raine et al

• aim

  . study brain activity in NGRI killers by using PET scans
• hypothesis


  NGRI killers will show abnormal activity in brain areas associated with violence
• what are the brain areas associated with violence

  prefrontal cortex, amygdala, hippocampus, thalamus
• method - groups


  2 - experimental and control
• how many ppts in each group

  41
• how many males and females

  39 males, 2 females
• how many schizophrenic in each group

  6
• how were ppts 'matched'

  age and gender
• why is the experiment not matched pairs design


  ppts weren't matched on all factors
• what is the experimental design

  independent groups
• what type of sample was used

  opportunity
• procedure


  1 - ppts injected with PET radioactive tracer

  2 - completed a continuous performance task (identifying targets on a screen and pressing a button) for 32 minutes

  3 - had PET scan conducted
• results

  NGRIs had:

  . lower brain activity in corpus collosum, left amygdala, left temporal lobe including hippocamps

  . NGRIs had higher activity in right amygdala, right temporal lobe, right thalamus
• conclusion


  . there is a link between brain structure and aggression

  . murderers have impaired function in brain areas previously identified as involved in violence

  . dysfunctions of a single brain area cannot explain violence on its own
• evaluation - generalisability strength

  large sample size, 41 in each condition = more likely to be representative of NGRIs
• evaluation - generalisability weakness

  sample only consisted on NGRIs = can't be generalised to other types of offenders and can't explain aggression in general population
• generalisability - so what

  not particularly generalisable as not representative of wider population so further research is required to look at aggression in other people
• reliability strength


  standardised procedure used - PET scans = objective measure, drug free for 2 weeks = consistency across both groups = high internal reliability
• reliability weakness


  researchers stated there may be differences in the procedure based on the images taken - different locations based on landmarks within each individual brain
• reliability so what


  while there may be strong internal reliability due to use of PET scans, external reliability may have been affected
• application of study


  1 - scans can be used to inform decisions on sentencing of prisoners

  2 - may be possible to predict who may be predisposed to commit violent offences so interventions can be put in place

  3 - inform which treatments may be most effective to someone
• validity strength


  high degree of control - ppts matched across both groups eg ages, mental health conditions = some extraneous variables controlled = high internal validity
• validity weakness


  extraneous variables eg social and situational factors (contrived setting, emotions) could have affected findings = difficult to establish cause and effect - hard to say whether brain abnormalities directly caused aggression
• validity so what


  controlled procedure used in lab exp gives high objectivity and internal reliability however ecological validity of findings may be compromised by ignoring emotional and situational factors = weaker
• ethics weakness


  1 - sanity of NGRIs is questionable = can't gain direct informed consent

  2 - socially sensitive = suggests it is in peoples nature to kill so they aren't responsible for crimes, may label people who have same brain structure as murderers despite them never commiting a crime
• ethics so what


  although not particularly ethical the findings were important for research and beneficial for society so this outweighs the ethical implications