1 - Neural + Hormonal Mechanisms In Aggression

Question 1

What are the 3 main neural + hormonal factors that must be learnt?

Answer 1

1) Limbic system
2) Serotonin
3) Testosterone

Question 2

Define aggression

Answer 2

An act carried out with the intention to harm another person physically or psychologically

Question 3

What is hostile aggression?

Answer 3

‘Affective aggression’ - driven by anger + emotion (e.g. murder)

Question 4

What is instrumental aggression?

Answer 4

‘Pre-meditated aggression’ - calmer, more emotionally detached aggression (e.g. in sport)

Question 5

What are the 2 neural factors related to aggression?

Answer 5

1) Limbic system

2) Serotonin

Question 6

What is the limbic system?

Answer 6

A subcortical structure in the brain, thought to be involved with the regulation of primitive functions, including emotions + aggressive

Question 7

List the components that make up the limbic system

Answer 7

• Cingulate gyrus
• Septal area
• Hypothalamus
• Fornix
• Amygdala
• Parts of hippocampus + thalamus

Question 8

What is the main part of the limbic system we look at in relation to aggression?

Answer 8

Amygdala

Question 9

Which 2 people linked the limbic system to emotional behaviours including aggression?

Answer 9

Papez + Maclean

Question 10

What is the role of the amygdala?

Answer 10

Responds to threats + challenges in the environment

Question 11

How does the limbic system impact aggression?

Answer 11

The more reactive the amygdala (part of the limbic system), the more aggressive a person is

Question 12

Name + outline the research done to support the role of the limbic system (amygdala) in aggression?

Answer 12

Gospic et al

• Ultimatum Game
• Ppts’ brain activity scanned using an fMRI
• fMRI showed a fast, heightened reaction in the amygdala when ppts given an unfair offer (provoked) + respond aggressively by rejecting it
• When given benzodiazepine drugs (reduce amygdala activity) rate of rejection dropped (less aggressive)
• Supports role of amygdala in aggression

Question 13

What is serotonin?

Answer 13

A neurotransmitter with widespread inhibitory effects throughout the brain

Question 14

What does it mean for a neurotransmitter to have ‘inhibitory effects’?

Answer 14

Neurones fire less

Question 15

How do normal serotonin levels lead to behavioural self-control?

Answer 15

Normal serotonin levels -> Inhibitory effects in the orbitofrontal cortex -> Good self-control

Question 16

How does serotonin impact aggression?

Answer 16

Low levels of serotonin lead to more aggressive + impulsive behaviour

Question 17

How does low serotonin lead to more aggression?

Answer 17

Decreased serotonin disrupts the inhibitory effects in the orbitofrontal cortex -> less behavioural self-control -> more aggressive, impulsive behaviour

Question 18

Name + outline the research done to support the role of serotonin in aggression?

Answer 18

Berman et al

• Lab study
• Group 1: given SSRI paroxetine (higher serotonin)
• Group 2: given placebo (lower serotonin)
• Groups provoked + able to shock each other
• Group 1 gave fewer, less intense shocks (high serotonin - less aggressive)

Question 19

Give 3 evaluation points for the role of neural mechanisms in aggression

Answer 19

GOOD
Drugs (SSRIs) support
- Berman’s research using SSRIs supports role of serotonin
- Using SSRIs has a practical application as a cheap + effective treatment for high aggression

BAD
Other brain structures may also be important
- Limbic system isn’t only important brain structure
- Orbitofrontal cortex is also involved in impulse regulation + inhibiting aggression
- Coccaro et al found less activity here led to greater aggression
- So, the neural explanation may be too simplistic currently

Deterministic

• Suggests aggression is pre-determined by neural factors
• Pessimistic view + acts as an alibi for aggressive crimes (negative implications for the legal system)

Question 20

What is the main hormonal factor we learn in relation to aggression?

Answer 20

Testosterone

Question 21

What is the extra hormonal factor that we learn in relation to aggression?

Answer 21

Progesterone

Question 22

What is testosterone?

Answer 22

A hormone from the androgen group produced 10-40x more in men (in testes) than in women (in ovaries)

Question 23

How does testosterone impact aggression?

Answer 23

High testosterone leads to high aggression

Question 24

Name + outline the human research done to support the role of testosterone in aggression?

Answer 24

Dolan et al

• Correlational study
• Looked at 60 male offenders + their testosterone levels
• Found positive correlation between testosterone + aggression

Question 25

Name + outline the animal research done to support the role of testosterone in aggression?

Answer 25

Wagner - Lab - Castrated mice (stopping testosterone production) - Castrated mice were less aggressive (less biting) - If testosterone was re-injected, aggression (biting) increased, showing cause + effect of the impact of testosterone on aggression

Question 26

What is progesterone?

Answer 26

Female ovarian hormone

Question 27

When is progesterone lowest?

Answer 27

During + just after menstruation

Question 28

How does progesterone impact aggression?

Answer 28

Low levels of progesterone lead to high aggression

Question 29

Does testosterone vary throughout the month?

Answer 29

No - some men just have higher testosterone

Question 30

Does progesterone vary throughout the month?

Answer 30

Yes - varies in relation to the menstrual cycle

Question 31

Name + outline the research done to support the role of progesterone in aggression?

Answer 31

Ziomkiewicz et al - Self report data on levels of aggression across menstrual cycle - Found negative correlation between levels of progesterone + aggressive behaviour

Question 32

Give 3 evaluation points for the hormonal mechanisms in aggression

Answer 32

GOOD Animal research support - Research support from multiple animal studies on role of hormones - E.g. Wagner (mice - testosterone) + Giammanco (meta analysis) - BUT: Issues - may be unethical (no consent + potentially harmful) BAD Alternative theory - Dual hormone hypothesis - Carre + Mehta said high testosterone only leads to aggression if cortisol levels are simultaneously low (because cortisol can block testosterone’s influence on aggression) - Testosterone’s current role may be too simplistic, as cortisol must also be considered Deterministic - Suggests aggression is pre-determine by hormonal factors - Pessimistic view + acts as an alibi for aggressive crimes (negative implications for the legal system)

Question 33

What is the dual hormone theory?

Answer 33

Idea that high testosterone only causes aggression if cortisol levels are low - because high cortisol has a blocking effect on testosterone

Question 34

What impact does cortisol have on testosterone?

Answer 34

A ‘blocking effect’ (blocking its ability to increase aggression)