Twin Studies

Question 1

What are twin studies?

Answer 1

Twin studies are a well-known method for identifying a genetic basis of behaviour.

Question 2

How do we study twins

Answer 2

By examining monozygotic (identical) twins and dizygotic (non-identical) twins (who share 100% and 50% of their genetic make-up respectively) concordance rates can help go indicate a possible genetic tendency.

Question 3

Christiansen (1977)

Answer 3

Examined over 3,500 twin pairs in Denmark and identified concordance rates of criminal behaviour

Question 4

Results of his study

Answer 4

MONOZYGOTIC TWINS
Male 35%
Female 21%
DIZYGOTIC TWINS
Male 13%
Female 8%

Question 5

What does this data show?

Answer 5

Male twins are more likely to be criminal, than females.
Monozygotic twins are more likely to be criminal.
If there is a gene that causes crime its more prevalent on the Y chromosome.