Aggression Flashcards
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.
