Neural and hormonal influences Flashcards
What is the limbic system?
A system of subcortical structures associated with emotional behaviour
What are the 2 key structures of the limbic system in aggression?
The amygdala and hippocampus
What is the role of the amygdala?
Evaluating the emotional importance of sensory information and organising an appropriate response
What happens if parts of the amygdala are electrically stimulated?
It produces an aggression response
What happens if parts of the amygdala are removed?
No aggression is produced in response to the same stimuli
In the monkey amygdala study, what did they find?
When the amygdala was destroyed, the monkey lost its dominant place in its social group
What is the role of the hippocampus?
Forms long-term memories
How is the hippocampus associated with aggression?
It allows us to compare current threats with similar past experiences
Why can impaired hippocampus function lead to inappropriate responses to sensory stimuli?
It prevents the nervous system from putting things into a relevant and meaningful context
What effect does serotonin have on the brain?
A calming effect
What levels of serotonin are associated with aggressive behaviour?
Low levels
What effect does serotonin have on the amygdala?
It inhibits it from firing
What is testosterone?
A hormone that produces secondary sexual characteristics in males
When does testosterone peak in males?
Young adulthood
What happens to males when testosterone is artificially lowered/removed?
They are less aggressive
At what age is male-on-male aggression mostly seen?
Young adulthood
What are the 4 AO3 points for neural and hormonal influences on aggression?
1) Evidence for the role of the amygdala
2) Evidence for the role of the hippocampus
3) Inconsistent evidence for the role of testosterone
4) Evidence for serotonin deficiency hypothesis
What did one study find about amygdala volume?
Lower amygdala volume can be a predictor of severe and persistent aggression
In the study looking at the relationship between amygdala volume and aggression, what type of study was it?
Longitudinal study
In the study looking at the relationship between amygdala volume and aggression, at what age did the men have MRI scans?
26
In the study looking at the relationship between amygdala volume and aggression, how many men had MRI scans?
56
In the study looking at the relationship between amygdala volume and aggression, what happened once confounding variables were controlled for?
The relationship between amygdala volume and aggression prevailed
In the research supporting the role of the hippocampus on aggression, who were studied?
Violent offenders
In the research supporting the role of the hippocampus on aggression, what were the 2 groups?
Successful psychopaths and unsuccessful psychopaths
In the research supporting the role of the hippocampus on aggression, how were successful psychopaths characterised?
Evaded the law + cold and calculating
In the research supporting the role of the hippocampus on aggression, how were the unsuccessful psychopaths characterised?
Those who were convicted + impulsive
In the research supporting the role of the hippocampus on aggression, what did MRI scans find about the unsuccessful psychopaths?
They had asymmetries in their hippocampi
Why is their inconsistent evidence for the role of testosterone in aggression?
Some studies have found a positive correlation between testosterone and aggression, but other studies have found no such relationship
What did the study of prison inmates find about testosterone?
Positive correlations between testosterone and self-reported aggression levels were found
What did the study about violent inmates and testosterone find?
There was no correlation between testosterone levels and actual violent behaviour in male inmates
In the meta-analysis that supports the serotonin deficiency hypothesis, how many studies were included?
175
In the meta-analysis that supports the serotonin deficiency hypothesis, how many participants were there in total?
Over 6500
In the meta-analysis that supports the serotonin deficiency hypothesis, what was found?
A small inverse relationship between serotonin levels and aggression
In the meta-analysis that supports the serotonin deficiency hypothesis, what was found to influence the magnitude of the relationship found? (3)
The methods used to assess serotonin functioning, the year of publication and whether the aggression was self-reported or not
