Raine - Classic study 1997

What did Raine hypothesise?

• Murderers will show brain deficits/dysfunction in brain areas associated with violence and aggression.

What was the aim of the study?

• To investigate if there is a difference in the structure of brain activity between people who have committed murder (NGRIs) and non-murderers.

Who were the participants?

• 41 murderers, 41 controls.

• 39 men 2 women each.

• mean age 34.3

What types of brain damage did the experimental group have?

• History of head injury or organic brain damage (23 cases)

• Drug abuse (3)

• Schizophrenia (6)

• Epilepsy (2)

• Emotional or learning disorders (7)

• The controls were people the same age and sex with no history of crime or mental illness, except controls who had schizophrenia.

What type of sample was used?

• NGRIs were an opportunity sample.

• Raine was restricted in who was available at the time.

• Opportunity sample would have been gained through speaking to their lawyers.

• Raine does not describe how the control group was recruited - so may be considered to be an opportunity sample too.

What is the IV of the study?

• Whether the participant is an offender pleading NGRI to murder, or non murderer in the control group.

What is the DV of the study?

• Brain activity (glucose level changes) identified by PET scans.

What kind of experiment is the study?

• It is a natural experiment.

• Because we cannot manipulate the IV as brain damage was pre-existing.

What kind of design was used?

• Technically it is an independent measures design, even though Pp were matched with controls, there was a different number in each group.

What was the procedure and experimental controls?

• The participants were tested at the University of California.

• Each was injected with the glucose tracer and then performed the continuous performance task (CPT) for 32 minutes. - Then the PET scan was carried out.

• Raine used other experimental controls:

• The Pp were allowed to practice the CPT 10 minutes before the glucose tracer was injected to make sure they were all equally familiar with it.

• Raine made sure none of the Pp’s (NGRIs or controls) were on medication - the NGRIs has been kept medication free for 2 weeks before the PET scan.

What were the results in relation to the frontal lobe?

• NGRIs showed less activity in the frontal lobe - especially in the prefrontal cortex which is associated with rational thinking, self-restraint and memory.

What were the results in relation to the parietal lobe?

• There was also less activity in the parietal lobe.

• Which is associated with abstract thinking (such as ‘morality’ or ‘justice’ but more activity in the occipital lobe (vision)

• Murderers can lack a moral compass

What were the results in relation to the corpus callosum?

• In the sub cortical region, NGRIs has less activity in the corpus callosum: the ‘bridge’ of the nerve fibres connecting the brains two hemispheres (associated with long-term planning)

• Difficulty with thinking about the consequences of their actions.

What were the results in relation to the amygdala?

• There was an imbalance of activity between the left and right hemispheres in the limbic system.

• There was less activity on the left and more on the right in the amygdala and MTL/hippocampus.

• The amygdala and thalamus are areas of the brain associated with aggression in animals.

What were the results in relation to the thalamus?

• There was more activity on the right side of the thalamus.

• The amygdala and thalamus are areas of the brain associated with aggression in animals.

How are these brain deficits linked to aggressive behaviour?

• Lack of activity in the pre-frontal cortex - more impulsivity.

• Deficits in the amygdala - difficulty in controlling urges/desires.

• Deficits in the thalamus/hippocampus - cant learn from mistakes.

• Deficits in the corpus callosum - difficulty with decision making.

• Deficits in the parietal lobe - difficulty reading social situations leading to overreacting.

What did Raine conclude overall?

• Participants who were found NGRI had a clear difference in brain areas linked to aggression in comparison to controls.

What are the evaluation points for Generalisability? - A03

• NGRIs are unusual offenders, they are people who have killed someone, but either don’t remember doing it or are too confused to stand trial. - these people aren’t representative of ‘typical’ murderers, still less of typical violent individuals. Raine pointed out, not all NGRIs killed their victims violently.

• The sample may be classed as gender bias as a majority of the participants were male, however the number of the male and female convicted of such crimes is disproportionate anyway, so this is not directly a critique of Raines sample.

• We do not want to try and generalise results to wider populations as we aren’t all murderers.

• The findings are only generalisable to this group of murderers pleading NGRI, not to all violence

• On a positive note, this is the largest sample yet subjected to brain imaging for this purpose.

What are the evaluation points Reliability - A03

• PET scans are a reliable brain imaging technique that has been used (with growing success) since the 1970s.

• It produces objective and replicable results and it can be tested and re-tested to check its reliability.

• Can be checked by other radiographers (internal reliability.) Or procedure can be replicated by other researchers (external reliability.)

• The CPT also ensures that all the participants were concentrating on the same thing, which should ensure they all had similar types of brain activity. - (Good internal reliability)

• Raine admits there were still problems with the reliability of PET scanning in the 1990s.

• The results were sometimes unclear and had to be interpreted, which introduces subjectivity and low reliability.

What are the evaluation points for Application - A03

• Raine is not claiming that PET scanning could identify murderers in advance, nor is he claiming that PET scans could help decide whether or not someone is guilty of murder.

• Raine suggests that if the damage that causes these brain deficits can be prevented, people might be prevented from becoming murderers. - They will not develop murderous predisposition.

• This involves early intervention with at-risk children in school, programmes to steer young people away from drugs and monitoring people who have brain injuries.

• It also may be possible to treat people who suffer from these brain deficits, if the deficient parts can be stimulated. (through drug therapy or counselling)

• Then they might be less likely to engage in impulsive, aggressive behaviour.

• However, it would be extremely unethical to ‘label’ people and suggest that they are going to become violent and potentially offenders.

• The research is correlational, there is no way to ‘prove’ that brain abnormalities ‘cause’ aggression - there are lots of reasons for aggression.

• If you ‘label’ someone and tell them they are going to commit murder you can create a ‘self-fulfilling prophecy’ - where they live up to the label.

What are the evaluation points for Validity - A03

• Brain activity measured with PET scans.

• Strength as it is an objective measure - meaning extraneous variables cannot affect the outcome.

• Researchers made attempts to control extraneous variables such as effects of medication and age - this is a strength because it allows the co-variables to be tested more specifically and try to reduce the impact of extraneous variables.

• The CPT used could be criticised for being artificial and unconnected to violence/provocation.

• Pp were all doing the unusual task and in an unusual state of mind when the PET scan was carried out.

• Lowers the mundane realism because the task is unrelated to violence. Lowers ecological validity because they wouldn’t be in a PET scanner while committing murder.

• As a natural experiment the study cannot show cause and effect.

• For example, the NGRIs might have developed their brain deficits after the killing, because of the stress of the event, their arrest and imprisonment and their coming trial.

What are the evaluation points for Ethics - A03

• Study may be considered ethically problematic as it can be argued that there is a lack of informed consent.

• The murderers took part in the research as a part of building a case that they are NGRI which means they may have been pressures by lawyers.

• And ff they have brain damage, the capacity to fully understand what was being asked and so possibly couldn’t give fully informed consent.

• There are ethical concerns with the conclusions for a study like this. It seems to suggest that some people are driven to kill by their brain structure and that their violence is out of their control.

• Even though Raine made it clear that he was not implying this, once research was released to the public, they would possibly misinterpret these which goes against social responsibility of ethical research.