Neural and hormonal influences Flashcards
what are the two neural explanations of aggression
1) limbic system
2) serotonin
what is the limbic system
a system of structures lying beneath the cortex made up of the amygdala, hippocampus and hypothalamus associated with emotional behaviour
what is the role of the amygdala
responsible for quick evaluation of emotional importance of sensor information and prompting an appropriate response
outline research which suggests the amygdala may be involved in agression
research found if certain areas of the amygdala are stimulated electrically an animal responds with aggression such as snarling or aggressive postures , if these areas are removed then the animal no longer responds to stimuli which would normally lead to rage
Kluver and Bucy found the destruction of the amygdala in a monkey dominant in their group would lead to it losing its dominant place in the social group
what is the role of the hypothalamus in aggression
involved in the formation of long term memories therefore allows animals to compare conditions of a current threat with similar past experiences allowing an appropriate responce
an impaired hypothalamus prevents the nervous system from putting things into relevant and meaningful context so may cause the amygdala to respond inappropriate to a stimuli resulting in aggression
outline the role of serotonin in aggression
normal levels of serotonin cause a calming, inhibitory effect on the brain inhibiting the firing of the amygdala
low levels of serotonin reverse this effect so individuals are less able to control impulsive behaviour such as aggression= the serotonin deficiency hypothesis
therefore when the amygdala is stimulated by external events it becomes more active causing individuals to act on impulses increasing aggression
outline the role of testosterone in aggression as a hormonal explanation
it is thought the hormone testosterone influences levels of aggression and is associated with the development of male characteristics but also implicated with aggressive and dominance behaviours
outline research which supports the role of testosterone in aggression
1) Dabbs et al- measured salivary testosterone in violent and non-violent criminals, those with highest testosterone levels had history of primarily violent crimes compared to non-violent criminals which had lower levels
evaluate the neural explanation of aggression
1) supporting research= role of the amygdala by pardini et al= longitudinal study of male pps from child to adulthood with some pps having varying histories of violence underwent an MRI at age 26- pps with lower amygdala volumes showed higher aggression and violence
2) issue and debate= nature vs nurture- ignores nurture explanations such as childhood experiences ie bobo doll study showed effect of modelling
3) research method = longitudinal studies, use of animal studies, use of lab studies
4) practical application = free will and criminal responsibility- if nature the view that it 8is biologically predetermined suggest violent crimes may not be their fault- it allows justification for violent acts as it is ‘in their biology’ eg Whitman who murdered his wife and mother and then shot 45 individuals was found to have a tumour on his amygdala
evaluate the hormonal explanations of aggression
1) critical research= inconsistent evidence- despite many studies showing a positive relationship between testosterone and aggression other studies show no such relationship eg +ive reported between levels of testosterone and self reported levels of aggression in inmates but on the other hand no correlation between testosterone and actual violent behaviour in inmates
2) issue or debate= nature vs nurture/ free will and determinism
3) research method - correlational research
4) excuse of crimes eg Whitman who killed his wife nd mother and shot 45 individuals- post mortem found a tumour on amygdala
