Aggression Flashcards
1
Q
- What is the limbic system?
A
- Subcortial structures in the brain (including hypothalamus and amygdala) thought to be closely involved in regulating emotional behaviour including aggression
2
Q
- What was James Papez and Paul Maclean’s role in terms of the existence if the lambic system?
A
- The first attempt to link limbic structures to emotional behaviours such as aggression was by JAMES PAPEZ and later revised PAUL MACLEAN
3
Q
- What is the limbic system said to be made up of?
A
- Cingulate gyrus
- Septal area
- hypothalamus
- fornix
- amygdala
- part of hippocampus and thalamus
4
Q
- State and define the most important role in the limbic system:
A
- The most important structure by far is the AMYGDALA
- This has a key role in humans and non human animals in how an organism assesses and responds to environmental threats and challenges
- The reactivity if the amygdala has proven to be an important predictor of aggressive behaviour
5
Q
- What was Katarina Gospic’s study?
A
- Used a well established lab method of assessing aggressive behaviour= Ultimatum Game
- Featured 2 players
- Proposer offers to split money in a certain way with responder
- If responder accepts, the money is split as proposed
- if responder rejects offer, both receive nothing
- Participants in this study played as responders while having their brains scanned by fMRI- which highlights activity in different areas of the brain
6
Q
- What were the findings in Katharine Gospic’s study?
A
- Researchers found that when responders rejected unfair offers (aggressive reaction to social provocation) scans revealed a fast and heightened response from the amygdala
- They also found that a benzodiazepine drug (reduces arousal of ANS) taken before the game had 2 effects on responses to unfair offers- it halved the number of rejections (i.e. reduced aggression) and decreased amygdala activity
- This is strong evidence of an association between reactive aggression and amygdala activity
7
Q
- Define serotonin:
A
- A neurotransmitter with widespread inhibitory effects throughout the brain; it slows down and damps neural activity
- It has a key role in aggressive behaviour
8
Q
- What is normal levels of serotonin associated with?
A
- Normal levels of serotonin in the orbitofrontal cortex = linked with reduced firing of neurons which is associated with a greater degree of behavioural self-control
9
Q
- What is decreased levels of serotonin associated with?
A
- Decreased serotonin may well disturb this mechanism, reducing self-control and leading to an increase in impulsive behaviour including aggression
10
Q
- What was Matti Virkkunen’s study?
A
- Compared levels of serotonin breakdown product (metabolite called 5-HIAA) in cerebrospinal fluid of violent impulsive and violent non-impulsive offenders
11
Q
- What were the findings in Matti Virkkunen’s study?
A
- The levels were significantly lower in impulsive offenders and they also suffered from sleep irregularities
- This is significant because serotonin regulates sleep patterns
- Disturbance of this pattern strongly implies some disruption of serotonin functioning, further supporting the role of serotonin in reactive aggression
12
Q
- What is a hormonal mechanism in aggression?
A
- Testosterone
13
Q
- Define testosterone:
A
- A hormone from the androgen group and is mainly produced in the male testes (and in smaller amounts in the female ovaries)
- Associated with aggressiveness
- responsible for development of masculine features
- has a role in regulating social behaviour via its influence on certain areas of the brain implicated in aggression
14
Q
- What have animal studies suggested (Giammanco)?
A
- Animal studies have demonstrated that experimental increases in testosterone are related to greater aggressive behaviour in several species
15
Q
- What was Mairead Dolan’s study and findings?
A
- Some evidence from a similar association in humans come from studies of prison populations ,e.g. violent offenders.
- Dolan found a positive correlation between testosterone levels and aggressive behaviours in a sample of 60 male offenders in the UK Max security hospitals
- These men mostly suffered from personality disorders (e.g. psychopathy) and had histories of impulsively violent behaviour
16
Q
- Evaluation- Neural And Hormonal Mechanisms In Aggression:
A
- Role of other brain structures
- Effects of drugs on serotonin
- Explaining the role of testosterone
- Other hormones
17
Q
- Define genetic factors:
A
- Genes consist of DNA strands
- DNA produces ‘instructions’ for general physical features of an organism (e.g. eye colour, height) and also specific physical features (e.g. neurotransmitter levels and size of brain structures)
- These may impact on psychological features (e.g. intelligence and mental disorder)
- Genes are transmitted from parents to offspring, i.e. inherited
18
Q
- Twin studies- Emilio Coccaro:
A
- Several twin studies have suggested that heritability accounts about 50% of variance in aggressive behaviour
- E.g. Coccaro studied adult male MZ twins and DZ twins
- MZ twins share 100% of their genes but DZ share only 50% (on average) - expect to find greater similarities in aggressive behaviour between MZ twins if aggression is mostly influenced by genetic factors
- both MZ and DZ twins are raised together in the same environment, but MZ twins have a greater degree of genetic similarity than DZs
- For aggressive behaviour = direct physical assault- concordance rates of 50% for MZ twins and 19% for DZ
- Verbal aggression = 28% (MZs) and 7% (DZs)
19
Q
- What do similarities in aggressive behaviour between an adopted child and their biological parents suggest?
A
- Suggests that genetic influences are operating
20
Q
- What do similarities with the adopted parents suggest?
A
- suggests that environmental influences are operating
21
Q
- What was Soo Rhee and Irwin Waldman’s study?
A
- They carried out a meta-analysis of adoption studies of direct aggression and antisocial behaviour, a prominent feature of which is aggressive behaviour
22
Q
- What were the findings of Soo Rhee and Irwin Walding’s study?
A
- They found that genetic influences account for 41% variance in aggression
- more or less in line with findings from twin studies
23
Q
- What is the MAOA gene?
A
- The gene responsible for the activity of the enzyme monoamine oxidase in the brain
- The low activity variant of the gene is closely associated with aggressive behaviour
24
Q
- What is the role of the monoamine oxidase A enzyme?
A
- To ‘mop up’ neurotransmitters in the brain after a nerve impulse has been transmitted from one neuron to another
- It does this by breaking down the neurotransmitter- especially serotonin- into constituent chemicals to be recycled or excreted (process called catabolism)
- The production of this enzyme is determined by the MAOA gene
25
Q
- What happens when there’s a dysfunction in the operation of the MAOA gene?
A
- May lead to abnormal activity of th MAOA enzyme, which in turn affects levels of serotonin in the brain
26
Q
- What does the variant of the MAOA gene (‘warrior gene’) lead to?
A
- Leads to low MAOA activity in areas of the brain and has been associated with various forms of aggressive behaviour