biological explanations to aggression
limbic system
• Papez + Maclean linked limbic system to emotional behaviours
• limbic system = hypothalumus, amygdala + parts of hippocampus
• reactivity of amygdala predictor of aggressive behaviour + plays key role in how mammals asses + respond to envoiromental threats
Gospic et al
• amygdala activity illustrated by Gospic et al
• participants subjected to mild provocation
• when participants acted aggressively fMRI scans showes fast + heightened response by amygdala
• benzodiazepine (reduces arousal) taken before provocation led to two effects: decreased activity or halved number of rejection
hypothalumus, amygdala + prefrontal cortex
• hypothalumus: responsible for regulation of autonomic nervous system, which in turn regulates responses to emotional circumstances
• amygdala: responsible for attaching emotional significance to sensory infomation
• prefrontal cortex: feelings are monitored + interpreted which then triggers physical response, crucial for regulating social behaviour + aggressive responses
serotonin
• thought to reduce aggression bu inhibiting responses to emotional stimuli that might otherwise lead to aggressive response
• low levels of serotonin within brain been linked to increase to impulsive behaviour, aggression + violent suicide
testosterone
• male sex hormone
• higher levels of testosterone associated with increased aggressive behaviour
• Lindeman et al found that young males who behaved aggressively when drunk had higher levels of testosterone than those who don't
Kulver + Bulcy
• using rhesus monkeys removed main areas of limbic system (amygdala, hippocampus, etc)
• monkeys absence of emotional, motor + vocal reactions around fear + anger
• lost understanding of group heiraches
• demonstrates importance of limbic system in regulating aggressive responses
• hard to extrapolate monkey to humans
• similar neural structures but different ways of showing aggression with monkeys only showing physical aggression but humans showing verbal + physical aggression
Wong et al
• MRI scans 19 violent male criminals from broadmoor hospital + compared size of amygdala with control group of 20 non-violent people
• volume of amygdala significantly smaller in violent criminals
• supports role of amygdala + limbic system in aggression
• lack of population validity + gender bias
• beta bias (research used to explain behaviours in males + females yet only undertaken on males)
Nature vs Nuture
• biological approach sits of nature side
• explains aggression through neurotransmitters + hormones
• however, we know aggression can be learnt
• Bandura social learning theory 'Bobo dolls' (nuture)
Ferrari et al
• provides support for role of serotonin
• allowed adult male rats to fight with another rat at specific time for 10 days
• 11th day rat not allowed to fight
• dopamine levels raised 65%, serotonin levels reduced 35%
• despite rat not fighting, brain chemistry altered
• cause + effect issue
• did low levels of serotonin cause aggression or are low levels of serotonin a response to aggression being carried out?