Raine et al. (1997)

Specification

• Raine et al. (1997) Brain abnormalities in murderers indicated by positron emission tomography.

Aim(s)

The aim of the study was to see whether there was different brain functioning in a group of murderers compared to a control group of participants.

The expectation was that the murderers would show evidence of brain differences in their prefrontal cortex as well as in other areas that are thought to be linked to violent behaviour.

This expectation came from previous research which suggested that:

• Violent offenders had poorer brain functioning

• Damage to the prefrontal cortex was linked to aggression

• Abnormal function of the hemispheres in violent offenders

• Possible dysfunction to the corpus collosum in violent offenders

• The limbic structures (amygdala and hippocampus) are linked to aggression

Procedure

The study examined the brains of 41 people (39 males and 2 females) who were charged with murder (or manslaughter) but pleaded ‘Not Guilty by Reason of Insanity’ (NGRI) and compared them with the brains of 41 control participants.

The murderers had a mean age of 34.3, were not receiving medication at the time of the brain scan (and had been medication-free for two weeks prior), and urine scans supported this.

The control participants were the same sex as the murderers, similar age (mean 31.7), did not take medication, and had no history of psychiatric illness (other than 6 participants with schizophrenia who were compared with murderers diagnosed with schizophrenia).

All participants were injected with a glucose tracer, and were required to work at a continuous performance task (CPT) that was based around target recognition for 32 minutes.

They were then given a PET scan (ten minutes before injection they were given practice trials).

The participants were compared on the level of activity in right and left hemispheres of the brain using two techniques called ‘cortical peel’ and ‘box’. A cortical peel compares the absolute glucose values for each region of the brain that is being scanned, and is expressed as a measure that is relative to other areas within that slice of the brain. The box techniques involves locating the area of specific interest and a region of interest box places on the cortical and subcortical structures at each level of the areas of the brain being studied.

Evaluation

• Participants were matched on age and sex. Using matched pairs design eliminates participant variables such as age to increase reliability of results.

• Used PET scans for brain imaging. PET scans are useful as you no longer have to wait for the person to die to examine their brain, so research is more accurate.

• Studied 41 people charged with murder/manslaughter. There are arguments around how generalisable 41 murderers is to the target population of murderers.

• Pre-scan task was a general activity task. Task validity is reduced as the pre-scan task had nothing to do with the violent behaviour shown by murderers.

• The participants participated under protocols and consent forms approved by the Human Subjects Committee of University of California, Irvine, meaning that participants were protected from harm and gave informed consent.

Past Paper Questions

• State one aim from the classic study by Raine et al. (1997). (1) October 2017

2 Marker

• Explain one improvement that could be made to the classic study by Raine et al. (1997). (2) October 2017

• Explain how the study by Raine et al. (1997) can be improved in terms of validity. (2) June 2019

3 Marker

• Describe the procedure of Raine et al. (1997). (3) June 2019

4 Marker

• Explain one strength and one weakness of the study by Raine et al. (1997). (4) June 2019

8 Marker

• Evaluate Raine et al’s (1997) study into brain abnormality in murderers. (8) June 2016