Raine

• Methodology - quasi experiment, matched pairs, each murderer with a non-murderer of the same sex and age, used PET scans, between murderers and non murderers, opportunity sampling, 41 participants, 39 male and 2 female, all had mental impairments such as SZ, all pleaded NGRI, at university of california for PET scans NGRI defence or to reduce sentence if already found guilty.
• Procedure - 10 mins before FDg injection ppts given practise trials on a continuous performance task, 30 seconds before injection task started so inital task novelty did not affect the results of experiment (PET scan). FDG injected into each ppt. FDG taken by brain for 32 min period where ppt completed a continuous performance task, ppt then transferred to PET scanner in the brain 10 mm horizontal slices were scanned of brain.
• Findings - 41 murderers had significantly lower glucose metabolism in several brain areas, in the pre-frontal cortex (linked to impulse control) the corpus callosum (transfer brain signals from one hemishere to another) the left angular gyrus (cognitive deficits. Murderes showed abnormal asymmetry of activity with reduced left and increased right activity in the amygdala and hippocampus compared to the control group. Murderers showed significantly higher occipital lobe glucose metabolism than control group.
• Findings 2 - No significant differences between midbrain and groups did not differ on behavioural performance on continuous performance task. Left handed murderers showed less asymmetry and higher prefrontal cortex activity than right handed murderers. Ethnicity had no effect on brain activity. 23 murderers had previous head/brain injuries but this did not affect brain activity significantly.
• Conclusions - His findings support previous research which links certain brain areas to aggression/violence. Findings cannot be taken to demonstrate that violence is determined by biology. Social, psychological, cultural and situational factors also play important roles in predisposing to violence. Data doesn't show murderers pleading NGRi are not responsible for their actions or that PET scans can be used as a diagnostic technique, not establishing a casual link between brain dysfunction and violence cannot be generalised from NGRI murder cases to other violent offences.
• Evaluation - method and procedure - strength - objective study, used PET scans, got a detailed study of brain so could find genuine differences, increases internal validity.
• Evaluation - method and procedure - strength - matched pairs based on age and mental disorder and gender, any differences due to NGRI or control group not individual differences.
• Evaluation - method and procedure - weakness - internal validity issues, quasi experiment, no casual conclusions between brain abnormalities and violent behaviour. No control over the IV so lacks internal validity.
• Evaluation - method and procedure - weakness - issues with the sample as only used 41 murderers who pleaded NGRi so the sample was limited, not representative so reduces the population and external validity as researched can't be generalised.
• Evaluation - findings and conclusions - weakness - don't know causation, quasi experiment so doesnt allow for casual conclusions to be drawn between brain activity and violent behaviour. The IV is pre-existing so no control over it and lacks internal validity as other factors such as upbringing affect the research.
• Evaluation - findings and conclusions - weakness - alternative evidence to contradict Raine, Bobo doll study shows aggressive behaviour and then it is replicated so not a biological reason to be aggressive.
• Evaluation - findings and conclusions - strength - high internal validity as using PET scans can be objective and detailed study of brain activity increases internal validity.
• Evaluation - findings and conclusions - strength - high internal validity as used matched pairs based on age, mental disorders and gender so an increases the internal validity.
• Evaluation - ethical and social implications - strength - Raine gained consent as they agreed to the PET scans so it is ethical. But some argue that as they are NGRI it is not full valid consent.
• Evaluation - ethical and social implications - weakness - the legal system, juries considering brain scans, not suggesting that murderers are not responsible for actions and could have negative implications for society if not regulated properly.
• Evaluation - ethical and social implications - weakness - the legal system, punishment system so alternative interventions and rehabilitation programmes needed for ppts.