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Criminology 2330
Biology and
Criminal Behaviour
A Basic Issue
• Is criminal behavior caused or is it
the product of free will?
• If caused, are criminals
biologically different than noncriminals, or is it their social
experiences that matter most?
• Lombroso (1835-1909)
–Father of Criminology
–Atavism
–Hypothesized bodily features
predict criminal behaviour
–Research in Italian prisons
• Charles Buckman Goring, at about the
turn of the twentieth century, concluded in
a well-controlled statistical study of
Lombroso's thesis of atavism that “the
whole fabric of Lombrosian doctrine,
judged by the standards of science, is
fundamentally unsound.”
• LOMBROSO’S Legacy is the
application of scientific approach to
causes of crime
Genetics and Criminal Behaviour
• What are genes?
Units of hereditary DNA
• What is heritability?
– Differences due to genes compared to environmental
influences.
– eye colour, height, diseases, mental disorders, IQ
Common Misconceptions
•
A single gene exists for criminal behaviour.
•
Genetic influences preclude possibility of treatment.
•
Genetics cannot influence something that is socially
constructed.
•
Fluctuating crime rates preclude a genetic influence.
Crime Gene
disorders are polygenic in nature
– Influenced by many genes & cannot be traced to single gene
Exception:
Chromosomal Abnormalities
XYY - “Supermale Syndrome”
(tall, intellectually slow, and violent)
~ Over-represented in male inmates
MAOA + risk for impulsivity
& violence
• team of researchers uncovered
neurobiological factors that contribute
significantly to violence in humans (2009)
• X- chromosome linked monoamine-oxidase
• shown to be associated with impulsive aggression
in humans and animals
• low activity MAOA enzyme group displayed
higher aggression when paired with poor
childhood environment when provocation is high
Twin Studies
• Concordance Rate
– degree which related pairs both show a particular
behaviour or condition.
• If genetic component: then
– MZ (who are genetically identical) will have higher
concordance rates than DZ
Twin Studies
• This is regularly seen that identical twins have
higher concordance rates for antisocial behaviors
than fraternal twins, even when reared apart
• Study children separated from biological
parents and raised by adoptive parents
– Greater criminality among children with criminal
biological parents (vs. children with non-criminal
biological parents) suggests a genetic influence
Adoption Studies
• Adoption data allow us to examine the effects of environment on
human development.
• Typical adoption studies measure the traits behaviors of the
offspring and of the adopted and biological parents.
• These studies indicate that adopted children behave more like their
biological parents than their adoptive parents.
• Evidence also shows important interaction effects between having
criminal biological parents and being adopted into a criminal
household. Again, demonstrates the effects of environment on
genetic expression.
Adoption Studies
Danish Adoption Study
(Mednick et al., 1984, 1987)
14,427 children adopted 1924-1947
Reviewed conviction records of biological
parents, adoptive parents, and adoptee
• Large scale study.
• Concordance rate for criminality was higher
for biological parents than adoptive parents.
If either biological parent had been convicted
for a crime, the risk of criminality increased
significantly for the adoptive child
• No relationship in regards to the type of crimes
committed between biological children and
biological parents
Summary: Concordance Rates
• Clear & consistent evidence showing a genetic link to
various human traits and behaviors.
• All sources of data (family studies, twin studies, and
adoption studies) converge on this conclusion indicating
that genetics may contribute moderately to becoming
criminal, but environment is also important.
• The evidence comes from various countries & from
independent researchers.
• Biological predisposition that environmental factors
may either inhibit or facilitate.
Neuroanatomy
• Different brain regions may predispose certain
individuals to commit antisocial acts
• Differences might be from Traumatic Brain Injury
(TBI) or may reflect variations controlled by
genes.
Case study: Chris Benoit
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Professional wrestler
well-known for
appearances in WWE
In June, 2007 he is believed
to have hung himself after
killing his wife and 7-yearold son.
Post-mortem examination of
Benoit’s brain revealed
extensive damage
a neurologist concluded
the damage may have
produced a form of
dementia that brought
about bizarre changes in
Benoit’s behaviour
McKeown & Karp, 2008
http://img.photobucket.com/albums/v452/bbsrock/flickr.jpg
Benoit may have been suffering from repeated, untreated
concussions throughout his wrestling career, ultimately leading
to an unstable mental state. He "was one of the only guys who
would take a chair shot to the back of the head...which is
stupid.” Tests were conducted on Benoit's brain by Julian Bailes,
the head of neurosurgery at West Virginia University, and results
showed that "Benoit's brain was so severely damaged it
resembled the brain of an 85-year-old Alzheimer's patient.”
Tests conducted on Benoit's brain tissue have revealed he did in
fact suffer from severe chronic traumatic encephalopathy (CTE),
and had brain damage in all four lobes of the brain and brain
stem. These tests revealed similar results to the study of the
brains of four retired NFL players who have suffered multiple
concussions, sank into depression and harmed themselves or
others. Repeated concussions can lead to dementia, which can
contribute to severe behavioral problems.
Major Parts of the Brain of Concern to Criminologists
Frontal Lobe
- Higher order functions: reasoning, planning, judgment, patience, abstract
thought, moral reasoning, aggression regulation
Temporal Lobe
- Amygdala: emotional and fear situations
- Hippocampus: memory, learning, emotion regulation
Parietal Lobe
Sensory information related to movement and space
Cingulated gyrus
Surrounds the Corpus Callosum (joins right and left hemispheres)
Limbic system includes amygdala, hippocampus and cingulated gyrus
Emotional regulation, autonomic expression of emotions
(basic drives, fight or flight response)
MANY BRAIN STRUCTURES CAN IMPACT AGGRESSION!
Key Points
Frontal Lobe – Inhibition and Self control
Temporal Lobe – Feeding, Fleeing, Fighting, Fornicating
Frontal Lobotomy
• In 1935, researchers in U.S reported that damaging frontal
lobes and a nearby region of the brain called the prefrontal
cortex could pacify a previously aggressive chimpanzee
• consists of cutting the connections to and from the
prefrontal cortex -- anterior part of the frontal lobes of
brain
• Carried out mostly in 1940s to mid 1950s to curb
aggression
• "ice-pick lobotomy" -- tap an ice pick through the thin
bone on the roof of eye sockets; with the ice pick in the
brain, sweep it back and forth to cut the frontal lobe's
connections to the rest of the brain
– Done to thousands of psychiatric patients
Phineas Gage
Sept. 13th, 1848:
– Gage, a railway worker, had
a tamping iron iron rod (37
by 1.25 ) explode through
his left cheek and up
through his frontal lobe.
Effects of brain damage
– Gage survived but
demonstrated drastic
changes in personality and
cognitive functioning.
– -hostility, verbal aggression
Frontal Lobe Damage
Frontal lobe deficits facilitating violence:
1. Deficits in inhibitory control
• No stop & Think
2. Deficits in planning (Impulsivity)
• Decreased capacity to self-correct, learn, and think
flexibly
3. Rigidity (learning deficits)
• Continuing a response after it is no longer appropriate
4. Interpersonal inappropriateness
• Unable to read social cues
Incidence of Acquired Brain Injury
• 50,000 Canadians sustain a traumatic brain
injury every year
• majority are young men b/w ages of 15-30
• males experience brain injury twice as often as
females
• More than half people w/ brain injuries are under
age of 20
• highest incidence in the 15 to 19 age range
Brain Injury Association Network
Traumatic Brain Injury
• juvenile & adult violent offenders characterized by hx of significant
head injury likely be caused by accidents or early child abuse (95%
of infant head injuries due to child abuse)
• 50% of offenders suffered a head injury as compared with 5-15% of
non-offenders (Sarapata et al., 1998).
• Head injured show raised levels of antisocial & violent
• Does impulsivity cause head injuries or does head injuries cause
impulsivity???
Left Hemisphere Dysfunction
Temporal-Limbic Damage
The Amygdala
-unprovoked or
-key roles in emotions, fear
exaggerated anger,
responses and pleasure.
memory, and intellectual -stimulation in monkeys
impairment
increases aggression.
-Auditory or visual
-stimulation in humans
hallucinations
results in heightened
-Delusions
emotionality with fear
and rage.
-Receptive Language
Impairment
Charles Joseph
Whitman
Died Age 25
As a student at the University of Texas at Austin,
killed 14 people and wounded 32 others during a
shooting rampage on and around the university's
campus. The tower massacre happened shortly
after Whitman murdered his wife and mother at
their homes. He was shot and killed by Austin
Police Officers.
Charles Whitman grew up in an upper-middle class
family headed by a father who owned a successful
plumbing contract business in Florida. Whitman
excelled at academics and was well liked by his
peers and neighbors. There were underlying
dysfunctional issues within the family that
escalated in 1966, when the mother left the father
and moved to Texas. The elder Whitman was an
authoritarian who provided for his family, but
demanded near perfection from all of them. He was
also known to become physically and emotionally
abusive.
His frustrations were complicated by a dysfunctional
family, abuse of amphetamines, and health issues
including headaches that he reported in one of his
final notes as "tremendous." A cancerous brain
tumor, was discovered during autopsy that experts
claimed may have conceivably played a role in
causing his actions.
It was revealed during the autopsy that Whitman had
a tumor in the hypothalamus region of his brain.
Some have theorized that this may have been
pressed against the nearby amygdala, which can
have an effect on flight responses. This has led some
neurologists to speculate that his medical condition
was in some way responsible for the attacks, as well
as his personal and social frames of reference.
http://www.youtube.com/watch?v=hA4M04prVK8
Autonomic Arousal Theory of Crime
Low levels of arousal, predisposes a person to
crime
Creates fearlessness
Encourages thrill seeking behaviors (antisocial
stimulation)
As a result, they have low levels of anxiety and
fear
Conversely, high levels of autonomic arousal
encourage positive behaviors due to the fear of
disappointment and punishment
Neurochemistry & Antisocial Behaviour
• Neurotransmitters (chemical messengers)
– convey “information” in the form of an electrically
charged signal from neuron to neuron & from brain
structure to brain structure
Norepinephrine (ne)
• “Fight & flight” response; related to arousal,
mood, & behavioural activation
• NE & Violence
– indirect relationship to aggression
– e.g., Amphetamine use & aggression (releases
norepinephrine, dopamine and serotonin but
then creates a state of depletion)
• NE activity levels are impacted by medications
used in treatment of violence
(e.g. clozapine or other antipsychotics)
Serotonin
• involved in many functions including mood, arousal &
impulse regulation
• Important in its association with aggression
• Lots of serotonin in the frontal cortex = executive
functioning, self-regulation
Low serotonin = disinhibition of aggression upon provocation
low serotonin levels & aggressiveness (examples)
• negative correlation b/w serotonin level & measures
of aggression in psychiatric patients
• low serotonin reported in children w/ disruptive
behaviour & low levels have been linked to crime
• Low serotonin levels in people who completed
suicide
Serotonin & alcoholism
• Low levels may contribute to inability to inhibit
behaviour and impulsive urges when drinking.
• Alcohol lowers serotonin more in individuals who
already have deficiencies in serotonin.
• When drinking, these individuals more likely to
feel hostile & negative.
Dopamine
• Dopamine = pleasure center
• Rewards increase levels of Dopamine
• Porn addictions??
Biochemistry – Hormones:
Testosterone
• voluntary castration allowed in Federal Republic of
Germany (since 1970)
• follow-up of 99 castrated sex offenders & 35 noncastrated sex offenders for, on average, 11 years after
release
• recidivism rate over an average of 11 years post-release
was 3% in castrated offenders compared to 46% in noncastrated offenders
Testosterone: Women
• Compared levels of testosterone among 3 groups
of female inmates
1) violent crime (homicide, assault, or robbery)
2) non-violent (theft, forgery, drug trafficking)
3) defensive violence (homicide or assault
against someone who had abused the inmate)
• Inmates involved in violent crimes had higher
testosterone values than those in other two
groups
“Other” Biological Factors
• PMS - in one sample of 156 convicted women, 46%
of crimes had occurred either 4 days prior to or after
menstruation; a figure higher than expected by
chance (29%).
• Hypoglycemia (“twinkee defence”)
A small note about sexual
offenders
• Research by James Cantor
• Left handedness – pedophiles
• Significant difference between IQ for
pedophiles and those who prefer adult
partners (IQ below 90 vs IQ average 100) –
Cantor (2004)
• Pedophiles more head injuries BEFORE age 13
than those who prefer adult partners
• Pedophiles are significantly SHORTER (by 2
cm)
More about pedophiles…
• You can differentiate pedophiles with an MRI
in GROUPS
• With an fMRI you can see differences on how
pedophiles respond to children vs how
normals respond to adults
• http://individual.utoronto.ca/james_cantor
Other biological aspects
• Food and nutrition!
- early malnutrition at age 3 can impact brain
development and lead to antisocial behaviors
later in life
- The resulting brain impairments resulting from
malnutrition impact executive functioning
- Good nutrition can reduce recidivism
• Neurotoxins (e.g. lead)
• Birth complications