neural and hormonal mechanisms in aggression

what are the two types of aggression?

• reactive - response to a perceived threat

• proactive - response in anticipation of a reward

what type of aggression does the Papez-Maclean limbic theory explain?

reactive aggression

the limbic system is believed to be …

hierarchical, with signals being passed from lower systems to higher systems in the prefrontal cortex

what is the role of the prefrontal cortex? (1)

controls decision making and regulation of emotions

where is the orbitofrontal cortex located and what is its role? (2)

• located in the frontal cortex

• linked to self-control, inhibitions, and reward in decision making

how is the orbitofrontal cortex linked to aggression? (3)

• reduced serotonin levels in the orbitofrontal cortex can reduce self-control

• person can’t control their responses in a usual way, and becomes aggressive easily

• can’t anticipate risk and impulsively engage in aggressive behaviour

what is the role of the amygdala? (1)

regulating fear an aggression as helps detects threats and trigger the fight or flight response

what is the effect of low serotonin levels in the amygdala? (2)

• serotonin works on frontal areas of bran to inhibit firing of amygdala

• amygdala is worse at regulating aggressive responses, resulting in higher levels of aggression

how is the hypothalamus linked to aggression? (2)

• regulates the the autonomic nervous system, which regulates responses to emotional circumstances

• damage to this area can result in an inappropriate aggressive response to a perceived threat

how is testosterone linked to aggression? (1)

it increases neural activity in the amygdala and reduces how well the amygdala communicates with the orbitofrontal cortex

what supporting research is there for the role of the limbic system?

• MRI scans were used to investigate the relationship between amygdala behaviour and aggressive behaviour

• 19 scans of violent male criminals were taken and compared with 20 normal control subjects

• the volume was found to be bigger, this supports the role of the amygdala and limbic system

how is the explanation of neural and hormonal mechanisms in aggression reductionist?

• doesn’t consider the effect of all brain areas, genes, or the environment in influencing aggression

• there could be inherited genes that could increase someone’s levels of aggression, or highly stressful environment could increase aggression

• therefore isn’t a full explanation; limited

what is the issue with the supporting research for the role of the limbic system having age bias?

• the findings can’t be generalised to women

• so we can’t understand how brain areas are linked to aggression in women

• this decreases ecological validity

what is the issue with supporting research being correlational?

• just because research found when serotonin levels were reduced, there were higher levels of aggression

• doesn’t mean it is (only) serotonin causing this - could be other neurotransmitters that haven’t yet been researched that influence aggression

• this decreases validity of explanation