raine et al

Question 1

aims

Answer 1

• look at direct measures of both cortical and subcortical brain functioning by using pet scans in people charged with murder who had pleaded by not guilty by reason of insanity (NGRI)
• hypothesized brain scans would show dysfunctions in areas of the brain linked to violence

Question 2

which areas of the brain are linked to violence

Answer 2

• prefrontal cortex
• amygdala
• corpus callosum
• thalamus
• hippocampus

Question 3

prefrontal cortex

Answer 3

implicated in planning decision making and moderating social behavior

Question 4

prefrontal cortex

Answer 4

implicated in planning decision making and moderating soca behavior

Question 5

amygdala

Answer 5

central role in how humans assess and respond to environmental threats and challenges - important for response and memory of emotions

Question 6

corpus callosum

Answer 6

• nerve cells physically connecting 2 hemispheres allowing for communication
• critical for contralateral control of body

Question 7

thalamus

Answer 7

filters information
received information from sense and passes it onto appropriate areas of the cerebral cortex

Question 8

hippocampus

Answer 8

regulates emotions and is associated with memory, especially long term memory

Question 9

sample - criminal group

Answer 9

• 41
• 39 male
• 2 female
• all committed manslaughter or murder
• all had been referred for brain scanning to find evidence that they were ngri for =
• schizophrenia (6)
• head injury/brain damage (23)
  -epilepsy

Question 10

non criminal control group

Answer 10

• 41, matched to age and gender to criminal group
• schizophrenic criminals were marched to schizophrenic non criminals
• rest of the control group were screened and showed no history of psychiatric illness

Question 11

controls before testing

Answer 11

• all offenders were in custody and kept medication free before scanning
• control group kept medication free
• tests were undertaken to make sure being left/right handed had no effect on behavior
• 14 murderers were non white and when compared to white murderers there were no differences on brain scans
• 23 murderers had head injuries which don’t show any different from non head injured murdered except for corpus callosum

Question 12

procedure

Answer 12

• participants were injected with a radioactive glucose tracer which would show the level of activity in different brain regions
• participants did a continuous performance task (CPT) which tested their pre frontal cortex
• CPT lasted 32 mins
• after ctp participants went to pet scanning room and their brain was scanned

Question 13

what was the cpt

Answer 13

-involved participants indicating every time the number 0 appeared in the screen

• the numbers visually degraded over time to require more effort of each participants pre frontal cortex

Question 14

what happened 10 minutes before participants were injected

Answer 14

they were given practice time of the ctp so they knew what to expect

Question 15

what happened 30 seconds before the cpt task

Answer 15

• they stated the actual task to ensure the novelty of the task didn’t show up on the scan

Question 16

what happened in the brain scanning room

Answer 16

participants brains were scanned 10 times at 10mm intervals to measure brain activities in cortical and subcortical areas

Question 17

results

Answer 17

compared to controls ngris showed:
- less activity in pre frontal cortex
- less activity in corpus callosum
- less activity in left side of amygdala
- more activity in right side of amygdala
- more activity in occipital areas
- more activity in right side of thalamus

Question 18

occipital areas

Answer 18

visual centeres of brain

Question 19

conclusions

Answer 19

• reduced brain activity in pre frontal cortex could explain impulse behavior and lack of self control
• differences in amygdala could support theory that violence is due to unusual emotional responses and lack of fear
• differences in corpus callosum corresponds to findings from split brain patients who show inappropriate emotional expression and inability in long term planning

Question 20

generalizability strengths

Answer 20

• large sample size of 82 so anomalies, e.g participants with unusual brain structures / people who disrupted test by not focusing on cpt dont skew results = more representative of wider population

Question 21

generalizability weaknesses

Answer 21

• ngris aren’t usual offenders so aren’t representative of other criminals so findings can’t be applied to all of them
• only 2 women in both groups limiting generalizability to female offenders

Question 22

reliability strengths

Answer 22

• pet scans are reliable brain imaging techniques giving objective and replicable results
• same cpt was used for all participants for same length of time, this identical procedure ensured all participants concentrated on the same thing and that similar brain activity was used for all participants
  = easy to repeat and check for consistency

Question 23

application strengths

Answer 23

-can be used to help prevent crimes by intervening in children who could be potential offenders due to genetic influence

• putting health and nutrition programs for pregnant women to help reduce biological risk factors for criminal behaviors, e.g not smoking

Question 24

application weaknesses

Answer 24

• can’t be applied to people who commit other violent crimes
• can’t be applied to other non violent criminals

Question 25

validity strengths

Answer 25

- participants were matched on age sex and ethnicity so results can be compared more accurately, increasing internal validity - use of scientific measures like pet scans and a standardized procedure

Question 26

validity weaknesses

Answer 26

can’t show cause and effect as it is uncertain when murderers develop brain defects

Question 27

ethics

Answer 27

- pet scans are harmful as participants have to be injectednwith a radioactive tracer