Discuss the neural and hormonal explanations of aggression
Discuss the neural and/or hormonal mechanisms in aggression (8 marks + 16 marks)
Aggression is a behavior directed towards another intended to harm or injure. Neurotransmitters are chemicals that enable impulses in the brain to be transmitted from one area of the brain to another. There’s evidence that the neurotransmitters serotonin and dopamine are closely linked to aggressive behavior. Low levels of serotonin and high levels of dopamine have been associated with aggression in both animals and humans.
Low levels of serotonin are thought to reduce aggression as in a study by Delville 1997 found that drugs increasing the production of serotonin lead to reduced levels of aggression, suggesting that low levels of serotonin are linked to aggression. Raleigh et al 1991 who carried out research on vervet monkeys to support this. They found that monkeys fed on experimental diets that were high in tryptophan, which increases serotonin, exhibited decreased levels of aggression. The monkeys fed on diets low in tryptophan showed increased aggressive behaviour. This suggests that the difference in aggressive behaviour could be linked to serotonin levels. However Delville’s study is low on ecological validity as it is a lab experiment. Also Raleigh et al’s experiment is animal based it is difficult to generalize it to humans as we have different physiology to animals. Also both studies do not take in to account the evolutionary approach to aggression.
Dopamine also plays a role in aggression, although it is not as well established as the link between serotonin and aggression. Buitelaar 2003 claims that antipsychotics which reduce dopamine activity in the brain have been shown to reduce aggressive bahaviour in violent delinquents. However this is limited as a study shown by Coupiss and Kennedy 2008 who carried out research in mice and found that a reward pathway in the brain becomes engaged in response to aggressive behaviours and events, and that dopamine is involved as
Aggression is a behavior directed towards another intended to harm or injure. Neurotransmitters are chemicals that enable impulses in the brain to be transmitted from one area of the brain to another. There’s evidence that the neurotransmitters serotonin and dopamine are closely linked to aggressive behavior. Low levels of serotonin and high levels of dopamine have been associated with aggression in both animals and humans.
Low levels of serotonin are thought to reduce aggression as in a study by Delville 1997 found that drugs increasing the production of serotonin lead to reduced levels of aggression, suggesting that low levels of serotonin are linked to aggression. Raleigh et al 1991 who carried out research on vervet monkeys to support this. They found that monkeys fed on experimental diets that were high in tryptophan, which increases serotonin, exhibited decreased levels of aggression. The monkeys fed on diets low in tryptophan showed increased aggressive behaviour. This suggests that the difference in aggressive behaviour could be linked to serotonin levels. However Delville’s study is low on ecological validity as it is a lab experiment. Also Raleigh et al’s experiment is animal based it is difficult to generalize it to humans as we have different physiology to animals. Also both studies do not take in to account the evolutionary approach to aggression.
Dopamine also plays a role in aggression, although it is not as well established as the link between serotonin and aggression. Buitelaar 2003 claims that antipsychotics which reduce dopamine activity in the brain have been shown to reduce aggressive bahaviour in violent delinquents. However this is limited as a study shown by Coupiss and Kennedy 2008 who carried out research in mice and found that a reward pathway in the brain becomes engaged in response to aggressive behaviours and events, and that dopamine is involved as