BIOLOGICAL - GENETIC STUDIES - TWIN STUDIES

Question 1

What is the basic idea?

Answer 1

The idea that a heritable trait may increase the risk of criminal behaviour

Question 2

what is a monozygotic twin?

Answer 2

An identical twin, from one egg, share 100% dna

Question 3

what are dizygotic twins ?

Answer 3

NON identical twins, 50% dna shared, two separate eggs

Question 4

what is a concordance rate?

Answer 4

where twins share characteristics or act in a similar way

Question 5

Summarise the 1929 study by johannes lang

Answer 5

investigated 13 MZ twins and 17 DZ twins where one of the twins in each pair had served time in prison.Lange found that 10 MZ twins but only 2 DZ twins had a co-twin who was also in prison.Lange concluded that genetic factors play an important role in offending behaviour.a study of 30 pairs found that 10/13 MZ twins had served time in prison, the concordance rate for DZ twins was 2/17

Question 6

Name a strength ?

Answer 6

MZ twins are genetically the same it makes sense to research if the offending behaviour is the same

Question 7

What did ishikawa and raine find?

Answer 7

higher concordance rate for identical than non-identical twins

Question 8

Name a limitation?

Answer 8

If genes were the only cause of criminality, then there would be 100% concordance between twins when one of them offends, but studies only show around half or less making them unreliable and lacking any correlation.