Genetic theories of criminality
- Created by: StarrWinchester
- Created on: 13-02-20 20:29
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- Genetic theories of criminality
- Assumes criminality is inherited and/or a result of genetic abnormalities
- Twin studies
- Twin studies are conducted to allow us to examine the extent a specific trait such as criminality, is a result of genes or the environment
- Monozygotic twins are identical, and come from the same egg. Dizygotic twins are non identical and come from two separate eggs
- Concordance rates are the probability that a pair of individuals will both have a certain characteristic.
- CHRISTIANSEN (1977)
- He examined over 3,500 twin pairs from Denmark. Studied both monozygotic and dizygotic
- Found that concordance rates in MZ twins was 35%. For DZ twins it was 15%
- The more genetically similar, the more similar they were in criminal behaviour
- Found that concordance rates in MZ twins was 35%. For DZ twins it was 15%
- He examined over 3,500 twin pairs from Denmark. Studied both monozygotic and dizygotic
- Twin studies are conducted to allow us to examine the extent a specific trait such as criminality, is a result of genes or the environment
- Family studies
- Family studies are conducted to see if behaviour is inherited. The findings could be used to help predict behaviour and see the degree of risk a child may turn criminal
- Brunner (1993)
- Investigated a family in the Netherlands who had a high number of males involved in crime
- Found that they had a genetic mutation of the X chromosome
- This resulted in a deficiency in the MAOA enzyme which helps regulate neurotransmitters like seratonin
- This became known as the warrior gene as it has been linked to aggression
- This resulted in a deficiency in the MAOA enzyme which helps regulate neurotransmitters like seratonin
- Found that they had a genetic mutation of the X chromosome
- Investigated a family in the Netherlands who had a high number of males involved in crime
- Jacobs XYY (1965)
- XYY syndrome is when a male has an extra Y chromosome
- Jacobs studied inmates of a Scottish maximum security hospital.
- 1 in 28 of the men had the extra Y chromosome. They were described as "dangerous, violent criminals"
- Jacobs studied inmates of a Scottish maximum security hospital.
- XYY syndrome is when a male has an extra Y chromosome
- Adoption Studies
- Adoption studies are conducted to help with our understanding of whether behaviour is due to nature or nurture
- Crowe (1972)
- Crowe compared adopted children who's biological mother had a criminal record with adopted children who's biological mother did not.
- 50% of children who's biological mother had a criminal record also had one by the age of 18
- Only 5% of the adopted children who's biological mother did not have a criminal record had one by the time there were 18
- 50% of children who's biological mother had a criminal record also had one by the age of 18
- Crowe compared adopted children who's biological mother had a criminal record with adopted children who's biological mother did not.
- Crowe (1972)
- Adoption studies are conducted to help with our understanding of whether behaviour is due to nature or nurture
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