Chapter 3: The Behavioral Genetics of Predatory Criminal Behavior

1. Chapter 3: The Behavioral Genetics of Predatory Criminal Behavior John Paul Wright Kevin M. Beaver

2. 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)

3. 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

4. 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

5. The Roots of Predation • Research findings on the development of serious criminal conduct have revealed 3 important findings: • An amazing wealth of data converge to show that the warning signs for serious predation are visible in infancy and childhood • Traits related to later criminal conduct are also visible in infancy and early childhood • Studies into the development of aggression have found that its onset occurs around the time when children gain mobility

6. 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

7. 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?

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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

24. Criminality • Predatory offenders often have problems with self-control – 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

25. 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

26. Criminality • A behavioral genetic understanding of these traits highlights 2 inter-related points: • All of these traits have high levels of heritability, especially IQ, impulsiveness, and self-control • Many individuals suffer from relatively low levels of self-control, have high levels of impulsivity, and are non-empathetic but are not criminal

27. 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

28. 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

29. 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

30. 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