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AQA A-Level Psychology Year 2 > Aggression > Flashcards

Flashcards in Aggression Deck (34)
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what are the neural mechanisms in aggression?

the limbic system and serotonin


what is the limbic system?

connects the brain stem and the cortex

has the amygdala

controls a range of emotional behaviours


what is the role of the amygdala?

quickly evaluates the emotional importance of sensory information and promoting an appropriate response


what did Pardini et al find

participants with smaller amygdalas showed higher levels of aggression


what did ervin study and find?

case study of female patient

electrically stimulated her amygdala

she became very angry and flung herself at a wall

atypical female


what is kluver and bucy find?

that destroying the amygdala in aggressive monkeys, resulted in less aggressive behaviour


what study was done using fmri scans on the limbic system?

ps had their brains scanned while playing a game where they could reject or accept an offer of money. heightened activity in the amygdala when they rejected money because they thought it was unfair


What also operates with the amygdala?

the orbitofrontal cortex


what does the orbiofrontal cortex do?

regulates emotional responses driven by the amygdala

damage results impulsivity and loss of control


What did Raine et al find?

investigated brain activity in 42 murderers using PET scans.

abnormal activity in the amygdala and reduced glucose metabolism in the orbitofrontal cortex


What is serotonin?

a neurotransmitter involved in the communication of impulses between neurons


What are normal levels of serotonin associated with?

greater behavioural control and it typically inhibits the firing of the amygdala system


what are low levels of serotonin associated with?

low behavioural control, impulsivity and aggression


what is tryptophan?

increases serotonin levels in the brain


What did Rayleigh study and find?

gave different diets to monkeys

the monkeys who diet was high in tryptophan showed decreased levels of aggression


what did Passamonti find and study?

manipulated tryptophan levels in participants diets

ps given questionnaire to asses their aggressive tendencies

fmri scans to measure reaction to facial expressions

on low serotonin days, communication was weaker


practical application of research into serotonin

diets to easier serotonin levels such as tryptophan could be given to juvenile delinquents in order to calm aggressive tendencies


How have high levels of serotonin been associated with aggression?

dukes et al found a relationship


What is testosterone?

an androgen secreted by the testes.



Research for (mice)

Wagner- catstrated mice and aggression reduced, later injected them with testosterone which re-established their aggression.



Research for (species)

Increasing testosterone caused greater aggressive behaviour in several species and reducing it had the opposite effect.



Research for (prisoners)

Dabbs- measured testosterone levels in 692 adult male prisoners, higher levels were found in violent offedners compared to non-violent offenders.

Found a similar effect in women prisoners.



Research against (Dual-hormone hypothesis)

high levels of testosterone lead to aggresive behaviour when cortisol levels are low.


Evaluation of testosterone

Aggression or dominance?

Studies show that testosterone doesnt necessarily increase aggression but increases status-seeking behaviour, which is not intended to cause harm.


What does genetic theory say about aggression?

that genes are the cuase of aggressive behaviour.


Genetic factors

Research for (mice)

Lab selective breeding study.

Isolated a group of mice in order to identify mice more prone to aggression.

interbred the aggressive mice, after 19 generations, rates of aggression were 10x higher than in the controls.

the aggressive mice had heavier testes and forebrains and altered levels of serotonin and noradrenaline.


Genetic factors

Research for (twin and adoption studies)

Coccaro used a questionnaire to measure hostility in male participants.

they found concordance rate of 50% for MZ twins and 19% for DZ twins.

Rhee and Waldman- meta-analysis of adoption studies, found genetic influences account for 41% of the variation of aggression.


Genetic factors

The MAOA Gene

This gene is responsible for regulating the enzyme MAOA, which breaks down the neurotransmitters serotonin, noradrenaline and dopamine. This allows neurons to commincate more effectively.


Genetic factors

What does reserch suggest about the MAOA Gene

that the MAOA-L version predisposes a peron to violence.


Genetic Factors

What did Brunner research?(Dutch family)

Male members of this family had been particulary aggressive, the males were found to have the rare mutated version of the MAOA gene.