Evaluate the classic study of Raine et al (1997):
Aim: Raine et al wanted to use PET scanning technology to identify brain
impairment in people charged with murder who had pleaded not guilty for reasons of
insanity. (NGRI).
The researchers hypothesise that brain scans would show dysfunctions in areas
linked in previous research to violence eg. the prefrontal cortex and the amygdala.
Sample:
two groups - 41 murderers and 41 non murderers
The experimental group consisted of 39 men and 2 women charged with murder or
manslaughter in California, USA.
Generalisability:
The study considers a range of participants to ensure that the results were
generalisability. The study used a matched pairs design. They were matched on sex,
age and ethnicity with a control group of non murderers. The sample may be age
biased as the younger you are the less developed your prefrontal cortex is. This is
important when examining aggression as as you get older you have more impulse
control and therefore more control over your actions. The sample is also gender
biased. This is because it is androcentric or male dominated. There were 2 female
and 39 male participants. This is an issue as men can be seen as more aggressive
than females. This shows that the study can be seen as not generalisable as it is
both gender and age biased when it comes to the sample used, making it difficult to
generalise to a range of other people.
Procedure:
Each participant underwent a PET scan on their brain. They were injected with a
radioactive tracer to ‘light up’ brain metabolism on the scanner. It took 32 minutes
before participants started the tasks under the scanner. When in the scanner they
completed a continuous performance task. This involved identifying targets on the
screen and pressing a button. The scan took 10 images throughout the brain at 10
mm intervals.
Reliability:
Raine et al’s study has high internal reliability due to having a standardised
procedure. For example the same machine was used on all participants for a
standard 32 minutes and the PET scans followed the same well-established protocol
so that the experience of the procedure would have been identical for all participants.
Dustin Pardini et al carried out a study in 2014 in which he identified 56 males who
had been part of a study 20 years earlier when they were 6 or 7 years old. Over the
20 years these men had consistently behaved aggressively, including being involved