[GENETIC] Biological - Twin Studies

Question 1

[FAMILY/TWIN STUDIES]

What are the two types of twins

Answer 1

Monozygotic
&
Dizygotic

Question 2

[FAMILY/TWIN STUDIES]

Explain the two types of twins and behaviour as a result of genes

Answer 2

Monozygotic = Identical twins from one egg, shared DNA, same environment, Behave in a similar way

Dizygotic = non-identical, separate eggs, share 50% of DNA, same environment, same as an ordinary sibling

If behaviour is caused by genes - MZ twins should be more similar than DZ twins (Concordance rate - behaving in a similar way)

Question 3

[FAMILY/TWIN STUDIES]

Explain the link to criminality

Answer 3

If both identical twins are criminal, this suggests a very strong link to criminality

Question 4

[FAMILY/TWIN STUDIES]

Explain the supporting evidence for criminal concordance

Answer 4

Christiansen

Studied 3586 pairs of twins to identify higher concordance rates of criminal behaviour in MZ twins (theft, not violent crimes)

Results: MZ twins has a higher % than DZ twins

Question 5

[FAMILY/TWIN STUDIES]

Explain why the twin studies are more useful than family studies

Answer 5

Takes the nature side of the debate into account and looks into the biology - how genetics have an impact on criminality

Question 6

[FAMILY/TWIN STUDIES]

Explain 3 weaknesses

Answer 6

• We are still seeing impact of environment (nurture)
• small samples may not be representative

-in Christiansen’s study there is a difference in the % depending on gender, raising the question about how gender may affect criminal behaviour

Question 7

[FAMILY/TWIN STUDIES]

Explain a strength

Answer 7

MZ shows higher rate of concordance than DZ, shows genetic similarity (E.G: The Krays)