BIOLOGICAL - EXPLANATIONS OF AGGRESSION Flashcards
NTs as an explanation of aggression
->aggression is antisocial behaviour, generally with intent to harm, (eg. physical, verbal, psychological/emotional aggression)
SEROTONIN:
how might it explain aggression?
->serotonin is a NT associated with aggressive behaviour
->normal levels of serotonin exerts a calming, inhibitory effect on neurons in the brain (amygdala)
->low levels of serotonin remove this inhibitory effect with the consequence that individuals are less able to control their impulsive and aggressive behaviour
->researchers have found that lower serotonin levels lead to higher levels of aggression
have we got any evidence to support the role of serotonin influencing aggressive behaviour?
->Mann Et Al (1990)
–>administered drug dexfenfluramine to ppts to deplete their serotonin levels
–>ppts were given questionnaires to assess hostility and aggression levels
–>they found increased levels of aggression in males who had taken the drug, suggesting low levels of serotonin lead to higher aggression levels
->Raleigh Et Al (1991)
–>they fed vervet monkeys experimental diets
–>group 1: diet was high in tryptophan, which increased serotonin and decreased aggression
–>group 2: diet was low in tryptophan, which decreased serotonin and increased aggression
DOPAMINE
how might it explain aggression?
->the NT dopamine can affect the feelings of reward and pleasure
->however, increased levels of dopamine have shown an increase in aggressive behaviour
->when dopamine increases, serotonin decreases, reducing the prevention of stimulation of the amygdala
evidence to support the role of dopamine in influencing aggressive behaviour:
->Lavine
–>found that increased dopamine levels through the use of amphetamines was associated with an increase in aggressive behaviour
–>therefore suggesting that high levels of dopamine correlate with higher levels of aggression
hormones as an explanation of aggression
->aggression is antisocial behaviour, generally with intent to harm, (eg. physical, verbal, psychological/emotional aggression)
TESTOSTERONE
->testosterone is one of the androgen hormones (male hormones) which means it produces assertive characteristics
->males produce testosterone in the testes and levels of testosterone peak in young males and gradually declines with age
->the link between testosterone and aggression is well established on research on mice and other non-human animals
->90% of the criminal population are males
->people castrate their male dogs to make them less aggressive
CORTISOL
->cortisol is produced by the adrenaline cortex and is a stress hormone
->it has a number of functions including releasing stored glucose from the liver and controlling swelling after injury, and it supresses the immune system
->a hypothesis is that cortisol (and feelings of stress) mediate the acts that people carry out, but that some people produce less cortisol and feel less stressed when committing acts of violence against others
STRENGTHS:
->supporting research: Kolat (1998)
–>reported that in 15-25y/o men, those with the highest levels of circulating testosterone also showed the highest levels of aggressive behaviour as measured by crime statistics
–>in non-humans, castrated males fight the least, therefore supporting that testosterone causes aggression
->there are shared genes between humans and animals
–>the hypothalamus and limbic system in humans and rodents allow for generalisations to be made, eg. the hypothalamus and aggression in animals links to that area in the limbic system in humans too
–>therefore, results from animal studies can be generalised to humans
->application:
–>anti-androgen medication decreases testosterone, eg. MPA is given to sex offenders in rehabilitation
–>this decreases their likelihood of reoffending
WEAKNESSES:
->research into the relationship between testosterone and aggression is practically difficult
–>this is because the only reliable measurement of brain testosterone is by a lumbar puncture injection to the spine
–>therefore, studies often use less reliable measurements instead (eg. blood and saliva samples)
->in humans the data tends to be correlational data, meaning that C&E cannot be drawn
–>there are links between cortisol and aggression, but there could be other variables involved in the cause of their aggressive behaviour
–> therefore, valid conclusions cannot be drawn
evolution and natural selection as an explanation of aggression
->aggression is antisocial behaviour, generally with intent to harm, (eg. physical, verbal, psychological/emotional aggression)
->evolutionary explanations of aggression suggest that aggression serves an important function in terms of both individual survival as well as reproductive potential
->aggression is an innate response passed on through generations to ensure reproductive success
->competition arises when resources are limited and animals must compete in order to survive and reproduce
->aggression has evolved to increase status against competition, to make the aggressor more attractive to the mate, in order to keep hold of them to pass on their genes to their offspring
->aggression is used to protect the young to give them the best chance of survival
->it is suggested that our ancestors passed on their aggressive traits to their offspring through their genes, and had to be aggressive to ensure reproductive success
AGGRESSION IN MALES:
->males want to FIND and KEEP a mate (to reproduce and pass on genes)
–>this creates competition for a mate
–>males fight other males to gain a female mate
–>this gives the male higher status as he’s seen as stronger, which gives him more access to resources for his own survival as well as his mate and offspring (so not engaging in conflict w/ other males can therefore be costly)
->once the male has a female mate, he will show guarding behaviour so the female doesn’t get poached by other males
AGGRESSION IN FEMALES:
->females are generally viewed as less aggressive than males as a woman has nothing to gain by exhibiting aggression (as their aim is to secure a valuable mate)
–>therefore, females have evolved low-risk and indirect strategies in conflict (eg. using gossip to decrease the attractiveness of competing females)
->females may fight other females to ensure they stay away from her male
–>a female may be jealous if her male is investing his limited resources into someone other than his mate and offspring
STRENGTHS:
->research to support: Daly & Wilson (1985)
–>a review of murders found that the motive behind most conflicts was status. The victims and offenders were likely men of low status and without a mate (unemployed and unmarried)
–>most victims/offenders knew each other, so understood the status of their rival (if men of the same status fight, whoever wins gains higher status)
->research to support: Buss (1987)
–>used a sample of 37 different cultures; found that males consistently values female chastity highly, whereas women valued loyalty and honesty more
–>this may be because emotional infidelity is more likely to result in the female and her child being left with no resources
WEAKNESSES:
->research against: Harris (2002)
–>studied infidelity and found no gender differences: men and women both focused on emotional infidelity as more unacceptable, which challenges the evolutionary approach (as according to this theory, males should be more concerned about physical infidelity)
->evolutionary theory is reductionist
–>this is a weakness as it suggests that our behaviour (such as mate selection) is a result of dispositional factors or the role of the environment
–>it is likely that we are attracted to individuals that we are exposed to or have increased contact with
brain function/structure to explain aggression
->aggression is antisocial behaviour, generally with intent to harm, (eg. physical, verbal, psychological/emotional aggression)
PREFRONTAL CORTEX:
->role: personality, decision making, self restraint
->link to aggression: controls impulsive behaviour, acts as a voice of reason, doesn’t mature until early-mid 20s
(S)->RTS: Phineas Gage: metal rod through PFC, before accident he was mild mannered and gentle, post accident he was rude: “no longer Gage”
(W)->case studies not generalisable
AMYGDALA:
->role: perception of emotion, links emotion to memories, fear conditioning
->link to aggression: responsible for quickly evaluating the emotional importance of sensory info
(S)-> RTS: Egger: cats amygdalas were electrically stimulated and they began to react aggressively (eg. hissing), whereas when stimulation was removed they were no longer aggressive
(W)->animal studies not ethical
HYPOTHALAMUS:
->role: link between NTs and hormones
->link to aggression: controls aggressive behaviour and responses to emotional situations
(S)->RTS: Hess (1928) electrically stimulated particular hypothalamic sites in cats, which rapidly increased biting attacks
(W)->animal studies not generalisable
HIPPOCAMPUS:
->role: converts STM to LTM
->link to aggression: learning right v wrong, this causes reoffending as they can’t remember the punishment of a crime
psychodynamic explanation of aggression
AO1:
how does the id cause aggression
->the id is based on the pleasure principle, it is irrational and does not understand logic
->if it is denied of it’s pleasure it becomes frustrated, therefore this can lead to aggressive and violent urges to get the pleasure it demands
how does the superego link to aggression?
->the superego is based on the morality principle and makes us feel guilty about being aggressive
->it starts with the oedipus complex as, around age 5, a boy will gain sexual desire for his mother - this makes the child aggressive towards his father as he is viewed as a rival
->as conflict arises, he will fear his father and internalise his inappropriate feelings
how does the ego deal with the frustrations and conflict from id and superego:
->the ego must strike a balance and to do this it employs defence mechanisms to allow the urges of the id to be channelled in an acceptable way
->eg. a boy who feels aggressive towards his violent father and cannot express his feelings directly may use the defence mechanism of displacement to take out his urges on smaller, weaker children
AO3: EVALUATION
E->(strength) Megargee (1966) documented a series of cases of violence carried out by people who were regarded as passive and harmless
–>eg. an 11 y/o boy stabbed his younger brother 34 times, but was always described to be gentle-natures and softly-spoken
–>such cases demonstrate catharsis - a sudden explosion of anger after an intense build up of unreleased aggression
A->(strength) this theory can be applied IRL
–>it suggests that the cause of aggression is unresolved conflicts in the unconscious mind
–>therapy and psychoanalysis can be used to resolve these conflicts, and sports like boxing can be cathartic for pent up aggression
C->(weakness) SLT (alternate theory)
–>suggests that aggressive boys learn behaviour through observation of aggressive role models
–>Bandura’s research is more credible than Freud’s as it is falsifiable and has better application (eg. the watershed)
H->(weakness) Freud believed that women have a weaker superego than men, which would cause there to be more female than male criminals
–>Hoffman (1977) indicates that females show stringer moral orientation than males at all ages, which means they are less likely to commit crimes
–>90% of the criminal population is male, so Freud’s theory cannot be true
Freud’s psychodynamic theory
DEFENCE MECHANISMS:
->repression: pushing bad experiences or negative emotions to the back of your mind so you forget about it
->denial: making yourself believe something won’t happen when in fact it will
->displacement: this is where you transfer your feelings onto something/someone else
->rationalisation: explaining our actions so they make sense and we won’t feel bad about them
->sublimation: people are able to transform unwanted impulses into something that is less harmful and often even helpful (eg. cleaning when angry)
->projection: when unacceptable thoughts are dealt with by saying they are someone else’s thoughts so the ego can deal with the feelings
->regression: reverting back to a child-like state because you can’t get what you want, and it is also a way of dealing with stress and avoiding conflict
THE STRUCTURE OF THE PERSONALITY:
->Freud argues that the personality is made up of 3 parts: id, ego, superego
ID:
->the id is innate, it is self-seeking and based on pleasure
->it is the instinctive part of the personality and comprises of biological urges (eg. food, warmth, shelter)
->dominant id=violence and aggression (causes criminals)
EGO:
->the ego develops at 2-3 years old and acts as an executive, trying to satisfy both the id and superego
->it operates on reality principle therefore it is irrational, logical, and mostly conscious part of your personality
->the ego makes us use defence mechanisms in order to reduce anxiety
SUPEREGO:
->id and ego
->develops at 4-6 years old
->operates on the morality principle and idolises good actions: the superego will make us feel guilt
->this causes the child to internalise morals/social norms
->deviant superego (has deviant morals and values) = justifies crime
->weak superego = weak morals
->strong superego = very string morals (leads to lots of anxiety build up until explosion - called catharsis)
