Chapter 3- The Behavioral Genetics of Predatory Criminal .ppt

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1、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 validThe media frequently reports startling

2、results linking brain functioning to criminal behavior, or reports new linkages between specific genes and criminal traitsThis 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” (R

3、obinson, 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 offendingIn particular we provide the reader a brief introduction on what is known about:Predatory offending, about the fundam

4、entals 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 perso

5、nEven 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 influenceThe difference is that predatory offenders do not

6、 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:An amazing wealth of data converge to show that the warning signs for serious predation a

7、re visible in infancy and childhoodTraits related to later criminal conduct are also visible in infancy and early childhoodStudies 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 un

8、iversal human capacity, is “normal” early in life, but becomes more uncommon in children over timePerhaps not surprisingly, an early age of onset is one of the strongest predictors of future adult predatory offendingMoreover, virtually every predatory offender has experienced an early age of onset,A

9、 Behavioral Genetic Understanding of Predatory Offending,Traditional criminological theories remain silent largely because these theories of crime locate the causes of misconduct in adolescenceCriminologists would likely point to parental rearing environments as the putative source variation in youn

10、g childrens behaviorsBut 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 influencesAt the heart of the field is the

11、estimation of genetic and environmental influencesBehavioral 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

12、 more different than alikeShared environments: are thought to make people more alikeFindings 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 especiall

13、y those associated with predatory offending genetic influences dominateThe behavioral genetic studies typically show that shared environments have little to no effect on their adult offspringThe processes that link parenting practices to human development likely operate through biological mechanisms

14、,A Brief Note on Human Genetics,Human-beings inherent 22 pairs of chromosomes from each parent, plus 1 sex differentiating chromosomeDNA is composed of 2 elongated sections bonded to chemical bases the now familiar double-helixGenes, which are embedded in chromosomes, are merely stretches of DNA wit

15、h 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 motherGenes play a significant role in serious, predatory behaviorEven with multiple copies of some genes, they are not all turn

16、ed 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 imprintingGenes come in different varieties differences in genes are called allelesAllelic variation occurs when mutations, genetic drift, culture or evolution alters a

17、 geneGenes 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 principlesFunctional human genes appear to

18、 follow a pattern of incomplete dominance in their relationship to traits and behaviorsIncomplete 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 a

19、re usually not produced by single genesThe term “genetic potentials” refers to genes creating general behavioral tendencies, or propensities, that can sometimes be contingent on the environment for their activationSingle gene influences are also typically rather small, usually explaining less than 5

20、% of the variance in any complex behavior such as violence,How Do Genes Work to Influence Predation?,In studying predatory offenders, theres one overriding, consistent, and obvious fact predatory offenders are universally maleThe male brain has 10% more area dedicated to aggressionMales are generall

21、y 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 violenceDominance f

22、ueled by testosterone may be why overt physical aggression and predatory behavior in males appears to fully materialize during adolescenceThe 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 Influ

23、ence 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 d

24、ue to problems associated with amygdale responsesThe 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

25、houses the “executive functions” of the brain such as self-control and emotional regulationNumerous studies have shown that the cortex is critical to prosocial human behaviorCertain individuals appear to lack self-control because of deficits in the ventrolateral prefrontal cortex especially deficits

26、 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 controlAll sensory input is channeled 1st to the limbic systemWhen strong emoti

27、ons are encountered, the initial limbic impulse may be to act with violence, or to act aggressivelyThe 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 Influenc

28、e Predation?,Those with the inefficient allele were thought to have excess serotonin which, theoretically, would increase impulsivityIndividuals with inefficient allele showed substantial reductions in brain volume in areas of the brain that control attention and emotionsFurther evaluation found tha

29、t the OFC was less active and less connected to the amygdala in men with the inefficient alleleRecall 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:

30、 sex, brain structure and functioning, and neurotransmissionHow the genotype codes for these biological factors plays a large role in the resulting expression of criminogenic traitsGenotype is also influenced by environmental variables such as the induction of neurotoxins and constant stress and anx

31、ietyIts 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 behaviorInstead, genes create the conditions for various human traits to be expressed i

32、n terms of personality, thinking patterns, and ultimately behaviorThe 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 self-control in that they act impuls

33、ively and sometimes without accurately assessing the immediate situationThey 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 othersThey also tend to be below average in measures of IQ, especially

34、 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 provocationTheirs is also a lifestyle of drug-use, partying, and general irresponsibilityCriminality, or the propensity to commit crime and other d

35、estructive behaviors, manifests itself from the confluences of these traits,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-controlMany individuals suffer fro

36、m 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 criminologyOne reason for this is that many criminologists fear that recognizing genetic influences will leave them with n

37、othing left to studyUnderstanding 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 st

38、imuli sponsor criminality and which do notGenetic influences on criminality are complex and multifaceted Its simply not the case that “bad genes” create “bad” peopleTheres ample reason to believe that serious misbehavior may also respond well to the combination of pharmaceuticals and individual and

39、family counseling,Conclusions,The earlier the age of onset of problem behaviors the more likely those problems are to become resistant to changeThis evidence points to the need for early intervention with high-risk children and their familiesIts unreasonable to expect that even our best efforts to h

40、abilitate 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 brutalPerhaps the most important contribution to behavioral genetics is its focus on consilienceAs an overarching perspective, the field of behavior genetics offers invaluable insights into the origins of predatory criminal conduct,