Unit 2 AC2.1 Genetic Theories

Question 1

Why are adoption studies conducted?

Answer 1

They can help with our understanding of whether behaviour is due to nature or nurture as their environments will have been different from one another

Question 2

Crowe (1972)

Answer 2

compared adopted children with a biological mother with a criminal record to a group of adopted children whose mother did not have a criminal record.

Question 3

Crowe (1972) Percentage?

Answer 3

50% B.M w/ record

5% B.M w/o record

Question 4

Crowe (1972) Evaluation

Answer 4

Useful - allows us to see the relative importance of nature vs nurture
Reductionist - criminality is likely a combination of factors rather than a simplified explanation

Question 5

Why are family studies conducted?

Answer 5

To see if behaviour is inherited. findings could be used to help predict behaviour

Question 6

Brunner (1993)

Answer 6

Investigated a family in the Netherlands who’d been involved in crime . was found that males in the family had a genetic mutation of the X chromosome. This resulted in a deficiency in the enzyme (MAOA).

Question 7

What does MAOA do?

Answer 7

MAOA helps regulate neurotransmitters such as serotonin (too much has been linked to aggression). This became known as the Warrior Gene and it’s suggested that this gene can make someone more likely to be a criminal.

Question 8

Brunner (1993) Evaluation

Answer 8

Deterministic - Means there is a cause for criminality and behaviour is therefore predictable. However, it absolves criminals of responsibility if we assume they lack free will.

Question 9

Jacobs XYY (1965)

Answer 9

XYY syndrome is when a male has an extra Y chromosome. Jacobs studied inmates of a Scottish maximum security hospital. The males had been described as ‘dangerous, violent criminals’. doesn’t necessarily suggest criminality is inherited but that there could be a link between genes and crime.

Question 10

Jacobs XYY (1965) XYY in hospital compared to general population

Answer 10

1 in 28 of these participants were XYY males. General population - 1 in 1000.

Question 11

Jacobs XYY (1965) Evaluation

Answer 11

Useful - Shows an association between the gene and offenders imprisoned for violent crimes. However, XYY males often have low IQ, meaning they’re more likely to be caught and therefore skew the perceptions of those with the defect

Question 12

Why are twin studies conducted?

Answer 12

allow us to examine the extent a specific trait (such as criminality) is a result of genes or the environment.

Question 13

Monozygotic and Dizygotic

Answer 13

Monozygotic – Identical twins/from one egg

Dizygotic – Non-identical twins/from two eggs

Question 14

What are concordance rates?

Answer 14

The probability that a pair of individuals will both have a certain characteristic

Question 15

Concordance rate example

Answer 15

In a pair of MZ twins, if one has schizophrenia, the other is about 50% likely to be diagnosed with the disease. In DZ twins, the concordance rate drops to about 15%. genetics are partially to blame for schizophrenia, though not entirely, or the concordance rate for identical twins would be 100%.

Question 16

Christiansen (1977)

Answer 16

Examined over 3,500 twin pairs from Denmark. They looked at identical and non-identical twins to find out the C.R of criminality.

Question 17

Christiansen (1977) C.R

Answer 17

the concordance rate for the male MZ twins was 35% whereas the concordance rate for the male DZ twins was only 13% .the more genetically similar, the more similar the twins were in their criminal behaviour

Question 18

Christiansen (1977) Evaluation

Answer 18

Logical- examines whether twins offender behaviour is similar, which in this study it is. However, concordance rates are low, in this study, so it is likely that criminality is also a result of environmental influences.