Genetic Explanations Of Offending Behaviour

Question 1

Which debate supports this?

Answer 1

Nature - twin studies are used (MZ) and (DZ) twins. The research assumes each twin has similar life experiences

Question 2

Cloninger et al (1978)

Answer 2

• 0.7 correlation between MZ twins
• 0.4 for DZ in terms of their criminality versus their non-criminality

= genetic connection
- critics cite the fact that MZ twins are much more likely to be treated and brought up in the same way than DZ twins
= may contribute their shared likelihood of entering into offending behaviour

Question 3

Adoption studies

Answer 3

Child’s relationship to both adoptive and biological parents can be compared.

Question 4

Mednick, Gabrielli and Hutchings (1984)

Answer 4

Large study - sampling over 14000 adopted individuals
= corrélation between criminal convictions of the adoptee and natural parents

= No relationship with adoptive parents

• Correlation only true for certain crimes; theft NOT violent crimes
• Critics - children often are adopted into family situations similar to those of their biological parents = difficult to differentiate nature-nurture influences

Question 5

XYY

Answer 5

• lead to more aggression due to hyper-masculinity
• May be a larger proportion of XXY men in prison or psychiatric hospitals
• Research backs it up - rare but more common in men involved in crime
• Noted that many of these criminals were not involved in violent crime - might have been expected from XXY chromosome hypothesis
• Due to lack of any substantive evidence the XXY theory is now largely defunct in the forensic psychology field.