths and extroverts
will approach a situation that most people
will avoid.23 These factors were confirmed by the
HumRRO study conclusion that fighters were extroverted,
spontaneous and relatively free from anxiety.24
The natural killer has above-average intelligence.
Like sociopaths with no economic resources, those
without above-average intelligence end up in jail.
Therefore, sociopaths in our military are usually intelligent.
The HumRRO study found that the intelligence
quotient (IQ) of fighters was, on average,
13 points higher than nonfighters’. The study subjects
were all infantrymen and the mean group IQ
was only 85, 15 points below the national average
of 100. This indicated that less intelligent men were
sent forward to fight, but within that group, the more
intelligent ones were better fighters.25
Additionally, the natural killer has a caustic sense
of humor that relies on sharp wit and biting sarcasm.
26 Such hostile humor acts as a tension-discharger,
a relief valve. While we normally associate
humor with friendly behavior, laughter itself is
a primarily aggressive behavior. Laughter is usually
directed at someone and is infectious, with the
unspoken agreement being to “join in or not be part
of the group.”27 With aggression as the underlying
theme, the natural killer enjoys humor.
Potential natural killers can be identified through
long-term observation testing. Supervisors can look for
natural killer traits in their soldiers. Over time, they will
develop a close enough relationship with their soldiers
to be able to distinguish those who match most of the
characteristics of killers. Personality-type testing
may also identify natural killers. One such test already
in use by the military is the Myers-Briggs personalitytype
test. Considering the characteristics discussed
above, the natural killer would most likely be an ESTP
(extroverted, sensory, thinking, perceiving) personality
type on this test. ESTPs are outgoing, highly
adaptive, deal in facts, sensory oriented, excel at
sports, learn through life experience, prefer action
to conversation and are tough in harsh situations.28
Matching the ESTP personality type to intelligent,
caustic, later sons will help identify potential natural
killers. The ESTP personality type, coupled with
the other associated traits, is not an absolute determinant
of a natural killer or a sociopath, but it provides
a good baseline. Personality-type testing at
initial entry could identify and help place natural
killers where they can best employ their talent—in
infantry, armor and special operations units.
Cry Havoc
The individual soldier does make a difference on
the killing fields. The natural killer is a vital asset
to a unit because he is a killing machine that will
turn the tide of battle when the chips are down.
During World War II, 40 percent of the US Army
Air Forces’ air-to-air killing was done by 1 percent
of its pilots.29 Marshall’s work and the HumRRO
study both found that a small percentage of soldiers
did most of the fighting. It is not enough to rely on
conditioning to produce killers—genetics and childhood
environment have already molded them.
Natural killers bring some obvious advantages to
a unit. They will personally kill the enemy in
droves. They are natural leaders who will motivate
other soldiers to kill. They are also fiercely competitive
and will aggressively pursue victory. In a
battle of attrition, the natural killer can singlehandedly
tip the scales. However, there are drawbacks
to natural killers in a unit too. Their highly
aggressive nature may act as a catalyst for violence
in tenuous situations such as peacekeeping (PK) operations.
This is not to say that they will create
atrocities, which are generally initiated by overcontrolled
personality types in second-in-command
positions, not by undercontrolled personality types.30
Atrocities are the result of the release of pent-up
hostilities—not a characteristic of sociopaths who
live for the moment. Natural killers may participate
in atrocities but they will not initiate them. This
same “live-for-the-moment” attitude makes the
peacetime routine difficult for killers. The sociopath
craves stimulation that the peacetime Army
often does not provide. Marshall concluded that
many of the best fighters spent significant amounts
of time in the stockade—“They could fight like hell
Natural killers bring some obvious
advantages to a unit. They will personally kill
the enemy in droves. They are natural leaders
who will motivate other soldiers to kill. They are
also fiercely competitive and will aggressively
pursue victory. . . . However, there are drawbacks
to natural killers in a unit too. Their
highly aggressive nature may act as a catalyst for
violence in tenuous situations such as peacekeeping
operations.
MILITARY REVIEW l May-June 1999 65
but they couldn’t soldier.”31 Consequently, many of
these individuals seek out fast-paced specialty units
such as Airborne, Ranger or Special Forces units.32
The natural killer will become bored in a regular unit
and may seek the stimuli of sports, fighting or drugs.
Natural killers are motivated by competition and excitement,
not a sense of sacrifice—they are not the kind
of soldiers who will leap on a grenade to protect others.
Another characteristic of the natural killer is to
usurp authority in a crisis to turn the tide of battle.
Marshall wrote of a sergeant whose actions had carried
the battle and yet he had not been recommended
for a decoration. When his company commander
was asked why, he replied, “When the fighting
started he practically took the company away from
me. He was leading and the men were obeying him.
You can’t decorate a man who’ll do that to you.”33
There are several considerations for the positioning
of natural killers in the unit. If they are junior
enlisted personnel, they should be assigned to a
crew-served weapon. This will provide them with
ample firepower and place them in a position to
motivate others. They will naturally seek this position
out anyway. If the natural killer is a noncommissioned
officer or officer, assign him to a leadership
position where he will supervise trigger pullers
and will have a weapon system at his disposal. Here
they will lead by example, killing the enemy and
motivating others to do so as well.
Natural killers may be spread out in the unit or
concentrated, depending on the tactical situation.
The typical officer cannot single-handedly lead an
entire company in combat.34 By spreading out those
who will carry the day you increase your chances
for success in battle. Wherever they are placed in a unit
though, they may take over command based upon the
situation and the leaders around them. This may be
desirable depending upon the quality and number
of your other leaders. You can “backstop” leaders
of unproved ability with natural killers. If there is
a well-defined decisive point of the battle, the commander
may choose to place natural killers at that
point. They will provide that final measure of resolve
in the assault or become the defense linchpin.
Since natural killers are motivated by competition
and excitement, they should not be placed in a reserve
position, where they would have to patiently
wait, then hurl themselves into the breach on command.
Quick to take charge, they will move to the sound of
the guns unless tightly controlled. In PK operations,
keep them in positions where they will not habitually
deal with potential combatants. This will minimize the
risk of escalating the tension into violence. Likewise,
during peacetime operations, keep them active
in exercises, schools or in sports. They will seek
out these activities themselves to stay stimulated.
Too often we find out about the lethality of an
individual soldier after the fact, when he has saved
the unit and been nominated for a valorous award.
If you knew before hand who was likely to rise up
and save the day, you could place these soldiers at
the battle’s decisive point and enhance your chances
of success. Natural killers are out there in your unit
right now—find them and use them wisely. MR
Major David S. Pierson is the 165th Military Intelligence Battalion XO, Darmstadt, Germany.
He received a B.A. from the University of Georgia and an M.A. from Webster University,
and he is a graduate of the US Army Command and General Staff College (CGSC). He has
held a variety of command and staff positions in the Continental United States and Germany,
including G2 operations officer, V Corps, Heidelberg, Germany; chief, collection management,
United States Transportation Command, Scott Air Force Base, Illinois; and commander,
A Company, 124th Military Intelligence Battalion, Fort Stewart, Georgia.
NOTES
1. S.L.A. Marshall, Men Against Fire: The Problem of Battle Command in Future
War (Washington DC: Infantry Journal Press, 1947, reprint Gloucester, MA:
Peter Smith, 1978), 79.
2. Ibid., 56-57.
3. Dave Grossman, On Killing: The Psychological Cost of Learning to Kill in
War and Society (Boston, MA: Little, Brown, and Company, 1996), 177-85.
4. Marshall, 9.
5. Grossman, 35.
6. Mark Baker, Nam (New York: William Morrow and Company, 1981), 161-62.
7. Marshall, 58-59.
8. Swank and Marchand, in On Killing, 180.
9. Ralph Serin, “Can Criminal Psychopaths be Identified?” FORUM 1989, Volume
1, Number 2.
10. C.C. Strauss and B.B. Lahey in: The Sociobiology of Sociopathy: An Integrated
Evolutionary Model, Linda Mealey, unedited penultimate draft of an article
accepted for publication (Copyright 1994: Cambridge University Press).
11. D.C. Rowe, “Inherited dispositions toward learning delinquent and criminal
behavior: New evidence,” in Crime in biological, social, and moral contexts, ed.
L. Ellis and H. Hoffman (Praeger Publications, November 1990), 122.
12. Linda Mealey, in The Sociobiology of Sociopathy, 3.
13. Peter Watson, War on the Mind: The Military Uses and Abuses of Psychology
(New York: Basic Books Inc., 1978), 51.
14. E.P. Torrence, The development of preliminary life-experience inventory for
the study of fight-interceptor combat effectiveness, Research Bulletin AFPTRCTR-
54-89, Lackland Air Force Base, San Antonio, TX, December 1954.
15. Irving D. Harris, Violence: Perspectives on Murder and Aggression (San
Francisco: Jossey-Bass Publishers), ed. Irwin L. Kutash, Samuel B. Kutash and
Louis B. Schlesinger, 203.
16. Grossman, 182.
17. J. Dollard et al., Frustration and Aggression (New Haven, CT: Yale University
Press, 1939).
18. Edwin I. Magargee and Jack E. Hokanson, The Dynamics of Aggression: Individual,
Group and International Analyses (New York: Harper & Row, 1970), 111.
19. Irenaus Eibl-Eibesfeldt, The Biology of Peace and War: Men, Animals, and
Aggression (New York: The Viking Press, 1979), translated from German by Eric
Mosbacher (R. Piper & Co., Munich), 110-11.
20. Watson, 49-50.
21. Mealey, 33.
22. Ibid., 17.
23. Ibid., 14.
24. Watson, 49.
25. Ibid.
26. Ibid.
27. Eibl-Eibesfeldt, 90.
28. Isabel Briggs Myers, Gifts Differing (Palo Alto, CA: Consulting Psychologists
Press, 1980), 101-104.
29. Grossman, 181.
30. Watson, 245.
31. Marshall, 60-61.
32. Grossman, 181.
33. Marshall, 62.
34. Ibid.
OPERATIONAL LEADERSHIP
