classic study: raine

Question 1

what is the background of the study?

Answer 1

• looks at people charged with murder and pleading not guilty by reason of insanity to see if there were brain differences that might link to aggressions
• PET scanning was used to look for differences in brain functioning between murderers who pleaded NGRI and a control group

Question 2

what is the aim of the study?

Answer 2

• to see whether there was different brain functioning in a group of murderers to control ppts
• expectation was that the murderers would show evidence of brain differences in their prefrontal cortex as well as in other areas

Question 3

what did the expectation from the aim come from?

Answer 3

• violent offenders had poorer brain functioning
• damage to the prefrontal cortex was linked to aggression
• abnormal function of the hemispheres in violent offenders
• the limbic structures (amygdala and hippocampus) are linked to aggression

Question 4

what is the procedure of the study?

Answer 4

• used PET scans to examine brain of 41 people (39 males and 2 females) who were *charged with murder and were pleading NGRI, and compared them with 41 controls
• all the NGRI were referred to imaging centre for legal reasons, such as to obtain evidence for defence
• reasons for referrals: 6 cases of schizophrenia, 23 cases of head injury or organic damage, 3 cases of drug abuse, 2 cases of affective disorder, 2 cases of epilepsy, 3 cases of hyperactivity or learning difficulties and 2 cases of personality disorder
• ppts were matched by age and sex to control group of ppts (independent group design)
• mean age of NGRIs wa 31.7 years
• ppts with schizophrenia were matched with other people with same diagnosis but no history of murder
• all offenders were in custody and were kept medication free for two wees before brain scanning
• control group were also medication free
• all of ppts were injected with glucose tracer (fluourodeoxygucose), required to work at continuous performance task that was based around target recognition for 32 minutes, and then given a PET scan
• NGRIs were compared with controls on the level of activity (glucose metabolism) in right and left hemisphere of brain in 14 selected areas
• researchers looked at activity in six cortical areas (part of cerebral cortex which is the outermost layer of nerve tissues of the cerebral hemispheres) and eight subcortical area brain structure below the cortex

Question 5

what are the results of the study?

Answer 5

• compared to controls, NGRIs were found to have less activity in their prefrontal and parietal areas, more activity in their occipital areas, and no difference in their temporal areas
• raine et al argue that difference in activity in amygdala can be seen to support theories of violence that suggests it is due to unusual emotional responses such as lack of fear
• differences in corpus callosum activity between NGRIs and controls and suggest this can be matched up t evidence of people with severed corpus callosum which show they can have inappropriate emotional expression and inability to grasp long-term implications of situation

Question 6

what are the key findings of the study?

Answer 6

• the key findings support the hypothesis: brain function in NGRI group was in areas previously implicated in violent behaviour
• NGRIs had less activity in their **prefrontal brain regions*
• NGRIs has less activity in their parietal brain regions
• NGRIs had imbalance of activity between two hemispheres in amygdala, hippocampus, and thalamus - less activity in left side and more activity in right side of amygdala and hippocampus, more activity in right side of thalamus, though no difference in left side
• NGRIs had less activity in corpus callosum

Question 7

possible role of brain region: NGRIs had less activity in prefrontal brain regions

Answer 7

• difference in activity in prefrontal cortex can be linked to research which found that damage to this region can result in aggressive acts through impulsive behaviour, loss of self-control, altered emotional reactions, and inability to change behaviour

Question 8

possible role of brain region: NGRIs had less activity in parietal brain regions

Answer 8

• difference in activity in parietal regions may be linked with deficits in learning deficits, e.g. low verbal ability, and could contribute to problem with processing social and cognitive information
• this could ultimately predispose individual to educational and difficulties in employment which could predispose someone to rime and violent behaviour