brain structure

Question 1

midbrain

Answer 1

• one brain area associated with aggression is the midbrain
• the midbrain contains an area called the periaqueductal grey matter (PAG) which links the amygdala and hypothalamus to the PFC.
• it has a role in coordinating and integrating behavioural responses to threat and pain
• lesions and damage to the midbrain in rats that had just recently given birth showed an increase in aggression when faced with threat

Question 2

amygdala

Answer 2

• the amygdala is the centre of emotions, emotional behaviour and motivation
• it is responsible for the fight or flight response, meaning when stimulated aggression can occur
• it appears to function in tandem with the orbitofrontal cortex to cause aggression
• and it plays a role in cognitive functions such as self control and impulse regulation
• those with psychiatric illnesses have reduced activity in the orbitofrontal cortex

Question 3

hypothalamus

Answer 3

• the hypothalamus is associated with aggression
• it plays a role in homeostasis (maintaining a constant internal environment in the body in response to external stimuli like temperature) through regulation of hormones like testosterone
• dysfunction in this area may increase testosterone and therefore aggression.

Question 4

prefrontal cortex

Answer 4

• plays a role in social interaction and regulation of behaviour
• the ability to delay gratification is associated with the pfc
• damage to this area can lead to anger problems, irritability and impulsivity

Question 5

strengths

Answer 5

supporting evidence from raine et al who found that murderers pleading not guilty by reason of insanity had higher levels of activity in the right amygdala that the control group (0.88 vs 0.83). therefore, showing that their is a link between the limbic system and aggression as the murderers had abnormal levels of activity in the amygdala.

supporting evidence from phineas gage’s case study, who had a metal pole struck through his frontal lobe which led to personality changes like anger problems, irritability and aggression. His family described him as fitful and grossly profane. therefore, showing how damage to the prefrontal cortex can lead to irritability and impulsivity that leads to aggression.

Question 6

weaknesses

Answer 6

The brain structure theory of aggression lacks generalisability as most of the studies conducted are animal research. For example, lesions and damages in the PAG of rats that had just given birth were looked at. Rats are not like humans as they have less complex brain structures. Humans have higher order thinking/ cognition and more developed PFC’s. We also have better problem solving skills than rats. Therefore, the results of increased aggression in rats due to damage of the PAG in the midbrain are not representative of human aggression.

Question 7

application

Question 8

weakness of phineas gage

Answer 8

This is a case study conducted on one male ppt who suffered a unique injury and case. There may have been something unusual about Phineas Gage that caused him to start acting differently. It doesn’t take into account individual differences and how others may have responded differently to having their PFC damaged. Therefore, the sample is not representative of how damage to brain structures like the PFC cause aggression in a wider population, so the theory is not generalisable to wider society.

Question 9

alternative theory

Answer 9

an alternative theory would be SLT which suggests aggression is caused due to imitation of role models like your parents, if you watch your parents be verbally or physically abusive then you are more likely to do the same. For example, Bandura found that children were likely to copy a role model after observing them hit a bobo doll. Therefore, showing that damage to brain structures like the midbrain, amygdala, hypothalamus and PFC may not be the sole cause of aggression, making the theory reductionist and a narrow explanation.

Question 10

application

Answer 10

high application to society as if we know damage to brain structures can cause aggression, we can pre-screen people to check if they have these abnormalities. Therefore, they can be given early intervention and treatments like anger managment programmes (CBT) to prevent them from going on to commit crimes.