Chapter 3 Flashcards
Origins of criminal behavior
- children vs. later onset offenders
- major culprits of crime (7)
- Genes and antisocial behavior (2 challenges)
- Children who show antisocial behavior often exhibit biochem abnormalities while later onset offenders more influenced by social factors
- Greed, desire for power, glorification of violence, poverty, high unemployment, poor edu, faulty parenting, and group values that deviate from norms are major culprits of crime
- little scientific doubt that genes play a role in antisocial behavior. Challenging questions are
1. Determing how much is influenced by genes (use of adoption/twin studies)
2. Finding which genes are responsible (Investigate associations between polymorphisms, DAT1 & 5hTT, and criminal behavior/low self-control)
Biopsychologists
study bio aspects of behavior, try to determimne which genetic variables play part in criminal behavior, how important they are, and how to modify them. They don’t believe that genetics are sole or prim cause of human behavior
Genetics and Antisocial Behavior
- two methods of genetic research
- Behavior Genetics – examins role genes play in formation and developemnt of human behavior. Investigates relationships between genes and enviro in determing individual diffs in behavior. Has advantage of clearly distinguising genetic from environmental influences
- Molecular Genetics- studies structures and functions of genes at molecular level. Focuses on specific genes as foundations for certain behavior. All info needed to construct a mammal is containted in 100,000 genes. Studies how genes from generations are transferred. Concentrates on polymers of DNA.
Behavior Genetics
- 3 reasons for behavioral diffs
- studies
- Traditional behavior genetics view behavioral diffs as result of 3 genetic or enviro sources:
1. Influences attributable to genetic effects
2. Enviromental influences shared by siblings
3. Influences that aris from nshared enviro exps that makes siblings diff - Magnitude of these gentic and enviro influences usually obtained from stat analyses comparing identical twins to fraternal. One way to determine role of genetics in crime is to compare incidence and type of delinquency among identical and fraternal twins
Dizygotic twins vs. Monzygotic
- prenatal enviros
- temperament in twins
- AKA fraternal develop from two fertalized eggs and are nor ore genetically alike than nontwins; share one half of genes
- AKA identical develop from single egg, always-same sex and share same genes
- Approx 2/3rds of MZ twins are monchorionic (share same chorion) and 1/3rd of the MZ pair is dichorionic (2 diff chorions). Chorion is outer membrane enclosing embryo. Therefore, some identical twins develop in slightly diff prenatal enviros which may contribute to some imdivid diffs
- -Study shows that the temperaments (emotional tone) became more similar for identical twins than frat when they go older
Twin studies
- research on genes and their role (%)
- influences (2)
- additional influences
- Data shows genes influence approx 50% of pop variation in antisocial behavior, indicating the genetic role. However this is only ½ leaving room for enviro influences
1) Genes are not static, fixed and immutable. Envior influences can directly change gene expression
2) Psychosocial influences can result in modifications to DNA that have influences on neuron functioning and behavior - Peer/sibling interactions, child abuse, social modeling, brain injuries can also have neg influences while a positve warm parent can shift beahvior to be prosoical even in those who are genetially vulnerable to antisocial behavior
Shared environments
- % of antisocial
AKA common enviros include prenatal and life exps affecting twins in same way (twins raised by same bio parents)
- Shared enviros are apt to promote high trait or behabior similairty
- Compared to genes that promote 50% of variation in antisocial behavior, shared enviros contribute 15-20%
Non-shared environments
- % antisocial behavior
- shared vs nonshared
- are living exps diff for each twin (being raised in diff home enviro, diff activities, diff schools)
- Nonshared enviors account for 30% of variation in antisocial behavior
- However, developmental factors play a role: twin research shows that for a variety of traits, the magnitude of genetic and nonshared enviro influences increases as a person gets older, where the mag of shared decreases.
Concordance rate
- first research
with %’s
- is the term for degree to which related pairs both show a behavior
- Johannes Lange was first to study concordance and criminality in his book “crime is destiny”. Found crime concordance of 77% for 13 adult identical twins and only 12% for 17 fraternal
The Twin’s Early Development Study
- heritability
- trait
is one of most watched longitudinal twin studies conducted in United Kingdom on sample of twins born in 94,94, 96. Explores behavior problems and problematic development in lang, cognition, and academic abilities from childhood to adolescense
- TED research supports nature and nurture both contributing to behavior
- TEDS research indicates tht nature has considerable influence on behavior problems. Shows antisocial behavior modesdtly influenced by heritability. Also Callous unemotional trait (assoc with antisocial) has very high heritablity and low shared enviro influence
E-risk study
- males vs. females
Study with MZ and DZ twins in E-Risk study. Assessed antisocial behavior thru interviews and enviro risk by amount of maltreatment. Found that maltreatment on risk of antisocial development was strongest among those at high gentic risk (those who are predisposed to be antisocial more likely if maltreated)
-Evidence shows enviro affects fade as move into adulthood but genetic influence remains. This effect stronger in males, female aggression more influence by family enviro
TCHAD
- boys
- later study with girls
• Twin Study of Child and Adolescent Development
- Another longitudal study; gave a behavioral scale to measure parental reported aggression in chidren ages 8-9. Then asked children to report own behavior 8 years later. Used both MZ and DZ twins in effort to distangle genetic factors from enviro
- Found that genetic factors played important role in early onset aggressive behaviors but less important role in delinquent behavior in male adolescents
- Participants where all boys
- However, in a study with girls, genetics had a more import role in both aggressive behaviors in early childhood and delinquent in adolescense
Adoption studies
- point of adoption studies?
- first adoption study
- study of adoptees and criminal parents
- Most comprhensive adoption study
-Helps identify enviros most conductive to criminality
-Schulsinger Denmark Study: explored incidence of psychopahty in bio relatives of adopted adults. Compared 57 adopted psychopathic adults to 57 nonpsychopathic.
Found that 3.9% of bio relatives of psycho adoptess could also be psychopathic whereas only 1.4% of contorl groups bio relatives could (not stat signf)
- found 16% of adoptess of criminal parents had criminal records vs. 8.9% nonadoptes. A check on bio fathers of adoptess showes that they were 3x more likely to committ crime
- Mednick, Gabrielle, Hutchings: Compared court convictions of 14,000 adoptess with conviction records of bio and adop parents. Showed signf relation btween conviction history of adopttes and bio parents. Type of crime crime had no relation
Molecular Genetics
- point of molecular genetics
- mice research
- genes assoc with antisocial behavior
- violent offenders impairments
- other brain research
- Attempts to answer which genes predispose to which kinds of antisocial behavior?
- Research shows that if a MAOA genes is neutrilized in mice they become aggressive
- At least 7 genes identified by molecular genetic research to be assoc with antisocial behavior. They mostly contribute to impairments in brain sturcture and function which result in antisocial behavior.
- Sturctural or functional prob in prefrontal cortex also assoc with impulsive violent offenders
- Some research shows reducded glucose metabolism in prefrontal cortex in murders and reduction of gray matter of criminal psychopaths (due to genes not trauma)
MAOA
MAOA-L (how many have?)
- Monoamine oxidase appears to paly role in preventing antisocial behavior, low activity linked to aggression, nicknamed warrior gene
- carried by 1/3rd of population in Western societies, comes into play in some form of provocation. Those with MAO-L gene who were exposed to adversity in childhood were likely to report offending in adulthood