Twin Studies

Question 1

What is it?

Answer 1

A way of testing if crime is genetic in families.
Do this bc MZ twins (identical) share exact same genes. So if one was criminal the other would too
DZ twins share 50%

Question 2

Evidence from Christiansen’s study

Answer 2

From a sample of 3,856 twin pairs.

52% concordance rate between MZ twins.
DZ twins (non-identical) had a 44% concordance rate.

Question 3

Strengths

Answer 3

MZ twins = genetically identical, therefore logical to examine their offending is also identical.
Twin studies give some support to genetic explanations, Ishikawa and Raine found higher concordance rate for MZ than DZ

Question 4

Weaknesses

Answer 4

Impossible to isolate and measure the effect of genes separately from environmental factors.
If genes = only cause of criminality, MZ twins would show 100% concordance rate not 52%