Biological theories into Criminality
- Created by: Nevesaunders
- Created on: 13-11-18 10:59
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- Biological theories into criminality
- Genetic theories
- XYY theory
- Presence of an extra y chromosome
- 'Super males' are more of an interests to criminologists
- Jacobs et al found that XYY men are more aggressive and violent
- Found that XYY is overpopulated in prisons
- John Wayne Gacy had XYY syndrome and murdered and tortured 33 young males.
- Twin studies
- Monozygotic- identical twins
- Dizygotic- non identical twins
- Lange found that MZ twins shared a higher degree of concordance than DZ twins for criminal behaviour
- Christiansen found higher rates for MZ twins too
- Adoption studies
- Comparison of biological and adoptive parents
- Hutching and Mednick studied adopted children and found a high proportion with criminal convictions also had biological parents with criminal convictions
- Mednick et al found no connection between adopted children and adoptive parents
- XYY theory
- Physiological theories
- Lombroso
- Argued that criminal is a separate species, between modern and primate humans
- Argued that a 'born criminal' could be determined by physical shape of head/features
- Atavistic or primitive features
- Examined facial features of 4,000 living criminals and 400 dead. 40% accounted for by atavistic features
- Study in Chinese uni researched ID pics, half with criminal convictions. Correctly identidied 80% of real criminals
- Sheldon
- Advanced Lombroso's theory, linked criminal behaviour to physical form
- Examined 4000 scantily clothed men and put forward fundamental somatotypes
- Endomorphic- fat and soft, tend to be sociable and relaxed
- Ectomorphic- thin and fragile, introverted and restrained
- Mesomorphic- muscular and hard, aggressive and adventurous
- Found criminals were more prone to being mesomorphic and least likely ectomorphic
- Brain scans
- Raine et al used PET scans to study the brains of impulsive killers
- Found damage on the pre frontal cortex, controls impulsive behaviour
- Case study: Phineas Gage
- Iron rod went through his head, destroyed left frontal lobe. Behaviour and personality changed
- He became anti-social, used bad language and had bad manners
- Raine et al used PET scans to study the brains of impulsive killers
- Neuro-chemical
- Brain can be affected by diet and blood sugar levels
- Low serotonin levels are linked with higher agression
- Large about of steroids can increase violence
- Lombroso
- Genetic theories
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