Brain structure + functioning - Explanation of aggression Flashcards
How was Phineas Gage before + after the accident?
Before = Responsible, intelligent, liked by others, religious
After = Still intellectually capable, but personality + emotions changed -became impulsive, language offended many, lost his job
What happened during Phineas Gage’s accident?
Gunpowder exploded whilst laying railway tracks, launching 3cm thick 90cm long iron bar through face, skull, brain
Damaged frontal cortex of brain
What conclusions were made about Phineas Gage + brain structure linked with aggression?
Damage to prefrontal + medial lobes may encourage impulsive behaviour + aggression
What are the different types of aggression?
- Sexual aggression
- Fear-induced aggression
- Irritable aggression
What are the specific types of aggression shown in animals through animal research? What parts of brain cause it?
- Offensive behaviour (physical attacks) = Medial hypothalamus
- Defensive behaviour (response to attack) = Dorsal hypothalamus
- Predatory aggression (attacks for food) = Lateral hypothalamus
What is the role of the amygdala + the prefrontal cortex?
Amygdala = Centre for emotions, emotional behaviour, motivation
Prefrontal cortex = Social interaction + regulation of behaviour
What is the roles of the hypothalamus + hippocampus?
Hypothalamus = Maintains homeostasis through regulation of hormones
Hippocampus = Takes STMs + converts them into LTMs. Associated with aggression due to roles in emotional regulation + fear learning
What research has shown that the amygdala is linked to aggression?
Kluver + Bucy (1939) = Found that lesions to medial temporal lobes may in monkeys got rid of aggressive behaviour
What research links the prefrontal cortex to aggression?
Damasio (1985) = Murderers had lower glucose metabolism - offenders who showed impulsive aggression couldn’t regulate behaviour due to low level of functioning
What research links the hypothalamus to aggression?
Hess (1928) = Demonstrated ability to induce aggressive behaviour in cats by electrical stimulation of hypothalamus
Whats the research that links the hippocampus to aggression?
Chang + Gean (2019) = Found stress in socially isolated mice activates ventral hippocampus neurons, inducing aggression
How has serotonin been used to explain aggression?
Low levels of serotonin lead to increase in aggression levels, since its role is to inhibit aggressive social responses
How does serotonin normally reduce aggression levels?
Prevents stimulation of amygdala, which increases aggressive behaviour because it acts on impulses
How has dopamine been used to explain aggression?
Increased dopamine levels produce increased levels of aggressive behaviour
Amphetamines also increase dopamine levels
