genetic explanations of offending

Question 1

what did lange (30) study in their twin studies

Answer 1

• 12 mz twins and 17 dz twins
• one of each twin had served in prison
• 10 of mz twins but only 2 of the dz twins has a co twin who had also offended

Question 2

what did christiansen (77) study in the twin studies

Answer 2

• studied 87 mz and 147 dz twins
• found a concordance rate for both twins to offend
• mz = 33%
• dz= 12%

Question 3

what is the term concordance

Answer 3

the presence of the same trait in both twins

Question 4

what is the conclusion of the twin studies

Answer 4

that genes play a role as in both studies the mz twins had a higher concordance rate

Question 5

what did tiihonen do to discover a violent gene

Answer 5

• genetic analysis of 900 finnish offenders

Question 6

what two genes did tiihonen reveal

Answer 6

• MAOA
• CDH13

Question 7

what is the maoa gene

Answer 7

control dopamine and seratonin, linked to agression

Question 8

what is the cdh13 gene

Answer 8

linked to substance abuse and attention deficit disorder (add)

Question 9

how may more times are people with these genes likely to offend

Answer 9

people with both of the genes are 13x more likely to offend

Question 10

whats a weakness of tiihonens gene study

Answer 10

it hasnt been replicated so we dont know the reliability of the assumption

Question 11

why does the theory have biological reductionism

Answer 11

• by reducing criminal behaviour to genetic or neural explantion is over simplifying it
• mz twins also never show 100% concordance rates for criminal behaviour

Question 12

why does the theory have biological determinism

Answer 12

the idea of a criminal gene allows offenders to say they weren’t acting under free will and therefore may require a less severe form of punishment or rehabilitation.

Question 13

what are the problems with the twin studies

Answer 13

• it was poorly controlled and zygosity was based on apperance not dna
• sample sizes were small and unrepresentative

Question 14

why is there is support for the stress diathesis model

Answer 14

mednicks adoption studies show that there is both a genetic and environmental influence of criminal behaviour

Question 15

what are the problems with adoption studies

Answer 15

• they create ethical issues as some child experiences late adoption and others continue with their biological familes
• the findings also only work on petty crimes ie buglary and not serious crimes