classic: raine et al

when did Raine carry out his study?

1997

what was the aim of the study?

to see whether there was different brain functioning in a group of murderers compared to a control group

what did Raine predict about the study?

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

what previous research suggested Raine's prediction for the study?

violent offenders had poorer brain functioning, the prefrontal cortex and limbic structures link to aggression, dysfunctions in other brain areas are expected from violent offenders

what does the corpus collosum do?

connect both sides of the brain

what type of brain scan did Raine's study use?

PET scans

who were the participants?

41 murderers pleading not guilty for reasons of insanity (39 males, 2 females)

who were the 41 murderers compared to?

a control group of 41 participants

why were all NGRI participants referred to the imaging centre?

for legal reasons, such as to obtain evidence for the defence

how many of the NGRI referrals had schizophrenia?

6

how many of the NGRI referrals had head injuries or organic damage?

23

how many of the NGRI referrals struggled with drug abuse?

3

how many of the NGRI referrals had hyperactivity and learning difficulties?

3

how many of the NGRI referrals had a personality disorder?

2

what were participants matched to the control group based on?

age and sex

what groups design did the study use?

independent groups design

what was the mean age of the NGRI's?

31.7

who were NGRI participants with schizophrenia matched with?

other people with the same diagnosis but no history of murder

how long before the brain scan were participants kept medication free for?

2 weeks

what were all participants injected with for the PET scan?

fluorodeoxyglucose

what were participants required to work at before the PET scan?

a continuous performance task based around target recognition for 32 minutes

what was the continuous performance task participants were given before the PET scan?

they wore headphones and pressed a button every time a beeping tone was heard

why were participants given a continuous performance task before the PET scan?

to activate the prefrontal cortex and put participants in the same mental state

what were the NGRI participants compared with the control group on?

the level of activity in the right and left hemispheres of the brain in 14 selected areas

what were the 14 selected areas researchers looked at?

6 cortical areas (part of the cerebral cortex, the outermost layer of nerve tissues of the cerebral hemispheres), and 8 subcortical areas (brain structures below the cortex)

what do the key findings of Raine's study support?

the hypothesis that brain dysfunction in the NGRI group was in areas previously implicated in violent behaviour

what are the 4 areas the cerebral cortex is commonly described in terms of?

prefrontal, parietal, temporal, and occipital

what is suggested by the NGRI group having less activity in their prefrontal brain regions?

can be linked to research suggesting damage to this region can result in aggressive acts through impulsive behaviour, loss of self-control, immaturity, altered emotional reactions and inability to change behaviour

what is suggested by the NGRI group having less activity in their parietal brain regions?

linked with deficits in learning, such as low verbal ability and difficulty processing social and cognitive information, this could lead to difficulties in employment or education, resulting in crime and violent behaviour

what is suggested by the NGRI group having an imbalance of activity between the two hemispheres in the amygdala?

can support theories of violence that suggest it is due to unusual emotional responses such as a lack of fear

which hemisphere were the NGRI group shown to have less activity in the amygdala and hippocampus?

the left hemisphere

what was found about activity of the thalamus in each hemisphere in the NGRI group?

the left side showed no difference, but the right ride showed more activity

what is suggested by the NGRI group having less activity in the corpus collosum?

it can be matched to evidence of people with a severed corpus collosum, which show they can have inappropriate emotional expression and an inability to grasp long-term implications of a situation

what did Raine conclude?

violent behaviour could not be attributed to a single brain region and that multiple regions were involved as well as environmental factors

what is speculated about the differences in brain function?

it does not directly cause violent behaviour but predisposes those with dysfunction when combined with other social, psychological and environmental predispositions to violent behaviour

what did Raine note about his findings to prevent misinterpretations?

cannot be generalised to other violent offenders or types of crime, cannot show violence is only caused by behaviour, and does not say anything about NGRI's not being responsible or the causes of brain differences

what other factors have an increased risk of an individual having a biological predisposition to antisocial behaviour?

birth complications, poor parents, physical abuse, malnutrition or smoking/drinking during pregnancy