Aggression- Neural and hormonal explanations Flashcards
Define the limbic system
A network of structures in the brain thought to be involved moderating aggression
What is the Amygdala?
The area of the brain that processes emotions
What is the role of the hypothalamus?
Sends and receives hormones related to emotions
What is serotonin?
A neurotransmitter linked with regulating mood
What does serotonin do in relation to aggression?
-It inhibits the amygdala which controls fear, anger and other emotional responses
-Decreased levels of serotonin remove the inhibitory effect so individuals have less impulse control and more aggressive behaviour
What does normal functioning of of serotonin do?
Exerts a calming and inhibitory effect
What did Mann et al find?
-Dexfenfluramine in males which depletes serotonin increases hostility and aggression
Is the amygdala proven to be an important predictor of aggressive behaviour?
Yes
What is testosterone?
The male sex hormone, androgen responsible for the development of masculine features
Why does testosterone relate to aggression?
It regulates social behaviour (increased levels are thought to be related to increased levels of aggression
What did Dolan et al find?
-A positive correlation between testosterone levels and aggression
-60 male offenders in UK maximum security hospitals
-Most offenders suffered from personality disorders and had histories of impulsive, violent behaviour
-Reduced reliability
Give an evaluation point for the amygdala
P: Evidence for the role of the amygdala in aggression
E: Padini et al found that reduced amygdala volume can predict the development of severe and persistent aggression
E: Longitudinal study of male participants from childhood to adulthood, 56 participants had a history of violence and were given a brain MRI at 26
E: Results showed that participants with lower amygdala volumes displayed higher levels of violence and aggression (this relationship stayed the same even after confounding variables were controlled
L: Suggests the amygdala plays an important role in assessing the emotional importance of sensory information and that lower amygdala volume effects this and violent responses are more likely
Give an evaluation point for testosterone
P; Inconsistent evidence
E: despite many studies showing a positive correlation between testosterone and aggression there are some studies which cannot find a relationship
E:Positive correlations have been found in self report studies from prison inmates (Albert et al) and Olwevs study between tetsosterone levels and the liklihood of responding agressivley to provocation
E: hwoever, no correlation was found between testosterone levels and catual violent behaviour between inmates
L: This not only shows that slef report studies can be unreliable but that it remains unclear whether there is a coreelation or not, correlation does not mean causation either
Give an evaluation point for serotonin
P: Research support for the involvement of serotonin in aggression
E: Duke et al carried out a meta analysis of 175 studies involving 6500 participants
E: This analysis found a small negative correlation between serotonin levels and aggression, anger and hostility. The strength (magnitude) of the relationship varied with the methods used to assess this and was highest with self reporting
-This shows that there is a complex relationship
L- The use of SSRIs (regulate and promote serotonin levels have been shown to reduce aggression
Give an evaluation for Gospic et al
P: There is an association between reactive (impulsive0 agression) and amygdala actvity
e: Gospic et al used a lab method called the ultimatum game to asses agressive behaviour which involved 2 players (prposer and responder) where money can be split however the proposer wants, if the responder accepts the money is plitas proposed but if it is rejected they both reveive nothing
E; this do this while having their brains scanned using fMRI which showed that rejection of unfair offers produced a fast and heightened response from the amygdala
L: However in a variation it was found that when a benzodiazepine drug (reduces arousal of ANS) as taken it had 2 effects on unfair offers, it 1/2 rejections, reduced aggression, decreases activity the amygdala which shows it does influence aggression
