3.1.1 Bio exp. 1 : inherited criminality Flashcards
certain individuals have a ____ ____ to commit a crime
genetic predisposition
What did Lombroso introduce?
An early theory on criminal behaviour that claimed criminals possessed similar characteristics to lower primates
What type of form did Lombroso suggest criminals possessed?
- Atavistic Type
What are the 6 signs of Atavistic Type?
- narrow sloping brow
- ears of unusual size
- nose twisted/flattened
- nose beak-like (murderers)
- long arms
- extra fingers/toes
What did Galton suggest?
That there are 3 basic research methods that should be used to study the interaction
between nature and nurture
one is twin studies
What are the 3 types of studies (Galton)
- Family studies
- Twin studies
- Adoption studies
What happens during a twin study?
- Most rely on twins raised in the same family
Monozygotic
MZ or identical
twins share all the same genes
Dizgotic
DZ or fraternal
twins share only 50% of genes
Raine (1993)
reviewed research on the delinquent behaviour of twins and found a 52% concordance for MZ twins compared to 21% for DZ twins
what did McGuffin & Gottesman (1985) find
A concordance rate for aggressive and antisocial behaviour
MZ twins = 87%
DZ twins = 72%
what do Raine’s findings suggest?
Criminality is inherited -
MZ had higher delinquent behaviour levels than DZ
what do adoption studies focus on?
The criminal records of individuals in comparison to the criminal records of their biological parents (genetics) and adoptive parents (environment)
Hutchings and Mednick (1973)
Reviewed over 14,000 adoptions in Denmark
They found a significant positive correlation between number of convictions for criminal violence among the biological parents and number of convictions for criminal violence among their adopted sons
Bohman (1995)
considered how genes and the environment actually interact
found there was more chance of criminality when there was a genetic risk factor together with an environmental risk factor
Biological parents with criminal record + adoptive parents with criminal record
vunerability to crime
children = 40% vulnerability to crime
Biological parents with criminal record + adoptive parents without criminal record
vunerability to crime
children = 12% vulnerability to crime
Biological parents without criminal record + adoptive parents with criminal record
vunerability to crime
children = 7% vulnerability to crime
Biological parents without criminal record + adoptive parents without criminal record
vunerability to crime
children = 3% vulnerability to crime
What is the MAOA gene?
A gene responsible for producing the enzyme Monomine Oxidase
What is monomine oxidase (MAOA)?
Monoamine oxidase A (MAOA) is an enzyme that
breaks down important neurotransmitters in the
brain, including dopamine and serotonin
What can low levels of serotonin associate to?
Low levels of serotonin have been associated with impulsive and aggressive behaviour.
Brunner et al. (1993)
Completed a pioneering study of a Dutch family with several generations of
violent males, clinical geneticist
what did Brunner et al. (1993) find
The first tangible evidence of a direct link between molecular biology (a
MAOA deficiency) and aggressive
behaviour in humans.
Chromosome findings of Brunner et al. (1993)
Found anomalies of X chromosome were present in all violent men but NOT non-violent men
Found excess amounts of all 3 neurotransmitters in men’s urine - better explained by shared environmental factors
What are epigenetics?
Refers to the material in each cell of the body that acts like a set of ‘switches’ to turn genes on or off (epigenomes) which in turn have been affected by environmental factors - stress diathesis
What is the stress-diathesis?
Predisposition through abnormality of hte brain, genes or trauma
What is diathesis- stress
Predisposition or vulnerability through abnormality of brain, genes or trauma
Capsi et al. (2002)- effects of nature & nurture
maltreatment + high amount of MAOA = less likely to show antisocial behaviour
maltreatment + low levels of MAOA = 3x more likely to display anti-social behaviour
What was Capsi et al. (2002) conclusion?
That both levels of MAOA and maltreatment contributes to behaviour - genes + environmental
