Raine research Flashcards
what was the aim of this study?
to study brain activity in murderers and non murderers by using a PET scan to investigate whether there were differences in areas of the brain thought to be involved with violent behaviour
what is a PET scan?
a brain scanning technique in which the participant is injected with a radioactive tracer that is used in energy production by the brain; the molecules of the tracer travels through the blood and their breakdown is detected by a scanner - the brain scans indicate the level of activity in areas of the brain using different colours
what was the sample of this study?
- the experimental group (murderers) was made up of 39 men and 2 women; each had been charged with murder or manslaughter and pleaded not guilty by reasons of insanity but had been convicted
- the control group (non murderers) was matched for sex and age, and for 6 of the participants, a diagnosis of schizophrenia, their mean age did not significantly differ from the experimental group and no participants too any medication prior to the study for two weeks
what is CPT?
is a visual vigilance task; participants watches brief stimuli that appear one after the other, pressing a button each time a specified stimulus appears - this controls for various sensory stimulus in the room, which could cause differences in brain activation that could obscure differences between the groups of participants
what is the procedure for this study?
- the participants were brain scanned during a CPT
- they were allowed to practice the CPT and 30 seconds before being injected with fluorodeoxyglucose tracer, the participants began their full CPT session (this would ensure that the novelty of the task would not appear as an event on the brain scan)
- the CPT scan continued for 32 minutes - after this, PET images of 10 horizontal slices through the brain were taken at 10mm intervals using two techniques to identify regions of the brain; cortical peel and box technique
- the scans were then analysed for activity levels in the different areas of the brain
what is the cortical peel technique?
used for lateral areas - on the side/surface of the brain
what is the box technique?
used for medial areas - inside the brain
what were the findings from this study?
- murderers had less activity in the medial, lateral and parietal prefrontal cortical areas of the brain and also the corpus callosum compared to the control group
- they had abnormally asymmetrical activation in areas of the limbic system (including the amygdala - less activity in the left side of the brain) and less activity on the right side of the brain in the temporal lobe, hippocampus and the thalamus
what is the limbic system?
plays a role in many functions including emotion, processing of social information, motivation, learning and memory
what are the conclusions from this study?
the areas of the brain with abnormal activity increases the risk of criminality
- amygdala, hippocampus and thalamus are associated with aggressiveness
- the amygdala is associated with lack of fear
- prefrontal cortex is associated with impulsiveness
- amygdala, hippocampus and prefrontal cortex is associated with problems controlling and expressing emotions
linked to problems with learning conditioned emotional responses and failure to learn from experiences
lower intelligence which acts as a barrier for individuals and their ability at getting employed is associated with a higher risk of criminality
what is a biological strategy for preventing criminal behaviour?
plastic surgery - if an individual undergoes reconstructive surgery for any facial deformities, it is less likely that they will be labelled as a criminal
what was Lewinson’s study investigating plastic surgery about?
- conducted 450 facial reconstruction surgeries on both men and women and observed consequent behaviour during prison and after their release
- he took four factors into account when selecting his participants; age, number of offences, type of offences and reasons for seeking surgery
- Lewinson found that the effect of reconstructive surgery was to raise morale and reduce hostility; participants were more cooperative with authority figures and were interested in learning a trade (links to self esteem and self concept)
what are the strengths of this study?
- the use of the PET scan is a valid and reliable procedure as it is an objective measure of data
- good level of internal validity as the control group was matched with the experimental group
- good level of predictive validity - the statistical significance of the results and the high number of controls use in this study suggests that the results may be used to predict individuals who may be predisposed to commit murder and then plead not guilty by reason of insanity.
what are the weaknesses of this study?
- the precision of the location of scans is difficult to maintain, so comparisons may be less valid than they appear
- scans still need to be interpreted leading to the potential for lowered reliability
- the sample isn’t of the whole of the prison population as the criminals used were murderers thus ignoring the other wide range of crimes; those committing other crimes may have different patterns of abnormal brain activity
- possible ethical issues are raised; to what extent does the prisoners have the agency to give their informed consent, they may feel obliged to take part simply because they are bored
