brain structures are an explanation for aggression

• o   The brain is a source of conscious awareness and where decision making takes place.

  o   It is divided into 2 hemispheres joined by the corpus collosum.

  o   Left hemisphere controls the right side of our body and the right hemispheres controls the left side of our body.

  o   The cortex is divided into 4 lobes which each control specific behaviours.

  o   Frontal lobe – voluntary movement and expressive language

  o   Temporal lobe – location for the auditory ability.
• o   Prefrontal cortex – influential in governing social interaction and regulation of behaviour. The ability to delay gratification of an impulse is associated with this area. Damage to this area often leads to problems with anger management, irritability, and impulse control.
• o   Hypothalamus – maintains homeostasis through the regulation of hormones, including those that regulate sexual function. This is linked to aggressive behaviour in males via the production of testosterone.
• o   Amygdala – centre for emotions, emotional behaviour, and motivation. It integrates internal and external stimuli. The prefrontal cortex also connects to the amygdala and it is this connection that may lead to the expression of aggression.
• A strength is that there’s evidence to support that different part of the brains have different functions e.g., damage to the amygdala would make it harder for a person to respond in a socially acceptable way to threat and causing a lack of fear of consequences. In Raines study, murderers showed asymmetrical activity in the amygdala, there was higher levels of activity in NGRIs compared to the controls. This is a strength as there were differences between those who are aggressive and those who aren’t therefore the amygdala must correlate to aggression.
• [strength] However, in Pardini’s experiment, he found that there was a negative correlation in aggression and amygdala volumes which questions whether aggression is based on the function of the amygdala or the size.
• A weakness is that research into brain areas is correlational as we cannot ethically conduct experiments on humans to aggravate the aggression levels. Raine could not purposely make the participants aggressive so he used already aggressive people which cannot show cause and effect. This is a weakness as it is not possible to conclude that brain structure is the only explanation of aggression as hormones, evolution and other factors may also play a part.
• [weakness] However, animal studies have shown some causality, damaging the amygdala of animals causes them to be less aggressive. Animals are also mammals and therefore have the brain structure as humans suggesting that the amygdala does produce aggression. However, this again links to the fact that aggression might be liked to the size as animals more commonly have relatively smaller brains.