evaluation

• PET scans allow for objective and detailed study which increases internal validity and the findings represent genuine differences
• quasi- experiment do not allow causal conclusions to be drawn as there was a pre-existing difference and no control over IV or cofounding variables which lowers internal validity
• study is replicable as the PET scans can be repeated and the procedure was standardised so it can be checked for consistent results which increases external validity
• used matched pairs design on key variables so raine can assume any difference is due to NGRI or control rather then individual differences which increases internal validity
• issue with the sample - only 41 murderers pleading NGRI in California so its limited and may not be representative of all violent individuals which reduces population validity as it cant be generalised
• Bandura - bobo doll experiment found that children who observe aggressive role models were more likely to imitate the aggressive behaviour which suggest violent behaviour is learnt rather a biological pre-disposition
• Coccaro - people with IED showed increased amygdala activity which supports Raines findings
• raine gained valid consent - the murderers agreed to support their plea and the university approved the study in line with APA ethical guidelines
• the research could have caused stress and anxiety as it involves invasive procedures like the FDG injection and PET scanning machines
• research is socially sensitive and findings could be misinterpreted by labelling people with brain dysfunctions as murderers or using brain scans as a way to diagnose violent behaviour while raine was clear his study did not mean those things
• raines findings may affect the punishment systems as if violent behaviour is linked to brain activity then alternative interventions to prison may be needed
• negative implications to society is brain scans in the legal system were not regulated properly as brain normalities are a pre-disposing factor only