A2 - Turning to Crime - Biology - Genes & Serotonin Levels

Question 1

What did Jacobs et al find about the XYY syndrome.

Answer 1

In the general population 1 in 1000 men had the XYY syndrome, whereas 15 in 1000 men in the prison population had the XYY syndrome. XYY made people more aggressive, which could be a reason for criminality.

Question 2

What did Price suggest?

Answer 2

Price suggested that males with XYY chromosome were more predisposed to violent crimes.

Question 3

Who conducted the study on genes and serotonin levels?

Answer 3

Brunner et al (1993)

Question 4

What kind of study was it?

Answer 4

A case study.

Question 5

What was the sample used?

Answer 5

A family from the Netherlands, on which 5 males were affected by borderline mental retardation and abnormal behaviour. They were convicted of arson, attempted rape and exhibitionism.

Question 6

How was data collected?

Answer 6

Urine samples were collected over a 24hr period.

Question 7

What did they find? (4 points)

Answer 7

• They found a disturbed metabolism associated with a deficit of the enzyme MAOA.
• A mutation was identified in the X chromosome responsible for MAOA production in each of the 5 males.
• MAOA regulates our serotonin levels, thus regulating our anger, aggression and inhibits inappropriate behaviours.
• Impaired serotonin metabolism disrupts the neuro-chemical activity, this imbalance is linked with aggressive behaviour and failure to control aggression leading to criminality.

Question 8

How is this study determinist?

Answer 8

It suggests that our criminality is determined by our genetics, whether we have an MAOA faulty gene.

Question 9

How is this study reductionist?

Answer 9

Assumes that aggressive criminal behaviour is due to an impaired serotonin metabolism, ignoring other factors such as social and cognitive.

Question 10

How is the study reliable?

Answer 10

• It is replicable

- It uses an objective and scientific measure of serotonin ( via urine samples)

Question 11

How does it support the nature side of the nature versus nurture argument?

Answer 11

It suggests that nature has a greater influence on our behaviour as genes are responsible.

Question 12

How is the study low in generalizability?

Answer 12

It is a case study.

Question 13

Name all 5 evaluative points.

Answer 13

1. Determinism
2. Reductionism
3. Reliability
4. Low generalizability
5. Nature versus Nurture