Into the mind of a
serial killer…
Jeffrey Dahmer
Born 1960
Looked for dead animals to dissect as an early teen
Alcoholic by high school graduation
Discharged from army for alcoholism
Arrested for indecent exposure in front of boys
Arrested for molesting a 13-year old boy - paroled
Murdered 17 men and boys between 1978-1991
Involved rape, torture, dismemberment, necrophilia and cannibalism
Killed in prison 1994
Guilty or Not Guilty?
What’s your verdict?
Who determines admissibility of
scientific evidence?
Expert witness / forensic scientist
1923 - Frye Standard
• says scientific evidence must be presented by “expert witness” &
must have “general acceptance”
1993 - Daubert Ruling
• says that the judge determines validity and reliability of scientific
analyses or techniques used to identify evidence
• Judge must use scientific methods as guidelines
– Testability, standard techniques, peer review and acceptance
within the scientific community
Many twin studies show that if one
identical twin demonstrates antisocial
and aggressive behavior the other one
will also - More so than in fraternal twins.
(growing up together or apart)
What does this mean?
…genes must play a role
Many studies show links between
aggression and/or antisocial behavior
contributing to violent crime and
Imbalances of neurotransmitters
& hormones:
Serotonin, catecholamine ,
glutamine/gaba, testosterone
The brain’s aggressive,
impulsive capacity to display
violence may increase if…
– Activity of the lower, more
primitive brain stem is
increased or stimulated.
-or– Moderating activity of the
cortical and limbic areas is
Not everyone that is
aggressive, impulsive, or
even violent….
is a
serial killer !
Were these people insane?
• Henry Lee Lucas blamed his upbringing.
• Jeffrey Dahmer said he was born with a part missing.
• Ted Bundy claimed that pornography made him do it.
• Herbert Mullin (Santa Cruz killer) blamed the voices in
his head that told him it was time to “sing the die song”.
• Carl Panzram said the prison turned him into a
• Bobby Joe Long said a motorcycle accident made him
hypersexual and eventually a serial lust killer.
• John Wayne Gacy said the victims deserved to die.
Are they insane?
1. Psychotic – Legally insane – loss of contact with reality
May hear voices, hallucinate, cannot tell right from wrong, anxious, confused
Competent to stand trial? Accountable for actions?
1% of criminals
2. Psychopath / Sociopath / (APD) Antisocial
Personality Disorder –
NOT legally insane (but, moral insanity?)
Can differentiate right from wrong, just don’t care
Competent to stand trial? Accountable for actions?
Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) - standard classification of mental
disorders - used by clinicians and researchers
Psychopathy Statistics
• 0.5 – 1 % of people are psychopaths
• Many, but not all psychopaths commit violent
• 15% – 35% of U.S. prisoners are psychopaths
• Psychopathy is one of the strongest predictors of
persistent and severe criminal conduct
• Psychopaths offend earlier, more frequently and
more violently than non-psychopathic criminals
• They are 4-8 times more likely to commit new
crimes on release.
• 40% of rapists are phychopaths
How is a psychopath diagnosed?
Hare’s Psychopathy Checklist (PCL-R)
Twenty traits are assessed. 0-2 points each
A PCL-R score between 0 – 40
Average non-psychopathic person = approx 4
Psychopath = 30 or higher
40 = prototypical psychopath
– There is direct correlation between this score and
likeliness to violate parole.
Should this assessment be applicable to parole hearings?
A disorder consisting of a range of interpersonal,
affective and behavioral features - 4 factors:
Medical Advancement
Brain Imaging of violent/criminal offenders
– Static Imaging Techniques
• CT scans: X-ray from different angles = 3-D
• MRI’s: measures different regions of H density
– Dynamic Brain Imaging – show change in activity
• functional fMRI’s: blood flow
• PET positron emission tomography: radioactive O
• Optical Tomography: near infra-red spectroscopy
fMRI study:
Those with higher psychopathy scores (all 4 factors), showed reduced activity in amydala.
Reduced activity in the posterior cingulate, medial prefrontal cortex and the angular gyrus
corresponded to those with higher interpersonal psychopathic factors.
Abnormal temporal and prefrontal cortical
gray matter thinning in psychopaths
a. Psycopath and control - cortical thinning
b. Correlation between Affective facet & cortical thinning
Negative associations between Affective facet scores
and cortical thickness in anterior and medial temporal
regions. Consistent with fMRI studies.
Link to emotional deficit, especially inability to process
negative or fearful facial expression.
Researches have argued which dysfunction is central to
the emotional and moral deficits of a psychopath.
– Amygdala – fear and emotional response
– OFC (orbitofrontal cortex) – crucial to learning
behaviors, associating with
Amygdala or OFC?
The Amygdala & OFC are connected by
fibers of the Uncinate fasciculus (UF).
- white matter connections
A virtual
dissection of
the major
the amygdala
and the
Psychopaths –
reduced tracts
in right
Uncinate Tract
The moral-neural circuit
Self-referential thinking, emotional
perspective taking, recalling emotional
experiences, integrating emotion into
social cognition
moral decision making, responds to
cues indicating distress in others, fear
A dysfunction in any one of these regions, disrupts this processing circuit,
resulting in a psychopathic personality. Different severity of facets of disorder?
Other associations…
• Decrease in posterior hippocampal
• An exaggerated structural hippocampal
• An increase in callosal white matter
Crime: Nature or Nurture?
• Most scientists agree that there is some genetic
predisposition to the development of many brain
dysfunctions that cause criminal behaviors.
Irregular production of hormones or
neurotransmitters, etc
• Most scientists agree that environment affects the
developmental of brain dysfunctions that influence
these behaviors.
Birth complications, nutrition, lack of physical
touch, abuse, neglect, social environment, alcohol,
injury, nutrition, heavy metals, infections
• The precise contribution of these two components is
currently being researched.
Legitimate defense?
• If you were the judge, would you deem this
evidence admissible? (according to the
scientific evidence shown) Why?
• If you were a member of the jury assigned
to these hearings, would you return a
verdict of guilty or not guilty? Why?
• If you convicted him, what would your
sentence be? Imprisonment? Death?
Medical help?
Psychopathy – Essentially an emotional disability
caused by one of many possible dysfunctions in the brain.
• Senseless to ignore psychopaths when they
statistically pose such a threat
– Should we test at early ages?
• Most psychopaths show signs by the age of 5.
• Are these assessments in juveniles reliable, as in adults?
– Lock up or treat people with high psychopathic score predisposition for crime - for the greater good?
• Treatment has not worked, so far, only enhanced behavior.
• Affect of research on criminal justice system
– Defense / responsibility (disorder) – sentencing
– Assessing danger or reoffending – parole, probation
Prevention / Treatment / Research
• Protective environmental influences for those with
genetic predispositions / those who show early signs
• New treatment: Decompression Therapy
– Intensive 1-on-1 therapy for juvenile offenders with psychopathic
tendencies - successful so far
– Much less expensive than keeping someone in jail
• Billions spent on depression – less than a million on
treatments for psychopathy
• Multimillion-dollar project launched by NIMH (mental
health) & NIDA (drug abuse) to gather genetic info, brain
images and case histories from 1000 psychopaths,
portable scanners in prisons

Psychopaths - Wilbur World of Science