Agression Flashcards
What are the two neural influences in aggression?
- The limbic system
- Serotonin
What is the limbic system?
A system of sub cortical structures in the brain associated with regulating emotional behaviour
What key structures make up the limbic system?
- Amygdala
- Hippocampus
- Hypothalamus
What does the amygdala do?
Evaluates emotional importance of sensory information in the environment and prompting an appropriate response
How is the amygdala implicated in aggression?
Increased activity of the amygdala = higher aggression
What is serotonin?
A neurotransmitter which has inhibitory, calming effects in the brain
How is serotonin implicated in aggression?
Reduced levels= removal of inhibitory effect leading to more impulsive and aggressive behaviour
What is the hormonal influence in aggression
Testosterone
What is the name do the researcher who studies the role of the amygdala in aggression
Gospic
What was Gospics procedure
- ptsps Were given a range of scenarios in a game called ultimatum game and their brains are scanned by fMRI
What did Gospic find
He found that when ptsps rejected unfair offers (aggressive reaction) scans showed a heightened response by the amygdala
- when ptsps were given a benzodiazepine drug (reduces arousal if autonomic system) found that
1: the number of rejections were halved
2. Decreased activity of the amygdala
Who studies the effect on serotonin on aggression
Mann et al
What was Mann et als procedure
Have 35 healthy ptsps dexfenfluramine (reduces serotonin levels)
What did Mann et al find
Found that this drug treatment in makes (not females ) was associate with an increase in hostility and aggression scores in questionnaires
Which two people studied the effect of testosterone on aggression
- Dolan et al
- Dabbs et al
What did Dolan et al find
Found a strong positive correlation between testosterone levels and aggressive behaviour in a sample of 60 offenders in the Uk
What did Dabbs et al do and find
Measured salivary testosterone in violent and non violent criminals
And he found that those with highest testosterone levels had a history of primarily violent crimes Whereas those with lowest levels had committed non violent crimes
What is the MAO-A
An enzyme that regulates the metabolism of serotonin in the brain
What is the MAOA gene
The gene responsible for the activity of the enzyme MAOA in the brain.
What specific gene allele is associated with aggression
MAOA-L
What study reveals the influence of the MAOA gene on aggression
Brunner et al
What did brunner et al find
He found the males in a Dutch family who had a history of impulsively aggressive behaviour had abnormally low levels of MAOA and the low activity version of the MAOA gene
What is the difference between monozygotic and dizygotic twins
Mz scare 100% of DNA whereas DZ twins share 50% of their genes
Which twin study reveals the influence of genes on aggression
Coccaro et al
what did Coccaro et al find?
he found that the concordance rate of physical assault for DZ twins is 19%, for MZ twins is 50%
the concordance rate for verbal aggression in MZ twins is 28% and for DZ twins 7%
which adoption study reveals the influence of genes in aggression?
hatchings and medrick