biological theories (genetic) Flashcards
What did Lombroso claim about crime?
Crime is inborn and presumably passed down from parents to child.
What did the Cambridge study in delinquents development find?
Half of all criminal convictions came from just 23 families out of 397.
What did Osborn and West discover about sons of criminal fathers?
They were much more likely to have a criminal record.
What is the significance of twin studies in genetic theories of crime?
They test the theory of criminality by examining identical twins.
Define monozygotic twins.
Identical twins who share 100% of the same genes.
Define dizygotic twins.
Non-identical twins who share 50% of the same genes.
What was the concordance rate found by Christiansen’s study for monozygotic twins?
52% concordance rate.
What was the concordance rate for dizygotic twins in Christiansen’s study?
22% concordance rate.
What did Ishikawa and Raine find regarding concordance rates?
44% for identical twins and 21.6% for non-identical twins.
What is a limitation of twin studies regarding environmental factors?
High concordance rates may be due to shared environments, not just genetics.
Why might identical twins have similar criminal behavior apart from genetics?
They may be treated more alike and feel closer than non-identical twins.
What is a major limitation in isolating genetic effects from environmental factors?
It’s impossible to measure the effects of genes separately from environmental factors.
What was a challenge in early studies of twins?
There was no way to confirm if twins were genetically identical without DNA testing.
Fill in the blank: Monozygotic twins share _______ of the same genes.
100%
Fill in the blank: Dizygotic twins share _______ of the same genes.
50%
True or False: If genes were the only cause of criminality, identical twins would show 100% concordance.
True
What does the concordance rate measure?
The probability of both twins being criminal if one of them is.
What is the basis of adoption studies in criminology?
Adopted children share the environment of their adoptive parents but the genes of their biological parents.
What did Mednick et al’s study on adopted sons in Denmark find?
Sons were more likely to have a criminal record if a birth parent also had a record (20% concordance rate).
How did Hutchings and Mednick’s comparison of adoptees contribute to the genetic explanation of crime?
Adoptees with criminal records were more likely to have biological parents with criminal records.
What is one strength of adoption studies?
They allow us to see the relative importance of nature (genes) vs nurture.
What is a limitation of adoption studies?
Adopted children are placed in environments similar to those they would have if with biological parents.
What is XYY syndrome?
An abnormality characterized by an extra Y chromosome, often associated with being very tall and well-built.
What is the significance of the Y chromosome?
It determines whether a child is male.
