Classic study - Raine et al. (1997) Flashcards
What were the 2 aims of Raine et al’s classic study?
To examine whether there was a difference in brain functioning between NGRI murderers and control non-murdering participants
To see whether there was any evidence of diminished mental capacity in NGRI criminals which may have implications for sentencing received
What are the IV and DV of Raine et al’s classic study?
IV: Type of participant - experimental group of people charged with murder but pleading NGRI or control group of non-murderers
DV: Brain dysfunction indicated by glucose metabolism measured using a PET scan
Who were the participants of Raine et al’s classic study? (3 points)
82 participants in total
Experimental group: 41 participants (39 males and 2 females)
Control group: 41 participants (same sex)
What were the experimental design and methodology of Raine et al’s classic study?
Experimental Design: matched pairs based on age and gender
Methodology:
Experiment type: Natural quasi-experimental - brain damage was naturally occurring
Location: UC Irvine imaging room
What was the procedure of Raine et al’s classic study? (4 steps)
- Participants did a 10-minute practice CPT (Continuous Performance Task) to ensure they were familiar with and understood the task
- All participants were injected with a (FDG) fluorodeoxyglucose tracer
- All participants performed a CPT for 32 minutes whilst undergoing a PET scan
- The “cortical peel” and “box” techniques were used to analyse the 10 slices (pictures) taken of the participants’ brains, comparing activity in the right and left hemispheres
What were the results of Raine et al’s classic study? (4 points)
Abnormal asymmetries with reduced activity in areas of the left hemisphere and increased activity in the right hemisphere
Glucose metabolism in:
Left-hemisphere pre-frontal regions
NGRI: 1.09
Control: 1.12
Amygdala in left hemisphere
NGRI: 0.94
Control: 0.97
Some brain areas showed no difference - cerebellum and midbrain; associated with mental illness, not violence
What is the significance of the results of Raine et al’s study? (2 points)
Pre-frontal cortex
+ Typically regulates decision-making and moderates social behaviour
+ Impairment could lead to impulsive behaviour and a loss of control
Amygdala
+ Involved in regulating emotions and detecting fear
+ Underactivity could explain unusual emotional responses in NGRI participants like a lack of fear
What was the conclusion of Raine et al’s study? (3 points)
Multiple brain areas are involved in regulating aggressive behaviour including:
+ Prefrontal cortex
+ Corpus callosum
+ Amygdala
+ Hippocampus
Brain abnormalities in such regions combined with environmental and social factors can predispose a person to violent and aggressive behaviours
No differences in CPT based on age, gender, ethnicity, or history of brain injury
How generalisable is Raine et al’s classic study? (3 points)
Low generalisability
Unique sample of NGRI patients committing murder - not representative of other crimes e.g. theft
Androcentric experimental group - 39 males and only 2 females
How reliable is Raine et al’s classic study? (3 points)
PET scans can be repeated for reliability by other researchers to check for consistency in data and compare results
Standardised procedure (e.g. CPT for 32 minutes with 10 minutes of practice) can be replicated
Lowered reliability:
+ 1990s PET scans were unclear and had to be interpreted
+ + Subjectivity based on researchers’ interpretation
Is Raine et al’s classic study applicable to real life? (2 points)
Has implications for the wider world where lawyers can advocate for lighter sentencing as violent criminals plead NGRI
Could be considered a socially sensitive research area if used to screen and criminalize people
How internally valid is Raine et al’s classic study? (2 points)
Matched pairs design was used to match NGRI participants with control group - greater control over extraneous variables
Medication being withheld means that the PET scan measures ‘natural’ brain activity - cause and effect between brain activity and NGRI status can be established
How ecologically valid is Raine et al’s study? (2 points)
All participants underwent a PET scan that involved an individually moulded thermosetting plastic head holder used to hold the head still whilst 10 slices of the brain were taken at 10mm intervals
Such experimental procedures used at the Irvine (UCI) imaging centre lack task validity - unreflective of real-life violent crime involving NGRI people
How ethical is Raine et al’s classic study? (3 points)
Protocols and consent forms approved by the Human Subjects Committee of UC Irvine were used - included protection from harm and informed consent
Participants were taken off their medication for 2 weeks - could have had adverse side effects including withdrawal symptoms like hallucinations and delusions, subjecting participants to distress
Exposure to the harmful radioactive isotope FDG in PET scan could be harmful
