Raine(1997) Classic Study Flashcards
What was the aim?
To see if there was a difference between murderers who pleaded not guilty by reasons of insanity and non-murderers
What was the independent variable?
Whether the participant is an offender pleading not guilty by reasons of insanity (NGRI) to murder, or a non-murderer in the control group
What is a confounding variable?
A variable that effect other variables in a way that produces spurious or distorted associations between two variables
How many participants?
How many were violent criminals and how many in the control group?
- 82 overall in the study
- 41 violent criminals and 41 controls
What was the average age of the participants in the study?
34.3 years old
6 people from each group had which mental illness?
Schizophrenia
What was the number from each gender in the NGRI group?
39 men and 2 women
23 of the NGRI group had what?
Brain damage
How many of the NGRI group had a history of drug abuse?
3
2 of the NGRI group had…?
Epilepsy
7 of the NGRI group had…..?
Emotional or learning disorders
What were the controls of the study
People of the same age and sex with no history of crime or mental illness, except 6 controls who had schizophrenia
What should the NGRIs be described as?
An opportunity sample
What is the procedure?
- Tested at the university of California
- Each participant was injected with a glucose tracer and then performed the Continuous Performance Task (CPT) for 32 minutes.
- Then the PET scan was carried out
What were the experimental controls Raine used in his procedure? (2 examples)
- The participants were allowed to practice the CPT ten minutes before the glucose tracer was injected to make sure they were equally familiar with it
- He made sure none of the participants (NGRIs or controls) were on medication; the NGRIs had been kept medication free for 2 weeks before the PET scan
3 strengths of the study are….?
- Largest sample yet subjected to brain imagery for this purpose
- Includes control group
- Looks at different areas of the brain associated with aggression
3 weaknesses of the study are….?
- The findings only appliaple to this group of murderers pleading NGRI, not to all violence/aggression
- Doesn’t show the cause of these brain deficits
- The PET images are not particularly clear
What were the 2 main areas in the NGRI groups brain that showed less activity?
What are each of those areas functions?
The frontal lobe - associated with rational thinking, self-restraint and memory
The parietal lobe - associated with abstract thinking such as “morality” or “justice”
Correlation=?
Relationship NOT cause
Where in the sub-cortical region did the NGRIs have less activity?
The corpus collosum
What is the role of the corpus collosum?
Long term planning- it is the “bridge” of merge fibres connecting the brains two hemispheres
Was there more or less activity on the right side on the amygdala, thalamus and MTL/hippocampus?
More on the right and less on the left
What do the amygdala, thalamus and MTL/hippocampus have in common? (CLUE: when there is more activity on the right side what happens)
When there is more activity on the right side, these are the areas of the brain that are associated with aggression in animals.
What can prefrontal deficits do?
They might make someone more impulsive and emotional
What can deficits in the lambic system do?
They might make someone aggressive, find it hard to learn from their mistakes or understand their emotions
What do deficits in the corpus collosum do?
They make it harder for the brains hemispheres to communicate, making it difficult to think through long term consequences and make decisions
What do deficits in the parietal lobe, amygdala and hippocampus cause?
They can make it harder for someone to judge social situations, leading them to overreact
What is a PET, what does it do and how?
It scans brain activity
It looks at levels of neurotransmission in the brain
It involves injecting the participant with a glucose solution that dissolves in blood. This glucose solution has been “tagged” with radioactive tracer which will make it’s way to the brain. This takes around 30 minutes
