Neural Ans Hormonal Mechanisms

Question 1

What role does the limbic system play in aggression? And where is it found?

Answer 1

• central part of the brain

- limbic system processes emotional responses

Question 2

What part of the brain moderates the level of testosterone in response to trigger from the environment?

Answer 2

The pre - frontal Cortex

• more specifically the amygdala.

Question 3

Name a piece of research to support the limbic system?and what did they find?

Answer 3

• raine (1997)
• scanned 41 murders and 41 controlled participants.
• using pet scans
• found malfunction in some of the murders limbic systems linking the limbic system to aggressive behaviour.

Question 4

What is likely to happen if the amygdala is damaged in anyway?

Answer 4

• the person will become more aggressive.

Question 5

What is serotonin?

Answer 5

• serotonin is a neurotransmitter that regulates the feeling of well - being.

Question 6

What is an example of drug that lowers serotonin? What does it do and what are the problems?

Answer 6

• Prozac.
• it reduces the serotonin levels
• the problem with it is it can make you feel depressed and feel more aggressive. In some cases.

Question 7

What is the problem with research on serotonin?

Answer 7

• the research is unclear suggesting both lowering the serotonin levels and increasing then leads to aggressive behaviour.
• unclear results.

Question 8

What is the CURRENT feeling around what serotonin does?

Answer 8

• Crockett and Passamonti (2011)
• found that lower serotonin levels = less control of the frontal Cortex.
• less serotonin = less control of emotional response.
• Meaning the lower the serotonin levels the more aggressive you will be.

Question 9

Name research into serotonin in regards to animals? And what did they find?

Answer 9

• Huber (1997)
• increased serotonin in crayfish and times how much longer they continued to fight.
• he compared crayfish will serotonin VS crayfish with normal levels of serotonin.
• found that crayfish with added serotonin fought for longer.
• however Huber was unsure whether they fought for longer due to increase aggression or natural response unable to mediate the trigger.

Question 10

Name a piece of research into serotonin in regards to humans. And what did they find?

Answer 10

Cherek (1996)

• found men who take drugs to increase serotonin had lower levels of aggression.
• suggesting a link. But a weak link.

Question 11

Give 2 evaluative points.

Answer 11

❌ extrapolation issues - research mainly done on animals because it is too unethical to increase aggression in humans because of stress and anxiety. Hard to generalise to humans also.

❌ Biochemistry is very deterministic. This suggests people could be over ridden without there control. This causes problems for the legal system as they can’t blame any criminals if they couldn’t control what they had done wrong.

Question 12

What type of hormone is testosterone?

Answer 12

It is an androgen

• (male hormone)

Question 13

What is the enzyme associated with aggression and what does it do? And where is it found?

Answer 13

• Aromatase enzyme
• it is found in the limbic region (amygdala)
• Aromatase metabolises testosterone in the brain to create an adequate response to an environmental trigger.

Question 14

What happens if Aromatase is reduced?

Answer 14

• if reduced there is not enough enzyme to metabolise the testosterone so there will a smaller effect and response to emotions experienced.
• this means less aggression experienced

Question 15

What do the levels of testosterone also affect?

Answer 15

• the orbital frontal cortex
• high testosterone = decreased activity in the orbital frontal cortex.
• testosterone lowers serotonin levels = less serotonin = more aggressive
• testosterone isn’t isolated it affects other bio chemicals.

Question 16

What is research into testosterone?

Answer 16

Conor + Levine (1969)

• used rats and castrated them at birth to see if they were aggressive. They were not. = passive. Even after testosterone injections had not aggression.
• then castrated rats who were fully developed. They were passive but returned to their former aggression when injected with testosterone.
• showing testosterone is sensitive to the development process

Question 17

Name 2 evaluative points on the research on testosterone in aggression.

Answer 17

❌ Extrapolation issues - use of rats hard to generalise due to different physiological aspects. Humans very complex to why we become aggressive.

❌ certain brain structures are different in animals. For example. Cingulate gyrus an area in the brain in cats and dogs which is irritable and linked with aggression, in monkeys it’s associated with fear.

Question 18

What do genes determine in regards to testosterone and aggression?

Answer 18

• determine levels of testosterone and the speed of which it can be metabolised.
• also determines number of receptors and how sensitive they are.

Question 19

What types of study do genetic factor experiments use?

Answer 19

• twin studies/ adoption studies

- also use controlled studies using bred animals for research to reduce social behaviour and imitation.

Question 20

What is key about the genotype and phenotype?

Answer 20

• the genotype may be aggressive but the phenotype prevents this if nothing terrible has happened to the person before.

Question 21

How does the MAOA gene affect the body?

Answer 21

• it affects the levels of neurotransmitters.

Question 22

What is MAOA and what does it it do?

Answer 22

MAOA is an enzyme that breaks down neurotransmitters such as dopamine, noradrenaline and serotonin.

• controlled by the MAOA gene.

Question 23

What are the two types of MAOA gene? What is the difference?

Answer 23

MAOA - H

MAOA - L

H has a high amount of enzyme

L has a low amount of enzyme

Question 24

What fraction of men have the MAOA -L gene?

Answer 24

1/3 of men in western areas.

Question 25

What is key for the aggressive behaviour of someone with the MOAO - L for them to become aggressive?

Answer 25

• abused as a child can stimulate the aggressive behaviour from the MAOA -L gene.
• more likely to commit a violent crime.

Question 26

Name a piece of research into the MAOA gene.

Answer 26

Moffit (1992)

Studied 442 New Zealand men.

From birth to 26 years old

Kept a record if the MAOA - L gene was present

• found ones who suffered abuse as a child and had the MAOA - L gene were 9x more likely to commit an aggressive crime.

Question 27

Give two evaluative points in regards to the MAOA gene in aggression.

Answer 27

❌ Android centric and lacks ecological validity. Only 1/3 of men are accounted for. 2/3 of men and all the women don’t have the gene and are not accounted for. So can’t be generalised to everyone.

✅ helps to explain evolutionary theory as many people who have the gene are thought to take more risks and stand out more, making them more attractive and find reproducing easier.