Biological Theories Of Criminality- Genetic Theories Flashcards
Twin and Adoption Studies
Key idea: Twins
If crime is genetic- identical (Mz) twins should have identical criminality
Twin and Adoption Studies
Twin study findings
Christiansen: Concordance in criminality Mz= 52% vs Dz= 22%
Twin and Adoption Studies
Key idea: adoption
Adoptees share environment of adoptive parents/genes of biological parents. If genetic, criminality will match biological parents more
Twin and Adoption Studies
Adoption study findings
Mednick et al: birth parents concordance= 20% vs. adopted parent concordance= 14.7%
Evaluating Twin and Adoption Studies:
Strength
Twin and adoption studies give some support to genetic explanations
Evaluating Twin and Adoption Studies:
Strength
Adoption studies overcome the problems of isolating genes and environment
Evaluating Twin and Adoption Studies:
Strength
Research design of Adoption studies is logical (nature vs nurture)
Evaluating Twin and Adoption Studies:
Limitation
If criminality was only genetic MZ twins would have 100% concordance
Evaluating Twin and Adoption Studies:
Limitation
It is impossible to isolate genetic and Gefechts fully from environmental ones
Evaluating Twin and Adoption Studies:
Limitation
Adopted children often placed with similar families to their birth family
Jacobs XYY Study:
Key idea
XYY syndrome in males makes them genetically predisposed to criminality
Jacobs XYY Study:
Study
Compared rate of XYY in imprisoned criminals with general population
Jacobs XYY Study:
Findings
Higher than average proportion of inmates had XYY
Jacobs XYY Study:
Features of XYY
Very tall, well-built, low intelligence, high aggression, violent
Evaluating Jacobs XYY Study:
Strength
Jacob et al found association with XYY and violent prisoners
Evaluating Jacobs XYY Study:
Strength
Price and Watmore found links with XYY and property crime
Evaluating Jacobs XYY Study:
Limitation
Having the syndrome doesn’t mean that is the cause of crime
Evaluating Jacobs XYY Study:
Limitation
XYY men fit stereotype of violent offenders- labelling theory
Evaluating Jacobs XYY Study:
Limitation
Low intelligence of XYY may give higher chance of being caught
Evaluating Jacobs XYY Study:
Limitation
Syndrome is too rare to explain much crime
Genetic explanation
Criminality is the result of genes inherited from biological parents
Monozygotic
Identical twins that share 100% of the same genes
Dizygotic
Non-identical twins that share only 50% of the same genes (like ordinary siblings)
Environmental explanation
Criminality is the result of the surroundings a child grows up in
Chromosomes
Made from DNA and protein. Carry genetic information we inherit from our parents. Most people have 23 pairs
Super-male
Another term for XYY syndrome. Those affected carry and extra Y (male) chromosome on one of their 23 pairs
Lombroso: Born Criminals:
Key idea
Criminals are physically different from non-criminals
Lombroso: Born Criminals:
Study
Measured many criminals’ heads and faces
Lombroso: Born Criminals:
Findings
Criminals more likely to have large jaws, long arms, aquiline noses
Lombroso: Born Criminals:
Atavism
Criminals are throwbacks to primitive stage of evolution - pre-social, impulsive, reduced sensitivity to pain
Lombroso: Born Criminals:
Further work
Insane criminals, epileptic criminals. Criminaloids- product of environment
Evaluating Lombroso:
Strength
First person to study crime scientifically
Evaluating Lombroso:
Strength
Shows importance of clinical and historical records of criminals
Evaluating Lombroso:
Strength
Helps to focus on how prevention not punishment
Evaluating Lombroso:
Limitation
No further evidence to link facial features and criminality
Evaluating Lombroso:
Limitation
Did not compare with control groups of non-criminals
Evaluating Lombroso:
Limitation
Racist. Equates criminals with savages/ non-western society
