Twin Studies Flashcards
What are the two types of twins and what is the distinction between them?
Monozygotic- identical twins, share 100% the same DNA
Dizygotic- fraternal twins, share 50% of the same DNA
What is meant by concordance rate?
The probability that if one twin has a characteristic the other will have the characteristics
What does twins studies aim to do?
They use monozygotic twins to test theories since they have the same DNA and identical genes, aiming to see if criminality is actually biological or environmental.
What is one of the earliest twin studies that can be used as evidence for twin theory?
Lange,
Investigated 13 monozygotic twins and 17 dizygotic twins. And found that 10 out of the 13 monozygotic twins had both served time in prison compared with 2 out of 17 dizygotic twins, suggesting that criminality perhaps due to biological factors like genes and DNA.
What was Christensen’s study?
Analysed pairs of twins in an effort to determine whether criminality perhaps tendencies might be inherited.
Investigated 3586 twin pairs and found 52% concordance rate between monozygotic twins compared with 22% concordance rate for dizygotic twins.
What are some evaluations of twin studies?
Strength-twins studies give some support to genetic explanations of crime, because as identical twins are genetically identical, if one is a criminal, the other should be too.
Limitation- if genetics were the only cause of criminality then the concordance rates should be 100% for monozygotic twins. It also doesn’t take into account environmental factors affecting criminality.
