Raine (1997, classic)

• aim?


  investigate using PET brain abnormalities in murderers who plead NGRI
• procedure?

  continuous performance task involving Ps staring at a screen and pressing button when various symbols appear for 10 minutes.

  • radioactive glucose tracer injected into Ps, further 32 mins of task and PET scanned to look at glucose metabolic rate to determine level of activity in regions of brain
• sample?

  2 groups with 41 Ps (39 male 2 female) in each group:

  • experimental group: people who plead NGRI charged with murder/manslaughter and tried in state of Cali, US
  • control group: matched to experimental group from age, sex, psychiatric illnesses (schizo) matched pairs.

  control went through further screening for mental/physical health
• why can this study be referred to as a quasi/natural experiment?


  researchers don't have total control over IV (whether Ps committed manslaughter or not) as group was pre-existing so cannot randomly be placed in conditions of experiment
• cortical results?

  1. lower levels of brain activity in both hemispheres compared to control group of PFC (lateral/medial areas)
  2. lower levels of brain activity compared to control group of parietal cortex

  they inhibit a reactive response to threatening stimuli.
• subcortical area of brain results?

  1. lower levels of brain activity compared to control group in both hemispheres of corpus callosum (allow hemispheres to communicate)
  2. abnormal asymmetrical levels of limbic system activity compared to controls in thalamus(right hemi = higher, left same), amygdala (right hemi = higher, left lower) hippocampus (right hemi = higher, left lower)

  important to note right hemisphere generates negative moods, left regulates said mood

  1. no overall difference in level of activity in lateral temporal lobe between murderers and control group
• conclusions?

  • reduced activity in certain areas of brain (PFC or corpus callosum) with abnormal asymmetries of activity in structures of limbic system (amygdala or hippocampus) could predispose a person toward violent behaviour.
• what are the reasons for the conclusions of Raines study?

  1. lack of functioning in PFC reduced regulating activity of limbic system, less able to control impulsiveness/aggressive response to threatening stimuli
  2. abnormal amygdala functioning (responsible for emotion processing) results in fearlessness so increased chance of violent behaviour
  3. hippocampus/thalamus related to learning, possible abnormal activity = unable to modify wrong behaviour
  4. right hemi = negative mood, regulated by left hemi so may be more violent if in a bad mood
• generalisability?

  • large sample, could give out valid info about type of behaviour emitted from violent offender and can generalise
  • research is mainly androcentric (focused on men, 30 males 2 females) so unlikely to represent females. HOWEVER most violent offenders are males, results may give valid info
  • sample is atypical, consists of certain violent offenders so cannot represent all violent offenders and explain behaviour to wider population
• reliability?

  • high as a whole, standardised and equipment used the same on every participant so replicable. Also used PET scans to produce quantitative data about glucose levels in brain
• applications?

  • useful for society, pre-dispositions for committing violent acts can be identified using PET scan so behaviour can be predicted and prevent any crime
  • cause and effect between brain dysfunction/violent murder is not established, certain kinds of brain activity doesn't mean someone will be a violent offender.
• validity?

  variables well controlled:

  no meds 2 weeks- ensure meds don't influence brain activity, control group matched to experimental with age gender psyc illnesses.

  this means we can be sure any differences are probably not due to individual differences

  however no control for confounding results, no control of upbringing or situation where murder occurred.

  reductionist !only focuses on brain dysfunctions not upbringing but means we can only focus on bio aspect

  PET resolution is lower than other methods, accuracy is lowered
• ethics?

  • research approved by ethics committee, guidelines were largely followed (no deception, limit harm to Ps)
  • consent given but are Ps fully aware of implications of consent? some suffer illnesses like schizo. murderers also took part in research to build up case for NGRI plea, so under pressure to take part from counsel.
  • Ps not always protected from harm, eg no meds 2 weeks, PET= injection.
  • problems may be outweighed due to hope for pleading NGRI, escaping death penalty :)