3.3 raine Flashcards
What is the aim of Raine’s study?
to identifty brain impairments in murders who pleaded NGRI in areas of the brain linked in previous research to violence
what is the sample used in raine’s study?
- 82 pps - 41 ngri’s and 41controls
- 39 men and 2 women
- ngris - 3 had history of drug abuse, 6 had schizophrenia, 2 with epilepsy, 23 had history of brain damage
- controls - people of the same age and sex with no history of crime or mental illness, except 6 with schizophrenia
what is the independent variable in raine’s study?
whether the participant is a murderer who pleaded NGRI or a non murderer in control group
what is the dependent variable in raine’s study?
relative glucose levels in specific areas of the brain
what type of experiment + experimental design did raine use?
natural/quasi experiment
matched pairs design
describe the procedure of raine’s study
- the participants were tested at the University of California.
- each was injected with the glucose tracer and then performed the Continuous Performance Task (CPT) for 32 minutes - this involved identifying targets on a screen.
- then the PET scan was carried out - took ten images (slices) through the brain at 10mm intervals
Raine used other experimental controls:
* the participants were allowed to practice the CPT ten minutes before the glucose tracer was injected to make sure they were all equally familiar with it.
* raine made sure none of the participants (NGRIs or Controls) was on medication; the NGRIs had been kept medication-free for 2 weeks before the PET scan.
describe the results of raine’s study
- NGRIs showed less activity in the prefrontal cortex which is associated with rational thinking, self-restraint and memory (-0.04)
- NGRIs had less activity in the corpus callosum (-1.12)
- NGRIs had less activity on the left and more on the right in the amygdala (+0.05)
describe the conclusions of raine’s study
- hypothesis supported - murderers pleading NGRI have had different brain activity from controls, with impaired functioning in areas of the brain previously linked to being involved with violent behaviour
- …
evaluate the internal validity of raine’s study (strength)
P: A strength is the procedure has high internal validity because of control of extraneous variables by…
E: Ensuring all pps were medication free for 2 weeks prior to the PET scan.
T: This is a strength because Raine can be confident that differences in brain activity between NGRI’s and the control group were not affected by medication, thus are accurate.
evaluate the application of raine’s study (strength)
P: A strength of Raine’s results is they have application to society.
E: A difference of -0.04 in the prefrontal cortex was found between the NGRI’s and controls and was correlated with a lack of self-control and inability to learn from consequences.
T: Therefore according to these findings, monitoring ‘at risk’ individuals with deficits in these areas could reduce aggressive behaviour.
evaluate the reliability of raine’s study (strength)
P: A strength is reliability because the procedure was highly controlled and
standardised.
E: All pps practiced the same CPT for 10 mins (involved focussing on
blurred numbers to activate relevant areas of the brain), they were then
injected with a radioactive tracer (FDG), 32mins later they had a PET scan.
T: Therefore the procedure is replicable due to this standardisation meaning
reliability can be checked.
evaluate the internal validity of raine’s study (weakness)
P: Internal validity is lowered because cause and effect can’t be determined.
E: It is impossible to be sure that the brain activity measured in the NGRI’s caused the aggressive behaviour they were accused of. Extraneous variables such as upbringing may have contributed too or the deficit may have occurred after the event (during arrest).
T: Thus an accurate cause and effect conclusion can’t be drawn which limits
the internal validity.
evaluate the ecological validity of raine’s study (weakness)
P: Ecological validity is a weakness because of the artificial nature of the CPT and how brain activity was
Pmeasured
E: Being in a PET scanner is not a natural environment, resulting in unusual brain activity and focussing on blurred numbers is not the same as experiencing an aggressive situation in real life.
T: This is a weakness because the data gathered may not accurately
measure brain activity related to aggression.
evaluate the generalisability of raine’s study (weakness)
P: A weakness is that despite using a large sample it could be argued to have limited generalisability.
E: The 41 NGRIs claimed they lacked the capacity to remember the crimes they were on trial for, 3 suffered from substance abuse, 6 had SZ and 23 had head injuries.
T: Thus this sample doesn’t represent all aggressive or violent individuals due to these individual differences.
raine - social control - issues and debates
- Biological Psychology could be argued to control an individual’s behaviour to benefit society.
- An example of this would involve Raine’s study into the brains of criminals and non-criminals, when he found that NGRIs had lower activity in the Prefrontal Cortex (down 0.04 from controls) and higher in the amygdala (up 0.05 from controls).
- Following these results, PET scans could be used in society to find people with similar brain activity to NGRIs and give them a form of anger management before they have any violent episodes and kill someone.
- However, This control could hold negative implications.
- Raine’s scan found consistent results as NGRIs all had a similar level of brain activity but the results must be considered with caution because it was a correlation so cause and effect conclusions can’t be drawn.
- Therefore if the results were used to control behaviour, there is a chance non-violent people could have similar brain activity to NGRIs but end up being labelled as a potential killer before they had done anything to do so which would also give them a stigma, possibly making life harder for them for not much gain for the rest of society.
