neural + hormonal explanations Flashcards
what is a neural mechanism
related to the nervous system, such as the brain and neurotransmitters
what is a hormonal mechanism
how chemical messengers influence the body
what is the limbic system
a set of neural structures located in the centre of the brain including the amygdala and hypothalamus
what is serotonin
an inhibitory neurotransmitter that is important in controlling and calming aggressive impulsives
what is testosterone
a male sex hormone thought to be responsible for increased aggression
what is the function of the limbic system
process emotional responses
what is the role of the amygdala
identified as being linked to the production of aggressive behaviour
what did MRI scans show about the amygdala
increased activity during aggressive behaviour
what is the role of the hypothalamus in aggression
integrating and expressing emotional responses, it can trigger aggressive behaviour as part of the fight or flight
what is the role of the hippocampus in aggression
the hippocampus stores long term memories, to compare the conditions of a current threat to one previously remembered to prepare a response
what is the role of the orbitofrontal cortex in regulating aggression
the limbic system communicates with this area, the OFC involved in decision making then attempts to control the aggression
what research support is there for the role of the limbic system in aggression?
Egger + Flynn:
found that electrically stimulating the hypothalamus in cats would cause them to show aggressive behaviour towards rats, stimulating the amygdala would either suppress or increase aggressive behaviour
what does the research into the limbic system suggest?
shows that the hypothalamus and amygdala have a role in regulating and causing aggressive behaviour, showing the influence of the limbic system
what is a counterpoint to the research support into the limbic system?
research was carried out on cats, humans are much more complex beings than cats and have many more social factors that may influence aggressive behaviours, so study is limited to what it can tell us about the limbic system and aggression in humans
what did MRI scans reveal about the limbic system?
Paradini:
longitudinal study using male participants, MRI scans revealed those with lower amygdala volume showed higher levels of aggression showing amygdala plays an important role in aggressive behaviours
what was found in monkeys in regards to the limbic system?
Kluver and Bucy:
removed the main areas of the limbic system including the amygdala, hippocampus and surrounding cortical areas.
they found that the monkeys displayed an absence of emotional, motor and vocal reactions normally associated with stimuli or situations eliciting fear and anger.
the destruction of the limbic system in dominant monkeys in social groups also cost them to lose their place
what is a problem with monkey research into the limbic system?
using research using animals to provide evidence for aggression in humans is the differences between animal and human physiology and the question of whether we can extrapolate research findings from animals to human aggressive behaviour.
how does serotonin work in the brain in non aggressive individuals?
has an inhibitory effect, reducing neural activity dampening and quietening aggressive impulses from the limbic system, serotonin is located in the OFC which regulates aggression
what is serotonin like for aggressive individuals?
serotonin deficiency hypothesis suggests that lower levels of serotonin in the OFC result in less control over the limbic systems aggressive impulses
what is tryptophan?
found in foods which is needed by the body to produce serotonin
what research support is there for serotonin affecting aggression?
Passamonti:
when participants had low serotonin levels (after tryptophan depletion), there was reduced communication between the amygdala and the pre frontal cortex.
this suggests that low serotonin impairs the ability of the prefrontal cortex to control aggressive impulses in the amygdala.
individuals with tryptophan depletion also scored higher on an aggression questionnaire
how could you evaluate the research methods used by passamonti?
randomised, double blind procedure to prevent investigator effects and ensure high validity
self report measure susceptible to social desirability
why is there thought to be sex differences in aggression?
males have high levels of testosterone (8x greater)
what is the role of testosterone in aggression, linking it to the limbic system?
high levels of testosterone in the OFC reduces activity, the OFC is then less able to regulate aggressive impulses in the limbic system