Biological explanation: Genetic

Question 1

Candidate genes:

Answer 1

Criminality could be the result of faulty candiate genes

Question 2

The warrior gene:

Answer 2

• Faulty MAOA gene can result in higher levels of serotonin than usual
• serotonin stabilises mood, if mood is unstable it leads to higher aggression which leads to violent crimes

Question 3

Brunner:

Answer 3

• 28 male family members studied
• All showed violent and impulsive behaviour
• All males had a faulty MAOH gene

Question 4

Tihonen:

Answer 4

• Genetically analysed 900 offenders
• Found abnormalities on two genes that may be associated with crime
• MAOA - serotonin - linked to aggressive crimes
• CDH13 - linked to substance abuse - due to impulsive behaviour

Question 5

Twin studies: Christiansen

Answer 5

• The results of twin studies looking into the concordance rates of criminality have found that offender behaviour in 35% of identical twins
• Whereas in non-identical twins it is only 13%
• This means that offender behaviour can be inherited through DNA but also has underlying predisposing traits

Question 6

Adoption studies: Crowe

Answer 6

• Adopted children whose biological mum had a criminal record had a 50% chance of having a criminal record
• Control group = 5%
• This means that offender genes can be inherited from a first degree relative

Question 7

Limitation of genetics

Answer 7

Not entirely genetic:
- Concordance rates from twin studies are less than 100%, this means that there is space for environmental factors to affect criminal behaviour
- This shows that twin studies don’t provide support for complete biological explanation of offending behaviour
- This shows that biological explanations are only a partial explanation of offending behaviour

Mediating factors:
- There are mediating variables that affect offending behaviour
- For example childhood experiences can affect the likelihood of someone becoming an offender
- This means that other factors may mediate the effects of the biological influences