Aggression Flashcards
Neural mechanisms
Limbic system:
Triggers an aggressive response to threats.
Amygdala attaches emotion to sensory information.
Activity in the amygdala can predict aggressive behaviour.
Hypothalamus regulates the autonomic nervous system, which also regulates responses to emotional situations so if damaged it can cause aggressive responses.
Serotonin:
The PET-1 gene is linked to the production of serotonin which decreases aggression. Damage to the gene in mice raised aggression(deneris, 2003)
Serotonin deficiency hypothesis states that decreased serotonin disturbs the orbitofrontal cortex and, therefore reduces the inhibitory effects(of normal serotonin levels) with the consequence that individuals are less able to control impulsive and aggressive behaviour. (Decreased self control)
Neural mechanisms AO3
Limbic system:
Research in Greece found that removing the amygdala reduced aggressive incidents by between 33 percent and 100 percent although small sample of 13.
Phineas Gage study provides evidence that brain damage may have an effect on personality, including aggression.
Serotonin:
Rats selected for reduced aggression levels had higher serotonin and greater levels of serotonin related activity than wild, more aggressive counterparts.
Most evidence is correlational and doesn’t indicate causality.
Research support for the role of serotonin: berman et al. Found that participants given a serotonin enhancing drug gave fewer and less intense electrical to a confederate than people in a placebo group, this gives evidence of a link between serotonin function and aggression that goes beyond correlational findings.
Gender bias: Mann et al. 1990 found aggression rose for men but not for women when they were given a drug that depletes serotonin. Demonstrates beta bias in understanding our responses to aggression.
Hormonal mechanisms
Testosterone is a male sex hormone known for regulating social behaviour such as aggression.
It does this by interacting with the subcortical brain structures, such as the limbic system.
Positive correlations have been found between testosterone levels, and aggressive behaviour.
Dabbs, 1996 found aggressive boys, violent criminals and military offenders all had high levels of testosterone.
Hormonal mechanisms AO3
Higley et al. 1996: individuals with elevated testosterone levels exhibit signs of aggression but rarely commit aggressive acts, suggesting that social and cognitive factors play a mediating role.
For example:
Dabbs and Morris 1990 “blocked pathways to success” study found that when a rich boy with high testosterone returned home from the army, he was less likely to get into trouble, but when a poor boy with high testosterone came home from the army he was more likely to get into trouble.
This suggests testosterone doesn’t simply cause aggression, but it makes testosterone more likely as a response to frustration which would’ve felt as necessary response for the poor boys due to their frustrating circumstances.
Neural and hormonal mechanisms general criticisms AO3
Much of the evidence is only correlational and may not prove causation. It isn’t clear wether the hormones promote aggression or aggressive behaviour stimulates hormone production.
Reductionist: sees only biological factors, overlooking social issues such as de-individuation
Deterministic: assumes humans have no choice and will follow primitive behaviour patterns.
Overlooks effects of socialisation and other environmental issues such as environmental stressors.
Much of the work on neurotransmitters has been done on animals and may not apply to humans so easily.
Genetic factors
MAOA gene:
Also known as the warrior gene. It produces monoamine oxidase which metabolises neurotransmitters, including serotonin, dopamine and noradrenaline. If this gene is dysfunctional it can cause low MAOA activity which means these neurotransmitters are not regulated properly leading to aggressive behaviour.
Brunner et al found that male family members who had histories of impulsive, aggressive behaviour had low levels of MAOA and low activity version of MAOA gene.
Twin studies:
Coccaro found aggressive behaviour to have a 50 percent concordance rate in MZ twins and 19 percent for DZ twins. For verbal aggression this was 28 percent for MZ and 7 percent for DZ.
XYY genotype:
Suggested that those with the rarer XYY genotype are more inclined to aggressive behaviour.
AO3 for the twin studies, XYY and MAOA
Animal research MAOA:
Godar et al. Selectively bred mice without the MAOA gene. They showed increased aggression as well as increased levels of serotonin. If they were given fluoxetine to reduce serotonin they became non aggressive again.
Contradicting research XYY:
Theilgaard found that XYY genotypes may cause an increase in height but not aggression in men.
Self report twin studies:
Rhee and waldermans meta analysis of twin/adoption studies showed that genetic influences on aggression were greater when using self report rather than teacher/parent reports. This suggests the way aggression is measured can affect conclusions about the link between it and genes.
General criticism for genetic factors AO3
Deterministic:
Assumes humans have no choice and will follow quite primitive behaviour patterns.
Reductionist:
Danger of seeing only biological factors and overlooking social psychology such as individuation. Overlooks effects of socialisation and other environmental issues such as environmental stressors. Genetic factors do not work in isolation but interact with environmental factors aswell.
Ethological explanation
Ethology is where we learn about human psychology from studying other animals.
.Conrad Lorenz believed that aggression was an innate adaptive response, something which had evolved in humans and animals to help them survive by:
-see off predators: e.g group of hissing geese can drive off a fox. If geese survive the gene leading to aggressive response will be passed on.
-getting resources: Lorenz also suggested that aggression was aimed at same species a lot to compete for territory or sexual partners, but some animals could damage eachother in the process e.g wolves, lions.
This would be maladaptive(bad for the species) so they fight until one backs down, not to the death, just to establish who is stronger and who is weaker. Lorenz observed that most intra species aggression consisted mainly of ritualistic signalling(displaying teeth) and rarely became physical.
This creates a society in which each individual knows their place. They have evolved ways of warning each other to back off(bark, cats hiss)-tinberg called these FAP(fixed action patterns)
innate releasing mechanism(IRM) and fixed action patterns(FAP)
Aggression can be a result of an innate releasing mechanism(IRM) which triggers a fixed action pattern.
Creatures have evolved an instinctive response to certain things, e.g. a red rag to a bull.
-an IRM is a biological structure/process that is activated by an external stimulus. When it is activated it triggers a FAP which is a behavioural sequence that is universal to the species.
Lea(1984) analysed FAP, 5 features:
- Stereotype: behaviour follows a certain pattern each time.
- Universal: all the animals in that species use the same type of threat
- Innate: all the animals in the species seem to be born with it and don’t have to learn it.
- Ballistic: once it starts, it cannot simply be stopped
- Specific triggers seem to set it off(IRM)
IRM and FAP AO3
IRM:
cannot be generalised to humans, humans can act upon free will, unlike animals, human aggression is extremely destructive, but we seem to have an element of control(our processing might not be auto/innate)
Aggression cannot be truly measured in animals behave the intent is not known and cannot be communicated(may be an act of survival not aggression)
FAP:
Tinberg presented male sticklebacks with a series of wooden models of different shapes. The red on the competing males underbelly is the stimulus that triggers the IRM that, in turn, leads to the aggressive FAP.
He found that if the model had a red underside, the stickleback would aggressively attack it. No red meant no aggression. Once triggered, FAP ran its course to completion without any further stimulus.
Breland and breland found that animals tend to revert to instinctive behaviour regardless of training. This would support the FAP theory.
Ethnological explanation AO3
Not ritualistic:
Goodall observed chimps systematically killing another group despite risks to their own survival and therefore not seeming to be adaptive.
Cultural differences:
Nisbett 1993 found that South American white males would respond more aggressively than North American white males when insulted. Suggest aggression is a learnt social norm and not innate.
Modal action patterns:
Evidence suggest that behaviours are not fixed and can be influenced by the environment. There may be an instinctual drive but it can vary due to training or different types of encounter.
Evolutionary explanation
States that aggression is adaptive but has other adaptive functions other than gaining resources or status. Men could be more aggressive than women because they could be trying to keep their mate.
Believes men are at the risk of cuckoldry(uncertainty of the offspring being theirs) and so use adaptive mate retention strategies to stop their mates from being unfaithful.
Mate retention strategies
Includes:
Direct guarding: males being vigilant by checking where their has been or looking at their phones etc.
Negative inducements: using threats to prevent infidelity.
Bullying
Characteristics associated with bullying make a mate more attractive as it demonstrates strength and reproductive success to females. Women can also use bullying behaviour to secure their partners fidelity and prevent them from being unfaithful.
