3.1.3 the brain and aggression Flashcards
How is the brain separated?
-2 halves called hemispheres
-both sides share many of the same features (bilateral)
What is the process of looking at the hemispheres separately?
lateralisation
How are the hemispheres joined?
joined by corpus collosum which passes info between the 2 halves
How do the different genders use the hemispheres?
Women use both halves more, men are more right brain dominant
What are lobes?
regions of the brain which give generalised areas for behaviour
How many lobes?
6
What are the 6 lobes called?
frontal lobe, parietal lobe, occipital lobe, temporal lobe, cerebellum, brain stem
What is the role of the frontal lobe?
controls behaviour and emotions
What is the role of the parietal lobe?
perception, spelling and numbers
What is the role of the occipital lobe?
vision, colour and identification
What is the role of the temporal lobe?
language, facial recognition, hearing and speech
What kind of behaviours is the limbic system involved in?
emotional and motivational behaviours
What is the limbic system made up of?
hypothalamus, pituitary gland, amygdala, hippocampus
What does the hypothalamus do?
-acts as body’s smart control coordinating centre
-carries out homeostasis
-influences emotional and motivational behaviour
-link between NTs and hormones
Link between hypothalamus and aggression
-warped amount of hormones released (eg too much testosterone or not enough serotonin/dopamine
Evidence for hypothalamus and aggression
-Alpers studied a well mannered lawyer who suffered a tumour in the medial hypothalamus and began to display aggressive outbursts
What does the pituitary gland do?
-acts as body’s master gland and controls other glands
-releases hormones
What does the amygdala do?
-important in survival as it processes fearful and threatening stimuli
-range of behaviours such as sex and aggression
-emotional centre
-links emotions to memories. perceives emotions
How does the amygdala link to aggression?
-when damaged, emotions can’t be processed properly which can lead to intense responses
-left side controls fight/flight
-right side controls emotional memory
-could malfunction and cause drastic emotions eg, due to tumor
Evidence for the amygdala and aggression
-Raine discovered murderers had lower glucose metabolism in left amygdala and greater in right
-animal experiments showed lesions to amygdala could abolish aggression eg Downer cut part of amygdala in monkeys and visual signals caused no response as ther was no amygdala to reach
What does the hippocampus do?
-vital role in learning and memory
-involved in forming LTMs and making them resistant to forgetting
Link between hippocampus and aggression
-damage means can’t form LTMs and remember consequences of behaviour which causes recidivism
Evidence for hippocampus and aggression
-Chang and Gean found that stress in socially isolated mice activates their hippocampus neurons which induces aggression]#
What does the prefontal cortex do?
-role in personality
-role in decision making and self restraint
-control over social inhibitions
-problem solving and planning
Where is the prefontal cortex?
in frontal lobe
How does the prefontal cortex link to aggression?
-controls personality so can make people violent/unlikeable
-when damaged, emotions can’t be processed and behaviour becomes intense
-when underactive, impulses can’t be inhibited
Evidence for prefontal cortex and aggression
-Phineas Gage had damaged prefontal cortex and underwent major personality change
-Raine found murderers had lower glucose levels in PFC, making them impulsive and lacking self control
How might serotonin explain aggression?
-neurotransmitter that inhibits aggressive social response by preventing stimulation of amygdala
-low levels means there’s less inhibition of amygdala stimulation, so it is easily activated by external events and causes impulsivity
Evidence to support serotonin influencing aggressive behaviour
Mann et al gave ppts drug ‘dexfenfluramine’ to lower serotonin levels, ppts given questionnaire to measure aggression levels which were increased
-only gave drug to men which introduces gender bias
How might dopamine explain aggression?
appears to be a link between dopamine and increased levels of aggressive behaviour
Evidence to support dopamine influencing aggressive behaviour
-Lavine used amphetamines to increase dopamine levels and found an increase in aggression
-antipsychotic drugs used to reduce dopamine and therefore aggression
-HOWEVER this is reductionist and is insufficient to explain complex behaviour
