Raine et al - classic study

Question 1

Aims

Answer 1

• Whether muredres pleading not guilty by reason of insanity had brain dysfunction in areas linked to violence
• hypothesis to find evidence of dysfunction in the prefrontal cortex//limbic system// corpus callosum.

Question 2

Method

Answer 2

• Lab design, independent measures
• Experimental sample : 4 murders - avg age 34,, 39 men & 2 women,, 6 had sz//23 head injuries//rest some form of brain dysfunction.

Question 3

Procedure

Answer 3

• Controls : med free for 2 weeks
• IV : whether the participant had committed murder/ manslaughter or not.
• DV: results of PET scans
• Given practise trial of the task for 10 mins, then injected w FDG tracer.
• Continuous performance task, consisted of spotting targets on screen & pressing button to indicate target for 32 mins.
• PET scans measured glucose metabolism.

Question 4

Results

Answer 4

• Lower levels of brain activity in both hemispheres compared to the control group in the Prefrontal Cortex - Lower levels of brain activity compared to the control group in various areas of the parietal cortex
• Lower levels of brain activity compared to the control group in both hemispheres in the Corpus Callosum
• There were abnormal asymmetrical levels of limbic system activity (RH higher than controls LH lower) compared to the controls in the: Amygdala, Thalamus and Hippocampus

Question 5

Conclusions

Answer 5

• Results could predispose a person towards violent behaviour.
• Abnormal functioning of the amygdala, which is responsible for emotional processing, results in the murderers being fearless. This fearlessness could result in the increase chance of acting violently.
• The hippocampus and thalamus have been related to learning and it is possible that abnormal activity here could result in criminals being unable to modify their own behaviour by learning form the consequences of their actions
• 4. Raine et al. suggest that the right hemisphere is implicated in generating negative mood. This is normally regulated by the left hemisphere. However, because the corpus callosum is not as active in murderers compared to controls, they would be unable to regulated the negative mood and possible become more violent due to the low mood.

Question 6

Generalisability

Answer 6

• Low : limited sample
• High : Reasonable gen within target pop

Question 7

Reliability

Answer 7

• High: standardised PET scan proc//Quantitive data

Question 8

Validity

Answer 8

• High : internal validity as PET objective
• Low : ecological as ppts preforming irrelevant CPT task

Question 9

Applications

Answer 9

• Useful in understanding criminal behaviour, identifying brain abnormalities could lead to early intervention.

Question 10

Ethics

Answer 10

• High : Approved so guidelines were upheld: consent, limited harm (only one injection)
• Low : Had to be off meds (schizophrenic)
• LOW: Pressure as part of the NGRI plead (also +)