raine et al Flashcards
(15 cards)
what is the hypothesis of raines study
seriously violent individuals would have relatively localised brain dysfunction in the pre frontal cortex, thalamus, amygdala, corpus callosum, hippocampus, and the medio temporal lobe
what is the aim of raines study
to show that the brains of murderers who pleaded guilty by reason of insanity(NGRI) are different to the brains of non murderers
what was the sample of raines study
41 NGRI murderers matched by sex, age and other similarities(39 men and 2 women) who had all been referred to the University of California Irvine Imaging centre
41 non murderers some with a history of brain damage or schizophrenia(6 schizophrenic people were test screened to see if they had any previous psychiatric illnesses and they didn’t)
what were the experimental controls for the sample in raines study
all offenders were in custody and kept medication free for 2 weeks before, during, and 2 weeks after the experiment
14 non white murderers
tests to see that being left or right handed didn’t have an affect on behaviour
what were the materials in raines study
thermoplastic head holder moulded to the patients head
PET scanner
FDG
CPT(continuous performance task)
what was the procedure in raines study
10 mins before FDG injection, patients were given practice trials on CPT
30 seconds before injection, the real task started so initial task novelty wasn’t labelled/recorded
once injected they were monitored for 32 mins and were scanned in PET scanners
brains were scanned 10 times at 10 mm intervals to pick up differences in glucose metabolism in cerebral cortex and subcortical layers
brain regions identified using cortical peel technique and box technique
what were the results in raines study
no significant difference in the task performance between the 2 groups but there was a significant difference in brain metabolism of glucose in a number of areas
frontal lobes has reduced glucose metabolism relative to controls
parietal lobes and corpus callosum had a lower glucose level than controls
limbic system abnormalities(reduced in the left, more so in the right)
what was the conclusion in raines study
NGRI murderers brains were different to non murderers
damage to PFC can result in impulsivity, lack of self control, immaturity, emotional changes and the inability to modify behaviour
abnormalities in the amygdala could be relevant to fearlessness theory of violence
reductions in glucose metabolism in parietal lobes have bee correlated with reduced verbal ability and deficits in arithmetic and reading
uncertain that violent behaviours are caused by brain abnormalities alone
evaluate a weakness of the generalisability of raines study
low in generalisability
sample only included people who plead NGRI for murder
this is a very specific subgroup of offenders and does not represent all violent people or all murderers so findings may not be applicable to the wider population
evaluate a strength of the generalisability in raines study
had the largest sample ever to have used PET scans in the study at the time with 41 pps in each group
a relatively large and well matches sample increases confidence in the representativeness of the findings within the context of NGRI offenders making the data more robust compared to other studies
evaluate the reliability in raines study
high in reliability
standardised procedures were used such as the same continuous performance task and PET scan protocol for all pps
the same methodology was applied consistently, so the study can be repeated by other researchers to test for consistent results with NGRI offenders
increasing its reliability and scientific credibility
evaluate the applications of raines study
can be applied to real life
understanding brain abnormalities in violent offenders can from criminal justice policies, risk assessments and early intervention strategies
if particular brain patterns (eg. reduced activity in PFC) are linked to violence, professionals could use this info to identify people at risk and maybe intervene before criminal acts occur
ethical considerations must be taken into account when applying to real life
evaluate 2 weakness of the validity of raines study
findings only describe brain differences but doesnt explain them
brain scans were carried out after the violent acts were committed so we cant say for sure that the brain differences were present before murders
raine couldnt establish a cause and effect between brain dysfunction and violent behaviour
question the notion that all murderers are violent, NGRI criminals arent always charged with murder due to a violent act
this challenges the assumption that brain abnormalities are associated specifically with violence
some pps may have committed murder in events involving psychosis or impaired judgement, not violence
evaluate the task validity of raines study
low in task validity
the pre scan task(CPT) had no bearing on violent behaviour
task may not have activated the brain regions relevant to aggression or violence
if pps were engaged in a task with emotional or aggressive content, maybe the difference in brain activity would be more pronounced
evaluate 2 weaknesses of the ethics of raines study
informed consent was given by murderers pleading NGRI so they may not have had the capacity to consent
pps with significant mental health issues may not have fully understood the implications of participating in a brain scan study
this raised concerns about if ethical guidelines were properly upheld
the medication free 2 weeks may have raised ethical issues
pps were taken off their psychotropic medication before the scan which could have caused physical or psychological harm
this raises concerns about whether their well being was protected
