Biological theories Of Crime Flashcards
Biological theory
Focus on idea that physical characteristics make some people more likely to commit crime than others
Genetic theories
XYY theory
Twin studies
Adoption study
XYY theory
JACOB ET AL 1965- males with XYY chromosome more aggressive and more violent therefore criminal. Significant number of men in prison had XYY chromosomes rather than XY
Positives of XYY theory
Jacob et al 1965- significant number of men in prison had XYY chromosomes.
Adler 2007- aggressive behaviour is atleast partly determined by genetic factors
Negatives of XYY theory
•Outdated
•studies found gene
Tic abnormalities are widespread through population and doesn’t explain aggression
•ignores behaviour approach
• Theilgaard 1984- characteristics of aggression not associated with XYY men
Twin studies
If you are an identical twin your more likely to go to prison
MZ- identical twins
DZ- non identical
Johannes Lange
MZ Twins shoes higher degree of concordance than DX Twins for criminal behaviour.
10/13 MZ Twins in prison whereas 2/17 DZ Twins
Christiansen
Studied 3586 Twins from danish islands and found concordance rates of 35% in MZ and 13% in DZ makes.
21% MZ and 8% DZ female
Positives of twin study
- Natural experiment
- Christiansen supports view that criminality has genetic components
- results of twin studies helped in prevention of vulnerable disorders
Negatives of twin study
- Twin studies not controlled as twins were judged on looks not genetics
- small sample
- twins brought up together so could be nurture
Adoption study
Hutchins and mednick- studied 14000 adopted children and found higher priority ion of those with criminal convictions also had parents with criminal convictions. Persons genetics that influence behaviour
Positives of adoption study
- adopted kids are exposed to doffernt environment to their biological family
- studies found correlation between children and biological parents
- large sample
Negatives of adoption study
- age of adoption may mean they’ve already been influenced by natural parents or foster environment
- info about biological family isn’t always available
- adopted kids placed with parents similar to biological family’s