Biological Psych: Classic Study - Raine et al (1997)
- Created by: laurenherpe
- Created on: 07-01-18 15:33
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- Raine et al (1997)
- Aim
- to find out which brain areas were dysfunctional in violent offenders
- using PET scans
- to find out which brain areas were dysfunctional in violent offenders
- Sample
- 41 criminals with murder/manslaughter convictions
- 10 had schizophrenia
- 23 had brain damage/head injury
- all tested to gain evidence to support NGRI
- Control group
- matched pairs
- age
- gender
- psychiatric illness
- matched pairs
- 41 criminals with murder/manslaughter convictions
- Lab experiment
- IV
- whether they had committed murder/manslaughter or not
- DV
- results of PET scans
- IV
- Procedure
- 1. P's performed continuous performance task (CPT)
- stare at screen, blurred symbols appear
- press button when certain symbol appears
- constant attention (10 mins)
- 2. Radioactove glucose traker injected
- flurodeoxyglucose
- 3. Brains PET scanned
- After 32 mins of task
- to look at glucose metabolic rate in brain
- to look at level of activity in brain areas
- 1. P's performed continuous performance task (CPT)
- Results
- NGRI group had brain dysfunction in areas previously related to violent behaviour
- Lower levels of brain activity compared to control group in
- Cortical brain areas
- Prefrontal Cortex
- lateral prefrontal
- medial prefrontal
- Prefrontal Cortex
- Subcortical brain areas
- in both hemispheres in corpus callosum
- Cortical brain areas
- abnormal asymmetrical levels of limbic system activity compared to controls in
- Thalamus
- right hemisphere higher than controls, left hemisphere same
- Amygdala
- right higher, left lower
- medial temporal lobe
- right higher, left lower
- no overall diff in level of activity in amygdala, temporal lobe and thalamus
- Thalamus
- Conclusions
- lack of functioning in PFC results in reduced ability to regulate the activity of limbic system
- so less able to control impulsive and aggressive responses to threatening stimuli
- abnormal functioning of amygdala results in murderers being fearless
- increased chance of acting violently
- hippocampus and thalamus related to learning.
- abnormal functioning - criminals unable to modify own behaviour by learning from actions
- right hemisphere could negative mood.
- normally regulated by left hemisphere
- corpus callosum not as active in murderers compared to controls
- unable to regulate negative mood and could become more violent
- corpus callosum not as active in murderers compared to controls
- normally regulated by left hemisphere
- lack of functioning in PFC results in reduced ability to regulate the activity of limbic system
- Aim
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