Psychology of Serial
Killers
“The Mask of Sanity”
A serial killer is someone who commits three
or more murders over an extended period of
time with cooling-off periods in between. In
between their crimes, they appear to be quite
normal, a state which has been called call the
"mask of sanity."
Types of Multiple Killers
Mass Spree
# of victims
# of events
# of locations
Cooling-off period
4+
1
1
no
2+
1
2+
no
Serial
3+
3+
3+
yes
Serial Killer Frequency
 Hickey (2002)
 337 males and 62 females in U.S. from 18001995
 158 males and 29 females in U.S. from 19751995
 Gorby (2000)
 300 international serial killers from 1800-1995
 Radford Data Base
 1300 serial killers
 U.S. and International
Motivation
• motivated by a variety of psychological urges
• primarily power and sexual compulsion
• often have feelings of inadequacy and
worthlessness
• often suffer humiliation and abuse in childhood
• seek a sense of potency and/or social revenge
• that their actions terrify entire communities and
often baffle police adds to their sense of power
Prevalence
 According to the FBI,
there are approximately
thirty-five active serial
killers in the United
States.
 John Wayne Gacy –
convicted of the rape
and murder of 33 young
boys and buried them in
the crawl space under
his house
What makes serial killers
tick?
“It was an urge. . . . . A
strong urge, and the
longer I let it go the
stronger it got, to where I
was taking risks to go
out and kill people--risks
that normally, according
to my little rules of
operation, I wouldn't take
because they could lead
to arrest."
-- Edmund Kemper
General Serial Killer
Profile
 Male
 Kraemer, Lord & Heilbrun (2004) study of 157 serial
killers: 96%
 White
 80.2% of all serial killers 73% of male serial killers
 93% of female serial killers
 Average intelligence
 107 IQ
 n = 71
General Serial Killer Profile Childhood
 Birth Order




Only child
Oldest child
Middle born
Youngest
16%
33%
28%
23%
 Adopted
 Adopted
14%
 Birth parent(s) 79%
 Other
7%
General Serial Killer Profile Childhood
 Unstable home (37%)
 Absence of loving and nurturing
relationship
 Physical ailments and disabilities
 Head injuries
 Triad
Effects of the Family
Child Abuse
Comparison of Serial Killers to the General Population
(Mitchell & Aamodt, 2005)
Type of Abuse
General
Population
Serial Killers
Physical
6%
36%
Sexual
3%
26%
Psychological
2%
50%
Neglect
18%
18%
Other
6%
Not applicable
No Abuse
Reported
70%
32%
Born Bad?
 As a child, Ed Kemper was beheading
his sisters dolls and once remarked that
he wanted to kiss his second grade
teacher but he’d “have to kill her first.”
 Albert DeSalvo was sold of as a slave by
his alcoholic father.
 If there is no parent-child bond a child
may grow isolated.
The Boston Strangler
“Instead of developing
positive traits of trust,
security, and autonomy,
child development
becomes dependent on
fantasy life and its
dominant themes,
rather than on social
interaction." - Special
Agent Robert Ressler
The Father
 Many serial killers have sadistic disciplinarian
fathers
 DeSalvo’s father would bring home
prostitutes and beat his mother
 Sold his children off as slaves
 Gacy’s father was a violent alcoholic who told
his son he was a “sissy” and “queer”
 Shot the boy’s beloved dog to teach him a
lesson
Gary Heidnik
 At 3 years old father
hung him by his feet out
of a 3rd story window for
not cleaning room
properly
 Diagnosed as having a
schizoid personality
disorder
 Enslaved and tortured 6
women and murdered 2
The Mother
 For many serial killers it all starts or ends with
their mother
 Henry Lee Lucas launched his career by
murdering his mother
 Ed Kemper ended his by killing his mother
 Ed Gein’s mother was a religious fanatic who
believed women were vessels of sin and
disease
 Heidnik’s mother committed suicide when he
was 23
Henry Lee Lucas
3 years old
 Mother forced him to watch her have sex with
strangers
 Spent 3 days in a coma after mother hit him
with a plank of wood
7 years old
 Mother made him go to school dressed like a
girl until he was in the second grade
 She beat him when his teacher gave him a pair
of shoes
10 Years old
 Mother shoots a mule he was given as a
present by a family friend
Murdered mother at age 24. Convicted of 11
murders. Linked with 213.
Adoption
 An unusually high percentage of serial killers are
adopted raising the question of nature versus nurture
 May undermine sense of identity during a fragile
youth
 Makes the child prone to fantasizing
 Creates a sense of rejection
 David Berkowitz was devastated when his biological
mother wanted nothing to do with him
 Ted Bundy’s emotional development stopped when
he was 13 and found out he was illegitimate
“It was like I was hit by a brick wall.”
The MacDonald Triad
Animal Cruelty/Bed Wetting/Pyromania
 Secret compulsion seen as the seeds of greater mayhem
“Violent acts are reinforced, since the murderers either are
able to express rage without experiencing negative
consequences or are impervious to any prohibitions
against these actions. Second, impulsive and erratic
behavior discourages friendships, increasing isolation.
Furthermore, there is no challenge to the offenders' beliefs
that they are entitled to act the way they do.”
– Special Agent Richard Ressler
Animal Cruelty
 Red flag and often seen
as “practice”
 Ed Kemper buried the
family cat alive after it
showed his sister more
attention, dug it up only
to decapitate it
 Dahmer routinely
tortured and mutilated
stray dogs
 Berkowitz tortured his
mother’s parakeet
Bed Wetting
 60% of serial killers
wet their bed postadolescence
 Ken Bianchi
Pyromania
 Often sexually
stimulating for the
arsonist
 Destruction of property
feeds the same perverse
need to destroy a human
being – thrill of
destruction
 See humans as objects
and can easily make the
leap from setting fires to
killing people
Bad Seeds Blossom In Bad
Environments
 Environment alone
cannot explain
deranged behavior
 Yet we do not see
entire families of
serial killers
 Some genetic
tendencies to bad
behavior
 Ted Bundy
Heavy Metals
 Research has indicated that
serial killers have a higher
than normal level of heavy
metals (lead, manganese,
copper) in their systems
 Lowers the level of dopamine
and serotonin which
increases violent behavior
 James Huberty – murder 21
people and injured 19 in a
shooting spree in a
McDonald’s Restaurant in
1984.
 High levels of cadium
Brain Defects
“After I am dead they are
going to open up my
head and find that part of
my brain is black and dry
and dead.”
- Bobby Joe Long who
murdered 10 women in
an 8 month span in 1984
Strange Brains
 Brain defects and injuries have been linked to
violent behavior.
 When the hypothalamus, the temporal lobe,
and/or the limbic brain show damage, it may
account for uncontrollable aggression.
 The hypothalamus regulates the hormonal
system and emotions.
 Physical closeness of sexual and aggressive
centers within the hypothalamus cause
sexual instinct and violence to become
interconnected for lust murderers.
Brain Injury






Leonard Lake
David Berkowitz
Ken Bianchi
John Gacy
Carl Penzram
Albert Fish (pictured)
 54% of confessed serial
killers had suffered some
type of brain trauma
Lust Killers
 Ultimately a quest for power
 Sexual domination represents an
expression of that power
 Drawn to authority figures in
fiction/history
 Fascination with law enforcement
 Often identify with perceived sources of
power
Ted Bundy
“I wanted to be master of
life and death.
Possessing them
physically as one would
possess a potted plant, a
painting, or a Porsche.
Owning, as it were, this
individual.”
 Bundy raped and
murdered at least 37
women.
Organized vs.
Disorganized
 FBI has categorized serial killers into two
different types
 Reflects killer’s emotional and psychological
state
 A significant number of serial killers show
certain aspects of both categories
 Descend from organized to disorganized as
killing continues and need to feed compulsion
grows
Organized
 Highly intelligent and plan crimes methodically
 Kill victims in one place and dispose of them in
another
 Lure victims by appealing to their human nature (e.g.
Bundy’s plaster cast)
 Choose a victim to hunt
 Maintain high degree of control over the crime scene
 Knowledge of forensic sciences which enables them
to cover their track
 Closely follow crimes in the media taking great pride
in their accomplishments
 Usually socially adequate with close friends, lovers,
spouses, and children
Disorganized
 Often of lower intelligence and commit crimes
impulsively
 Will kill when an opportunity presents itself
 Rarely disposes of a body
 Rarely cover tracks, but will evade capture do
to transient nature
 Socially inadequate with few friends and often
have a history of mental problems
Homework
Read pages 93-99.
Read the case study on page 94 entitled Clifford
Olson. Answer questions 1 and 2.
Read the case study on page 95 entitled A Tale
of Two Sociopaths. Answer Recap question
number 3 on page 99.
Based on what you have read and learned, do
you believe the media’s depiction of serial
killers is accurate? Explain your answer.