Biological - Raine et al. (1997)

Question 1

Aim of Raine

Answer 1

To find out if there is a difference in the structure of brain activity between people who have committed murder (NGRIs) and non-murderers.

Question 2

What is NGRI

Answer 2

Not Guilty by Reason of Insanity

Question 3

Independent variable - Raine

Answer 3

Whether participant is an offender pleading NGRI to murder or a non-murderer in a Control group

Question 4

Dependent variable - Raine

Answer 4

Relative glucose levels in the prefrontal cortex, the other lobes of the brain, the corpus callosum, the amygdala, the hippocampus and thalamus as revealed through PET scans

Question 5

Experiment design

Answer 5

(Seems like matched pairs, but Raine didn’t pair each participant’s results up with the other group)
Independent groups design

Question 6

Sample - Raine

Answer 6

Opportunity sample (not control group)
41 offenders pleading NGRI to murder
- 39 men, 2 women
- 23 have history of brain damage, 3 with drug abuse history, 6 suffered from schizophrenia, 2 with epilepsy and 7 with other emotional or learning disorders
41 control participants
- same age and sex with no history of crime or mental illness
- 6 controls had schizophrenia

Question 7

Procedure - Raine

Answer 7

Tested at University of California. Each injected with glucose tracer and performed Continuous Performance Task (CPT) for 32 minutes.
Then the PET scan was carried out

Question 8

Experimental controls used during procedure - Raine

Answer 8

• participants allowed to practice the CPT 10 minutes before glucose tracer injected (to make sure they were all equally familiar)
• made sure none of the participants were on medications; NGRIs kept medication-free for 2 weeks before PET scan

Question 9

Cortical regions findings - Raine

Answer 9

Murderers had significantly lower glucose metabolism (less activity) in cortical regions (lateral and medial prefrontal areas, etc.
Murderers showed higher metabolism than controls in the occipital lobe, a brain area not previously linked to violence

Question 10

Subcortical regions findings - Raine

Answer 10

Murderers had lower glucose metabolism in the corpus callosum, left amygdala and left medial temporal lobe (including hippocampus)
Murderers had greater activity in the right amygdala, the right medial temporal lobe and the right thalamus

Question 11

Conclusion - Raine

Answer 11

Hypothesis was supported.
Findings show that murderers pleading NGRI have different brain activity than those who aren’t violent offenders.
Concluded that dysfunctions of a single brain area cannot explain violent behaviour. Likely explanation is that network of interacting brain areas are the reason + social, environmental and psychological factors

Question 12

High generalisability - Raine

Answer 12

Used a large sample of 82 participants.
Anomalies like participants with unusual brain structure would not skew the data too much
Makes results representative for a wider population

Question 13

Low generalisability - Raine

Answer 13

NGRIs are unusual offenders, they could have killed someone but don’t remember doing it or too confused to stand trial.
Not representative of “typical” murderers

Question 14

High reliability - Raine

Answer 14

PET scans: a reliable brain imaging technique which has been used since the 1970s. Objective and replicable results, it can also be re-tested to check its reliability
Standardised procedure: CPT ensures that all participants were concentrating on the same thing, ensures that they all had similar types of brain activity

Question 15

Low reliability - Raine

Answer 15

Raine admits that there were still problems with the reliability of PET scanning in the 1990s. Results were sometimes unclear and had to be interpreted which may make it subjective

Question 16

Application - Raine

Answer 16

To be cautious of biological evidence
Suggests that particular brain structures can can be identified that cause aggression.
This aggression can be ‘treated’ by changing biological structures through medication or surgery.
However, this is only a partial explanation, there are other factors which may affect aggression.

Question 17

High validity - Raine

Answer 17

Bufkin & Luttrell (2005): meta-analysis where they analysed results of 17 studies which used brain imaging to study aggression in humans. Found all studies point to similar conclusions - impulsivity is linked to deficits in the prefrontal cortex or the amygdala, adds to the construct validity of Raines study
High degree of control: participants matched across the experimental and control groups on 3 potentionally confouncing variables. Standardised procedures used with all participants (e.g. same CPT for all participants for 32 minutes), PET scans had same protocol, etc. high internal validity as potentionally confounding variables were controlled

Question 18

Low validity - Raine

Answer 18

Ecological validity: CPT used by Raine criticised for being artificial and unconnected to violence or provocation. Participants doing unusual task and in an unusual state of mind when PET was carried out
Natural experiment: doesn’t show cause-and-effect. E.g. NGRIs might have developed brain deficits after the killing
Reductionist: only looks at brain activity (Raine made this point as well), other studies e.g. Brengden or Bandura suggests other conclusions, not just brain activity

Question 19

Ethical considerations - Raine

Answer 19

Consent: NGRIs agreed to have PET tests since it would help their court case. Control participants all gave prior consent. If NGRIs were not competent to consent, presumptive consent given by lawyer or carer

Question 20

Ethical issues - Raine

Answer 20

Risk: participants have to be injected with a radioactive tracer for PET imaging. NGRIs were to undergo this anyways, but for control participants, this may be an unnecessary medical procedure which increases the risk of research
Conclusion: seems to suggest that people are driven to kill by their brain structure and that their violence is out of control. This may lead to people screening job candidates, partners, etc. so they don’t have a “murder’s brain”, this goes against the social responsibility of ethical research