Raine et al Flashcards
What is the research method?
Quasi-experiment
Bcs the experimenters could not manipulate the independent variable- it was naturally occurring
A person was a murderer or they were not a murderer
What experimental design is used?
Matched pair design
Participants matched on age and gender
The six schizophrenics in the experimental group were matched with six schizophrenic controls (non-murderers) This gave an accurate comparison between the NGRI’s and the others
Who were the participants?
In the experimental group, there were 41 murderers (39 men and 2 women) who had a mean age of 34.3.
They had all been charged with murder or manslaughter and all pleaded NGRI. They were referred to the University of California for examination to obtain proof of their diminished capacity.
The control group was formed with the matched pairs design.
None of the participants were taking medication.
What was the independent variable?
The Independent Variable was whether the participants were a criminal who had plead NGRI or someone who had not been accused of a crime.
What was the dependant variable?
The dependent variable was whether the participant showed evidence of brain dysfunction in their prefrontal cortex and other areas such as the angular gyrus, amygdala, hippocampus, thalamus, and corpus callosum.
What was the sampling method?
Opportunity sampling
What is opportunity sampling?
Opportunity sampling uses people from the target population available at the time and willing to take part
What apparatus was used?
A thermoplastic head holder that was individually moulded to hold the participant’s head still while being scanned.
A PET machine to image brain functioning.
FDG tracer injected to trace brain metabolism.
A continuous performance task (CPT) which required participants to detect target signals for 32 minutes. This is a task that had been shown to make the frontal lobes work especially hard, together with the right temporal and parietal lobes, so that the investigators could see how the different areas functioned.
What were the control measures? (3)
All of the murderers were kept in custody and were medication-free for two weeks prior to the brain scanning. All of the non-murderers were also not taking any medication.
Ten minutes before receiving the FDG injection, participants were given practice trials on the CPT.
30 seconds before the FDG injection, participants started the actual CPT so that the initial novelty wouldn’t be FDG labeled and to get their brains ’working’.
How was the data collected?
Thirty-two minutes after the FDG injection a PET scan was done of each participant. Ten horizontal slices (pictures) of their brain were recorded using the cortical peel and box techniques.
