raine et al

Question 1

aim

Answer 1

• to show the brains of murderers that plead not guilty by reason of insanity were different from the brains of non-murderers
• he hypothesised that violent people would have localised brain dysfunctions in the PFC, amygdala, thalamus, hypothalamus, corpus callosum and the angular gyrus

Question 2

sample

Answer 2

• 41 murderers (39M, 2F)
• 41 matched controls
• 6 murderers with sz were matched on age and sex
• normal controls were screened using physical exams, medical history and psychiatric interviews
• controls with any history of seizure disorders, head trauma and substance abuse were excluded

Question 3

procedure

Answer 3

1. sample mark
2. talk about how they were screened
3. all offenders were kept in custody and medication free for 2 weeks
4. ppts were required to complete a degraded stimulus version of a CPT, which lasted 32 mins
5. CPT consisted of pressing a button each time a target was spotted on the screen
6. CPT increased glucose metabolism in the frontal lobes
7. CPT started 30 seconds before the FDG injection so initial task novelty would not be FDG traced
8. the FDG injection, which is a radioactive tracer, was injected to trace glucose metabolism
9. ppts were scanned using PET scans to image brain functioning
10. their brains were scanned 10 times at 10mm intervals to pick up different gluocose metabolisms in the cerebral cortex and subcortical layers
11. brain regions were identified using the cortical peel (lateral areas) and box technique (medial areas)

Question 4

results

Answer 4

• murderers had higher levels of brain activity in the right hemisphere in the right amygdala compared to non-murderers (0.88 vs 0.83), so they had limbic system abnormalities

-murderers has lower levels of brain activity in the left hemisphere in the corpus callosum compared to non-murderers (0.68 vs 0.56)

Question 5

conclusions

Answer 5

• the brains of murderers pleading NGRI are different from the brains of non-murderers
• deficits in the PFC can cause impulsivity, lack of self control, immaturity leading to aggressive acts

Question 6

strengths

Answer 6

high val, large sample size
high reliability

Question 7

weaknesses

Answer 7

Lacks mundane realism as the task was a CPT that took place for 32 minutes and consisted of pressing a button each time a target was detected on a screen. This task has no direct correlation to aggression, murder or violence. Therefore, the CPT is not representative of the murderers brain activity when they were committing the crimes. The findings of if murderers pleading NGRI are different to non-murderers may not represent how criminals behave in real life.

Lacks validity, as the ppts were scanned using PET scans to produce an image of brain functioning so they could look at brain activity. This could have been a stressful experience and the murderers may not have been that still during the actual crime which could have affected the brain activity observed so the results may not be representative of the brain activity the murderers had when committing their crime.

Question 8

application

Answer 8

High application to society as we can pre-screen people to test for deficits in brain areas like the PFC, amygdala and corpus callosum to provide treatments to prevent people from going on to commit crimes or to stop people from re-offending. For example, murderers has lower levels of brain activity in the left hemisphere in the corpus callosum compared to non-murderers (0.68 vs 0.56). Reduced brain activity in certain areas may act as a predisposition for violence so violent criminals may therefore be less accountable for their actions which may have importance when sentencing is decided.