Aggression Flashcards
(71 cards)
Analyse Raine et al (1997) - Summary (Aim)
To investigate whether there is a difference in the brain activity of people who have committed murder and those who have not.
Raine wanted to determine if there was a biological reason for some people acting more aggressively than others.
Analyse Raine et al (1997) - Summary (Method)
Used 41 offenders who pled Not Guilty by Reason of Insanity and 41 non-offenders.
Participants were brought to the university of California and were injected with a glucose tracer to allow fora PET scan to find out which parts of the brain were active.
Participants were asked to complete a continuous performance task which was designed to force participants to use parts of the brain that researchers were interested in. such as the Amygdala and prefrontal cortex. They did this task 32 minutes before the PET scan.
The study used a matched participant design as participants were matched on age and gender and the schizophrenics were matched with schizophrenics from the other group.
Analyse Raine et al (1997) - Summary (Results)
It was found that in the NGRI group there was increased activity in the amygdala compared to control group and decreased activity in the prefrontal cortex.
There were no differences in some areas that were associated with mental illness but not violence.
There were abnormal asymmetries as there was reduced activity on the left and increased activity on the right which applies to some areas that have been identified to be linked with violence.
Analyse Raine et al (1997) - Evaluation (Strengths)
The participants participated under protocols and consent forms approved by the Human Subjects Committee of University of California which meant participants were protected from harm and gave informed consent.
Raine ensured there was methodological control by making sure participants were not taking any other medications that may have changed the PET scan results. The participants were also given time to familiarise themselves with the performance task before the study started which improves the reliability of the results.
Analyse Raine et al (1997) - Evaluation (Weaknesses)
The sample of aggressive people only contained murders who pled NGRI which means it doesn’t represent all types of violence so the results cannot be applied to all aggression.
The PET images were unclear and hard to read which reduces the reliability of the results.
It could be potentially be dangerous to apply the findings of the study to wider society. If it is suggested that brain structure leads to violent behaviour, it may lead to defense lawyers using this idea to defend their clients.
Analyse Raine et al (1997) - Link
The prefrontal cortex is responsible for decision-making and impulse control. Its main job is to control our emotional responses to stress. Damage to this part of the brain would reduced the inhibition of the amygdala resulting in higher levels of aggression.
Evidence of this is that neuropsychological tests have found impairment in the prefrontal cortex in juvenile offenders.
The amygdala is a brain structure located in the limbic system that controls our emotional responses. Because of this, the amygdala is strongly linked to feelings of anger or fear that can result in aggressive behaviours.
Analyse Raine et al (1997) - Comparison
Barroni et al did neuropsychological tests that found impairment in the prefrontal cortex in juvenile offenders which agrees with Raine’s findings that murderers who pled NGRI had reduced prefrontal cortex activity.
Summer (2007) found that the aggression levels of a girl who was showing extreme aggressive behaviour went back to normal once she had a tumour removed that was pressing on her amygdala which agrees with the results of Raine which found that murderers who pled NGRI had increased activity in the amygdala.
Gospic et al did FMRIs which found that increased activity in the amygdala was present in participants showing aggressive behaviour which agrees with Raine’s results.
King (1961) demonstrated that when the amygdala was electrically stimulated,
participants became threatening and verbally abusive which also agrees with Raine’s results.
Grafman et al found that vietnam veterans with prefrontal brain injuries demonstrate higher levels of aggression than that which they had shown before the injury which supports Raine’s results.
Bufkin did MRI and PET studies which have shown reduced volume and metabolism of the prefrontal
cortex in aggressive people which agrees with Raine’s findings that murderers who pled NGRI had reduced prefrontal cortex activity compared to the control group.
Analyse Raine et al (1997) - Implications
This could mean that both defense and prosecution lawyers could use brain scans on the accused in order to see whether their brain activity lines up with the brain activity present in violent people. However this could lead to negative consequences as if their brain activity is similar then it may make them seem like a more likely culprit however that isn’t necessarily the case as not as aggressive people are criminals.
Biological Influences - Neural (Limbic system)
The limbic system can affect aggression as it is the part of the brain which controls aggression which controls emotion, learning and memory.
It also regulates our primitive urges such as sleep, appetite, fear and sex drive.
The amygdala is a brain structure located in the limbic system which controls our emotion responses. Because of this it is strongly linked to feelings of anger or fear that can result in aggressive behaviours.
Evidence of this is Summer (2007) which conducted a case study on a 14-year-old girl showing extreme aggressive behaviour as well as epileptic fits. MRI scans revealed a tumour pressing on her amygdala. After it was removed her aggression levels became normal.
Biological Influences - Neural (Prefrontal Cortex)
The prefrontal cortex is responsible for decision-making and impulse control. Its main job is to control our emotional responses to stress. Damage to the prefrontal cortex would reduce the inhibition of the amygdala resulting in higher levels of aggression.
Evidence of this is Barroni et al (2022) which did neuropsychological tests that found impairment in the prefrontal cortex in juvenile offenders.
Biological Influences - Hormones (Serotonin)
Serotonin helps maintain our mood and impulse control. A decrease or lack of serotonin disrupts this mechanism and can lead to an increase in impulsiveness and aggression.
Evidence of this is Virkkunen et al (1994) which found that violent, impulsive offenders have lower levels of serotonin than non-violent offenders.
Biological Influences - Hormonal (Testosterone)
Testosterone is the primary sex hormone in males. It is strongly associated with competition and aggression.
The challenge hypothesis suggests that testosterone promotes aggression when it would be beneficial for reproduction, such as mate guarding or fighting off challengers.
Evidence of this is Edwards (1968) which gave testosterone to female mice and found that they began to act with much more aggression than normal.
Biological Influences - Neural/Hormonal (strengths)
Research studies have found evidence to support the idea that high levels of testosterone can lead to aggression. For example, Van Goozen (1997) conducted a natural observation on people who were transitioning to the opposite sex. It was found that males who were given testosterone suppressants were less aggressive whereas females given testosterone boosters were more aggressive.
Most violent behaviours are carried out by men (who have more testosterone) which supports this idea.
Biological Influences - Neural and Hormonal (weaknesses)
It is unclear whether hormone imbalances cause aggression or aggressive behaviour causes hormone imbalance.
This explanation is reductionist. All aggression cannot be explained purely by biology.
Not all men are violent and if testosterone was the only reason, this would not be the case.
This explanation is deterministic and assumes humans have no free will or control of their aggressive behaviours. We know this is not true and not everyone with hormone/neurotransmitter imbalances will act on their aggressive thoughts.
Biological Influences- Genetic
One specific gene that has been identified to carry the aggression trait is Monoamine Oxidase A (MAOA) which is known as the “warrior gene” due to many research studies identifying a relationship between the gene and increased levels of violence.
MAO is a protein that helps nerve cells transfer serotonin, norepinephrine and dopamine.
MAOA leads to there not being enough MAO which means that there is too much serotonin, norepinephrine and dopamine in the body. This leads to too much adrenaline which causes the hypersensitivity of the fight or flight response.
Evidence of this is McDermott (2009) which found that those with the MAOA gene were much more likely to administer higher levels of hot sauce (causing them more harm and therefore showing more aggression) than those without the MAOA gene.
Biological Influences - Genetic (strengths)
Research evidence into both animals and humans supports the genetic explanation of aggression.
Biological Influences - Genetic (weaknesses)
The high concordance rate for aggression between MZ twins may be due to environmental factors, therefore reducing the validity of the genetic explanation.
The fact that the concordance for aggression in monozygotic twins was not 100% suggests there is another factor that is an influence, and this factor could be linked to the environment.
Another weakness of the genetic explanation of aggression is that it is deterministic. It takes a hard determinist stance that individuals do not choose to be aggressive, instead it is caused by factors beyond their control, i.e. their genetics.
Biological Influences - Evolutionary
Natural selection assumes that animals with the most successful traits for reproduction and survival will pass their genes on to offspring. Aggression can help as it can aid animals in protecting themselves, their families and their resources.
Our limbic systems have evolved to allow us to behave in an aggressive manner should we feel the need to (in order to survive).
Sexual jealousy is a major motivator of aggressive behaviour in males as, unlike females, men can never be completely certain whether or not they have fathered a child. This paternity uncertainty is a result of the very real threat for the male cuckoldry, or having to raise offspring that are not his own.
The evolutionary theory suggests that bullying is an adaptive strategy to increase their chances of survival by promoting their own health and creating opportunities for reproduction. Volk (2012) argued that characteristics associated with physical and verbal bullying behaviours are attractive to the opposite sex.
Evidence of this is Shackleford (2005) which found that men who used guarding or negative inducements were more likely to use physical violence against their partners. These retention behaviours reliably predicted husbands’ use of violence against their wives.
Biological Influences - Evolutionary (strengths)
This theory is supported by research evidence that suggests aggression is an innate behaviour. If this is the case, more research should be conducted so that it can be used to help reduce aggression in society.
Biological Influences - Evolutionary (weaknesses)
This theory could be used to justify violence against women. Assuming men are behaving aggressively as a result of sexual jealousy or competition is a dangerous argument.
This is a reductionist view and does not consider other factors that could influence aggression, for example biological or genetic differences.
This theory is deterministic as it assumes we are controlled by our evolutionary needs - the existence of our prefrontal cortex highlights that we have the ability to make decisions on aggressive behaviour. We are not controlled by our primal needs.
Biological Influences - Ethological
The ethological explanation argues that aggression is an innate behaviour that has an adaptive function.
Aggression is explained as adaptive because it is beneficial to survival and reproductive success.
Aggression can occur because it is an automated response in the brain - animals have an innate neural structure that responds to an external stimuli with an automatic behavioural response.
Therefore if a human or animal is exposed to a threatening stimuli, it will automatically respond in an aggressive manner.
All species have fixed action patterns (FAPs) which are produced by innate releasing mechanisms (IRMS).
For example, when a cat runs, a dog will chase it. The IRMS is the cat running and the FAP is the dog chasing it.
Evidence of this is Tinbergen (1952) which investigated male sticklebacks by presenting them with unrealistic wooden models which either had red patches underneath (similar to red bellies of male sticklebacks) or realistic models without red bellies. All males attacked only the unrealistic wooden models with the red bellies which shows these patches act as a biological trigger to start an aggressive fixed action pattern (FAP) even when there was no threat.
Biological Influences - Ethological (strengths)
Research evidence has shown that our limbic system triggers aggression when in a threatening environment (IRM triggers FAP) which supports the ethological explanation.
Biological Influences - Ethological (Weaknesses)
This explanation is reductionist. The suggestion that genes and instincts control aggression ignores the free will of the individual and the ability of the individual to control their behaviour.
Research has suggested that sequences of behaviours that appear to be fixed and unchanging are greatly influenced by by environmental factors and learning experiences. So FAPs are more flexible than implied by the term “fixed”.
The idea that aggression has evolved into a fairly physically harmless ritual has been challenged by observations of chimpanzees at a national park in Tanzania. Male chimps from one community planned on slaughtering all the members of another group. They prepared this. The violence continued despite the victims showing signs of appeasement and defenseless. These signs did not inhibit the aggressive behaviour of the attacking chimps as predicted by the ethological explanation.
Social Influence - Analysis of Social Learning Theory (Summary)
Social Learning theory is based on the behaviourist model of psychology which argues our behaviours are shaped by our external environments.
Albert Bandura, the man who developed SLT, argued that the model ignored the inner person and that there was a deeper explanation for behaviour.
SLT argues that learned behaviours can be influenced by our social setting and that we learn from each other.
Bandura believed that four things need to happen for imitation of aggression to occur: attention, retention, reproduction and motivation.
Vicarious reinforcement is when a behaviour is more likely to be copied if it is rewarded.