Transcript The Behavioral Genetics of Predatory Criminal Behavior

Chapter 3: The Behavioral
Genetics of Predatory Criminal
Behavior
John Paul Wright
Kevin M. Beaver
Overview
• The leading criminological theories social learning
theory, strain theory, and self-control theory all
require biological and genetic factors to be valid
• The media frequently reports startling results linking
brain functioning to criminal behavior, or reports new
linkages between specific genes and criminal traits
• This may be why “the biological sciences have made
more progress in our understanding of criminal
behavior in the last 10 years than sociology has
made over the past 50 years” (Robinson, 2004:x)
Overview
• This chapter seeks to demystify the influence genes
have on behavior and serves to introduce the reader to a
“biosocial” understanding or predatory offending
• In particular we provide the reader a brief introduction on
what is known about:
– Predatory offending, about the fundamentals of
human genetics, about the methods used by
behavioral genetics, and about how this information is
used to understand predatory human behavior
The Roots of Predation
• Predation involves an intention to do harm to
another, or at least a willingness to actively seek
out and injure another person
• Even among criminals, predation in criminal
conduct is unusual – only the most serious and
habitual offenders are predatory
• This is not to say that predatory offenders are
not also opportunists or that they do not commit
crimes when under the influence
• The difference is that predatory offenders do not
require or are not driven by these concerns –
predatory offenders are the truly criminal
The Roots of Predation
•
Research findings on the development of serious
criminal conduct have revealed 3 important
findings:
1.
An amazing wealth of data converge to show
that the warning signs for serious predation are
visible in infancy and childhood
1.
Traits related to later criminal conduct are also
visible in infancy and early childhood
2.
Studies into the development of aggression
have found that its onset occurs around the time
when children gain mobility
The Roots of Predation
• Physical aggression is a nearly universal human
capacity, is “normal” early in life, but becomes
more uncommon in children over time
• Perhaps not surprisingly, an early age of onset is
one of the strongest predictors of future adult
predatory offending
• Moreover, virtually every predatory offender has
experienced an early age of onset
A Behavioral Genetic Understanding of
Predatory Offending
• Traditional criminological theories remain silent – largely
because these theories of crime locate the causes of
misconduct in adolescence
• Criminologists would likely point to parental rearing
environments as the putative source variation in young
children’s behaviors
– But would they be correct?
A Behavioral Genetic Understanding of
Predatory Offending
• Behavioral genetics is the field of study that
examines how much variance in any given trait
or behavior is accounted for by genetic and
environmental influences
• At the heart of the field is the estimation of
genetic and environmental influences
• Behavioral geneticists also specify 2 types of
environmental influences:
– Shared environments
– Non-shared environments
A Behavioral Genetic Understanding of
Predatory Offending
• Non-shared environments: are those unique experiences
that make individuals more different than alike
• Shared environments: are thought to make people more
alike
• Findings from hundreds of studies now show that
virtually every human trait and characteristic is
genetically influenced
A Behavioral Genetic Understanding of
Predatory Offending
• For certain characteristics – especially those associated
with predatory offending – genetic influences dominate
• The behavioral genetic studies typically show that
shared environments have little to no effect on their adult
offspring
• The processes that link parenting practices to human
development likely operate through biological
mechanisms
A Brief Note on Human Genetics
• Human-beings inherent 22 pairs of chromosomes
from each parent, plus 1 sex differentiating
chromosome
• DNA is composed of 2 elongated sections bonded
to chemical bases – the now familiar double-helix
• Genes, which are embedded in chromosomes,
are merely stretches of DNA with a known
arrangement of base pairs
A Brief Note on Human Genetics
• Mendelian theory tells us that we inherit 2 copies
of each gene – 1 from the father and the other
from the mother
• Genes play a significant role in serious,
predatory behavior
• Even with multiple copies of some genes, they
are not all turned on or off at one time
A Brief Note on Human Genetics
• The process whereby our genes are activated or
turned off is called genetic imprinting
• Genes come in different varieties – differences in
genes are called alleles
• Allelic variation occurs when mutations, genetic
drift, culture or evolution alters a gene
• Genes with various alleles (a lee os) are referred
to as polymorphic
A Brief Note on Human Genetics
• Understanding the role of genes in complex
human phenotypes is made even more
complicated by the fact that humans do not
always follow Mendelian genetic principles
• Functional human genes appear to follow a
pattern of incomplete dominance in their
relationship to traits and behaviors
• Incomplete dominance refers to a situation
where the effects of dominant and recessive
alleles are blended and then expressed in a
phenotype
How Do Genes Work to Influence
Predation?
• Complex traits and behaviors are usually not produced
by single genes
• The term “genetic potentials” refers to genes creating
general behavioral tendencies, or propensities, that can
sometimes be contingent on the environment for their
activation
• Single gene influences are also typically rather small,
usually explaining less than 5% of the variance in any
complex behavior – such as violence
How Do Genes Work to Influence
Predation?
• In studying predatory offenders, there’s one overriding,
consistent, and obvious fact – predatory offenders are
universally male
• The male brain has 10% more area dedicated to
aggression
• Males are generally more status oriented and ascribe to
status hierarchies – which are also known as dominance
hierarchies
How Do Genes Work to Influence
Predation?
• Dominance can be achieved through a variety of
methods, but the most efficient method employed
more frequently by males than females is violence
• Dominance fueled by testosterone may be why overt
physical aggression and predatory behavior in males
appears to fully materialize during adolescence
• The amygdale is the “seat of emotions and emotional
memory” – which is of particular interest to the study
of predatory criminal behavior
How Do Genes Work to Influence
Predation?
• The amygdale provides humans with the ability to
match an event to a specific emotion and thereby
gives us the ability to recall the experiences as well
as the feelings associated with the experience
• Several studies show that empathy is absent in
psychopaths and that its absence is due to problems
associated with amygdale responses
• The last part of the brain to develop is the neocortex
– or the “thinking part” – which is responsible for the
human abilities of planning, delaying gratification,
impulse control, and rational thought
How Do Genes Work to Influence
Predation?
• The cortex houses the “executive functions” of
the brain – such as self-control and emotional
regulation
• Numerous studies have shown that the cortex is
critical to prosocial human behavior
• Certain individuals appear to lack self-control
because of deficits in the ventrolateral prefrontal
cortex – especially deficits in the left hemisphere
How Do Genes Work to Influence
Predation?
• This pattern of findings is particularly striking for males,
whose brains are more at-risk for neurological insult and
who have more problems with impulse control
• All sensory input is channeled 1st to the limbic system
• When strong emotions are encountered, the initial limbic
impulse may be to act with violence, or to act aggressively
• The cortex may intervene to curtail or modify the initial
limbic impulse – obviously, deficits in the cortex will allow
those impulses to materialize in the form of behavior
How Do Genes Work to Influence
Predation?
• Those with the inefficient allele were thought to have excess
serotonin – which, theoretically, would increase impulsivity
• Individuals with inefficient allele showed substantial reductions
in brain volume in areas of the brain that control attention and
emotions
• Further evaluation found that the OFC was less active and
less connected to the amygdala in men with the inefficient
allele
– Recall that the OFC is deeply implicated in self-control and
emotional regulation
How Do Genes Work to Influence
Predation?
• The human genetics is related to predatory offending through
3 primary variables: sex, brain structure and functioning, and
neurotransmission
• How the genotype codes for these biological factors plays a
large role in the resulting expression of criminogenic traits
• Genotype is also influenced by environmental variables –
such as the induction of neurotoxins and constant stress and
anxiety
• It’s not clear that serious offenders would behave differently
even if presented with entirely prosocial environmental stimuli
Criminality
• Genome may not influence behavior directly – that is,
genes do not cause behavior
• Instead, genes create the conditions for various
human traits to be expressed in terms of personality,
thinking patterns, and ultimately behavior
• The concentration of these traits within an individual
elevates the likelihood that he will engage in
predatory conduct for much of his life
Criminality
• Predatory offenders often have problems with selfcontrol – in that they act impulsively and sometimes
without accurately assessing the immediate situation
• They tend to be narcissistic, thinking primarily of
themselves and their needs and wants, and they
appear unable to relate to the pain and anguish they
cause others
• They also tend to be below average in measures of
IQ, especially on measures of verbal IQ
Criminality
• They tend to view the world negatively, with open hostility
towards others, and they tend to act aggressively with
provocation
• Theirs is also a lifestyle of drug-use, partying, and general
irresponsibility
• Criminality, or the propensity to commit crime and other
destructive behaviors, manifests itself from the
confluences of these traits
Criminality
•
A behavioral genetic understanding of these traits
highlights 2 inter-related points:
1. All of these traits have high levels of heritability,
especially IQ, impulsiveness, and self-control
2. Many individuals suffer from relatively low levels of
self-control, have high levels of impulsivity, and are
non-empathetic but are not criminal
Conclusions
• Behavioral genetics have yet to fully penetrate
criminology
– One reason for this is that many criminologists fear
that recognizing genetic influences will leave them
with nothing left to study
• Understanding predation from a behavioral genetic
viewpoint does not obviate the importance of
environmental factors
Conclusions
• A behavioral genetic viewpoint helps to clarify how
environmental stimuli operate on the human organism and
it helps to specify more precisely which stimuli sponsor
criminality and which do not
• Genetic influences on criminality are complex and
multifaceted – It’s simply not the case that “bad genes”
create “bad” people
• There’s ample reason to believe that serious misbehavior
may also respond well to the combination of
pharmaceuticals and individual and family counseling
Conclusions
• The earlier the age of onset of problem behaviors the
more likely those problems are to become resistant
to change
• This evidence points to the need for early
intervention with high-risk children and their families
• It’s unreasonable to expect that even our best efforts
to habilitate or rehabilitate a criminal individual will be
successful in all cases
Conclusions
• Even among offenders, serious predation is not
common – the crimes these men commit are
typically the most serious and the most brutal
• Perhaps the most important contribution to
behavioral genetics is its focus on consilience
• As an overarching perspective, the field of
behavior genetics offers invaluable insights into
the origins of predatory criminal conduct