The Brain + Theory To Plain Aggression Flashcards
Aim of Raine’s study
- to investigate whether there were brain differences between violent murderer who had pleaded not guilty by reasons of insanity compared to a matched control group of non murderers using PET scans.
- specifically on seeing any dysfunction in pre frontal cortex which was thought to involve in violent behaviours
Procedure of Raine’s study
- 41 murderers (39 men, 2 women) who had pleaded not guilty by reasons of insanity, charged with manslaughter, 6 are schizophrenic
- matched pair with control groups based on age, gender and mental capacity
- did a practice task then inject radioactive glucose tracer then did 32 minutes continuous performance visual task that suppose to increase brain activity
- PET scan after the task
AO1 Findings of Raine’s study
- murderers had less activity in PFC for self control compared to control group
- less activity in left amygdala and more activity in right amygdala for fear
- more activity in right thalamus for hormones
AO1 conclusion of Raine’s study
- violent behaviours are controlled by areas of brain
- areas with abnormal activity are associated with lacks of fear, lowered self control, increased aggression and impulsive behaviour and problems with controlling and expressing emotions
- indicates a link of abnormal brain activity and predisposition of violence
Function of frontal lobe
- decision making
- self control
- personality
Function of Parietal lobe
- language
Function of temporal lobe
- sensory and auditory
Function of occipital lobe
- visual and sensory
Structure of mid brain
- contains periaqueductal grey matter, links with amygdala and hypothalamus with prefrontal cortex
Role of mid brain
- coordinating and integrating behavioural response to internal and external stimuli e.g. pain or threat
One study supports explanation of mid brain
- Lonstein and stern
= found wen after rats gave birth, had lesions on PAG showed increase in aggression when they faced potential threat, when unfamiliar male rats went near them
Structure of limbic system
- consists of hippocampus, amygdala, hypothalamus
Function of limbic system
- control temperature and flight or fight response
- link with autonomic systems responds automatically without planned
Role of hypothalamus
- maintain homeostasis via the regulation of hormones
E.g. sexual functioning hormones = testosterone can increase aggression
Role of amygdala
- centre of emotions, emotional behaviour and motivation
- in and external stimuli inputs combined with emotions to give us instinctive feelings or reaction to environment e.g. aggression
- PFC link with amygdala that control expression of aggression
One study that supports explanation of amygdala
- Downer
- study on monkeys with one side of amygdala removed
- if monkeys have visual input connecting to intact amygdala = show aggression
- if their visual input cannot reach amygdala = shows calmer
Role of prefrontal cortex
- control social interaction, regulation of behaviour and regulation of emotions
Role of left and right PFC
L- regulates positive emotions
R- regulates negative emotions
Effect of damaging PFC
- problems with anger management
- irritability and impulse control
What study supports explanation of PFC
- Bachara and va der Linden
= PFC seems to regulate behaviour and defer rewards
= damage can means someone only focus on present but unable to plan for future and pursue immediate rewards and less control on aggressive reactions
Pros of using the brain as explanation for aggression
- supported by case study of Phineas Gage
- supported by Raine et al study
Cons of using brain to explain aggression
- criticism of case study supportiveness
- criticism of support from animal research = anthropomorphic
- reductionists
- biological determination
How is using brain explain aggression reductionist ?
- reduces production of aggression behaviour down to working of specific neural circuits
- ignores other explanation e.g. learning
= insufficient
How is biological determination a drawback of brain explanation of aggression ?
- behaviour is predetermined by bio makeup
- no free will to how you behave, small amygdala and low activity PFC are destined to be aggressive
= people are aggressive have no control, as born that way and are not to blame
What is evolution ?
- all behaviours have an adoptive advantage that promotes survival
- “survival the fittest “ = best adopted to their environment to survive
How can evolution of genes explain aggression ?
- MAOA genes = helps with metabolise of noradrenaline and serotonin and dopamine
= dysfunction of it cause these neurotransmitters can’t be broken down =aggression - high adrenaline = cause hypersensitivity in F/F response = overreact
- excess dopamine = aggression
- low serotonin = reduce control on impulsive behaviour
How can EEA of male explain aggression ?
1) resources = hunting to provide food
2) protection = protect families and offspring = gene pool continues
3) social status = higher social status = more attractive viewed to fight down others
- be more physical aggressive in order to obtain best mate
How does EEA in female explain aggression ?
- Buss suggested women are more verbally aggressive to provide adoptive advantage
= women will verbally degrade others so they look bad = get higher level of men
How does epigenetics explain aggression?
- we are born with predisposition of genes of aggression that needs to be triggered by environment
E.g. MAOA gene
Pros of using evolution to explain aggression
- differences of male and female brain
- supported by Chester
- supported by Mazur
Cons of using evolution to explain aggression
- anthropomorphic of supporting research
- post hoc
- aggression can lead to risk
- alternative theories so reductionist
Describe Chester study on evolution
- found that males have low functioning MAOA gene causes greater period of aggression compared to normal function gene
= t,f , shows dysfunction of MAOA gene leads to inability to regulate aggression and can be passed on the genes of male, supporting evolutionary theory of aggression
How does Mazur supports evolutionary explanation to aggression?
- found difference in inter male fighting in rats in puberty as more aggression = when sexual instinct and ability pass on begins
= supporting theory p, increase validity of theory
How is evolution theory post hoc in explain aggression?
- based on assumptions = we argue that specific behaviour must be adoptive because it persist. Aggression on males persist to promotes gene survival
= questions Validity
Hormones in androgen
- testosterone
- cortisol
- adrenaline
- oxytocin
Features and effect of testosterone
- produced in adrenal gland
- high level = aggression
Features and effect of cortisol
- produced when faced stressor
- low level = aggression
Relationship of testosterone and cortisol
- unbalanced T/CRT ratio = high T+ low CRT = cause aggression
Effect of adrenaline and oxytocin
A- flight or fight response to a stimuli = triggers need of physical fast and strong
O- released by posterior pituitary gland = increase trust between people = low level , aggression
How does prenatal exposure to testosterone impact aggression ?
- prenatal posture has effect on developing brain, leading to increase of spatial and competitive aggression
- stimulates cell growth of amygdala and hypothalamus = sets up the action of testosterone effect aggression
Animal study supporting hormonal explanation of aggression
- young et al = found injecting androgen in pregnant monkeys shown that female babies will have masculine genitalia and act masculine e.g. threatening, aggressive
- Edwards = inject testosterone into female neonatal = made them more aggressive comparing to control groups
Human studies support hormonal explanation
- collaer and Hines
- D’Andrade
- Mazur
Describe Collaer and Hines study
- argued male sex hormones increase likelihood of child likes playing rough and tumble play and physical activity
- exposure to high level male sex hormones at early age effect sexual orientation in puberty
- male sex hormones lead to increase of aggression
Describe D’Andrade study
- found boys average are more aggressive than girls, boys have higher exposure to testosterone both pre and post natal
= suggest testosterone linked to aggression
Cons of hormonal explanation to aggression
-data is correlational
- animal research = anthropomorphic
- ethics of human research
- reductionists
How is data correlational in hormonal theory ?
- cannot establish cause and effect as only studying aggression when someone starts to be aggressive = so unsure if high T cause aggression or aggression cause high T
= t/f, other factors may contribute such as imitation and brain abnormalities = reduce validity
ID of freuds theory
- part of our unconscious mind
- developed from birth
- instinctive part off personality, operates on pleasure principle for instant gratification
- Eros = life + sex drive
- Thanatos= death instinct = attack anything that interferes the gratification of libido
AO1 of ego of freuds theory
- developed at 2 years old
- operates from reality principle, taking account of what is practical
- defence mechanisms used to balance ID and superego to stop the improper impulses to go too extreme
- ideas of norms and social rules are learned so ego do consider when and what is appropriate to do
AO1 of superego of freuds theory
- act on morality principle = determines right or wrong things to do
- develop at 4-5 years old
- controls ourselves to act in a socially acceptable way and consider others
- consist of ego ideal of what we should be and conscience of what we should not be
- controls aggressive impulses
AO1 of how Freud’s theory of personality explains aggression
- ID is dominant, seeking gratification
- Thanatos = repressed emotions to attack anything gets in the way of seeking gratification
- cartharsis = release of aggression
- attack in socially unacceptable way (superego)
- socially acceptable way = sublimation( one of defence mechanism ) e.g. sports and video games (ego)
Pros of Freud’s theory
- supported by Verna and Sullivan study
- supported by megargee and Medelsohn study
What is vernon ad Sullivan study about
- found people after acted aggressively to be made to do frustrated task had reduced heart rate from the high heart rate when acting aggressively comparing to people did not act aggressively.
- supporting freuds that aggression is cathartic as a burst of repressed ID frustration
What is study of megargee about ?
- found people will have big outburst of aggression if they did not let their aggression instinct released in small amount to be build up
- suggest when anger is repressed into unconsciousness, it becomes uncontrollable so needed catharsis
Cons of Freud’s theory
- unscientific = can’t experimentally prove existence of ID, ego and superego
- subjective = use of case studies to develop the theory
- other theories can be argued to explain aggression = reductionist
