Raine et al (1997)
- Created by: Mbegum
- Created on: 29-12-18 16:35
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- Raine et al (1997)
- Methodology
- Overall
- Quasi-experiment
- matched pairs design
- IV = NGRI or not
- DV = brain difference
- experimental group
- 39 M + 2F
- mean age = 34.3
- all charged w/ murder or manslaughter
- pleaded not guilty by reasons of insanty
- referred to uni of California for evidence of NGRI
- referred on basis of mental impairment
- e.g scz + head injury
- referred on basis of mental impairment
- medication free
- checked via urine scan 2 weeks prior to brain scans
- 39 M + 2F
- control group
- each murder matched w/ normal indiv via age + sex
- scz = matched w/ scz from mental hospital
- medication free
- each murder matched w/ normal indiv via age + sex
- Overall
- Procedures
- opportunity sampling
- PET scans
- study active brain
- injected FDG tracer
- tracer taken up by active areas of brain
- therefore can compare betw/ NGRI / not
- tracer taken up by active areas of brain
- Continuous performance task
- activates target areas of brain
- therefore investigate how diff areas func
- activates target areas of brain
- process
- practise CPT before FDG
- 30sec before FDG = start CPT
- therefore initial task novelty = not FDG labelled
- 32min after FDG injected = PET scan done
- 10 horizontal slices via cortical peel + box technique
- Findings
- Brain differences
- reduced activity in NGRI = areas prev linked to violence
- prefrontal cortex
- left angular gyrus
- corpus coallosum
- left hemis of amygdala + thalamus + hippocampus
- increased activity in NGRI = areas not prev linked to vio
- cerebullum
- right hemis of amygdala + thalamus + hippocampus
- no difference in NGRI + cotrol = in areas not prev linked to vio
- caudate
- putamen
- globus pallidus
- midbrain
- reduced activity in NGRI = areas prev linked to violence
- Performance on CPT
- both groups = similar performance on CPT
- therefore any nrain diff = not related task related
- both groups = similar performance on CPT
- uncontrolled differences
- handedness
- 6 NGRI = left handed
- less amygdala assymetry VS right hand
- 6 NGRI = left handed
- ethnicity
- 14 non-white NGRI
- no s.f diff in brai activity
- 14 non-white NGRI
- head injury
- 23 NGRI = history of head injury
- no diff
- 23 NGRI = history of head injury
- handedness
- Brain differences
- Conclusion
- Overall
- This research + past research
- preliminary evidence for NGRI having diff brain func VS normal indiv
- neural processes unferlying violence
- complex + can't be reduced to single brain mech
- vio behav explained via disruption in network of interacting brain mech
- disruption = causes predisposition + not cause
- This research + past research
- Confounding Variables
- carefully designed
- large sample
- matched controls
- large sample
- head injury + IQ not ruled out as confounding variables
- carefully designed
- warnings
- results do not show
- vio behav = determined by bio alone
- social + psych + cultural factors play a role
- murderers pleading NGRI = not responsible for actions
- PET scan = not a way to diagnose a vio indiv
- brain dysfunction doesn't cause vio
- vio behav = determined by bio alone
- results do not show
- Overall
- evaluation
- methodology & procedures
- quasi experiment
- experiments = has IV + DV
- quasi = IV already existing + not manipulated by researcher
- causal conclusion not justified
- quasi = IV already existing + not manipulated by researcher
- experiments = has IV + DV
- Research Technique
- PET scans
- allow detailed study of different regions of brain whilst in action
- Raine = investigate how diff indiv process different info
- allow detailed study of different regions of brain whilst in action
- PET scans
- The sample
- sample = only of murderers
- not all vio indiv are murderers
- cannot generalise findings to all vio indiv
- not all vio indiv are murderers
- sample = only of murderers
- quasi experiment
- alternative evidence
- Yang et al
- meta-analysis of 43 imaging studies
- found s.f reduced prefrontal cortex activity in antisocial + vio indiv
- meta-analysis of 43 imaging studies
- tiihonen et al
- 895 finnish prisoners
- MAOA gene = causes high levels of dopamine
- link betw/ MAOA gene + increased chance of committing vio crime
- MAOA gene = causes high levels of dopamine
- 895 finnish prisoners
- James Fallon
- had genetic characteric of vio crim
- wasn't ciminal = healthy upbringing
- genes not triggerred via diathesis-stress theory
- wasn't ciminal = healthy upbringing
- had genetic characteric of vio crim
- Yang et al
- ethical issues & socila implications
- valid consent
- sample = NGRI
- mayn't be mentally competent to provide valid consent
- sample = NGRI
- socially sensitive research
- Untitled
- psychological harm
- may not have understood what to do
- may have found CPT hard = lower self-esteem
- PET scan = distressing experience
- may have found CPT hard = lower self-esteem
- may not have understood what to do
- right to withdraw
- prisoners = therefore may not have known about right to withdraw and felt pressured to continue
- valid consent
- methodology & procedures
- Methodology
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