Presentation on the study by Raine (1997) on brain abnormalities in murderers

1. Raine et al
Emma, Harriet, Thalia

2. Aim
 To investigate patterns of brain activity in murderers
compared to a matched sample of non-murderers using
PET scanning.

3. Procedure
 82 participants, 41 murderers, 41 non-murderers,
matched on sex, age and other similarities (6 had
schizophrenia).
 A PET (positron emission tomography) scan was done on
each of the participants. A radioactive substance (called
a tracer) was injected into each participant, this is
picked up by the PET scan and shows the blood flow and
collects in the organs and tissue. Each of the
participants was given a ‘continuous performance task’
(which increased brain activities) 32 minutes before the
PET scan.

4. Results
 There was no difference in task performance.
 There was a significant difference in the brain
metabolism of glucose between murderers and non-
murderers.
 Murderers had a lower glucose metabolism in the
prefrontal cortex than non-murderers.
 There were different levels of activity in the amygdale
and hippocampus of murderers and non-murderers.
 Murderers had less activity in their corpus callosum.

5. Turn to crime
 People with a lower glucose metabolism in certain areas
of their brain are more likely to turn to crime. The
areas of the brain which lack activity are associated
with a lack of fear, low self-control, increased
aggression, impulsive behaviour and problems
controlling emotion. These characteristics could lead to
committing crime.

6. Issues
 Generalisability high – uses a large, varied sample
including a control group to show the difference within
the brain of murderers and non-murderers and can
biologically show why certain people turn to crime. Low
– within each group there was only 2 women so the
sample is androcentric and therefore may only explain
why males turn to crime.
 Usefulness  the study shows that criminal’s brains
work in a different way to other people’s and that the
lack of activity in certain parts of their brains (the
limbic system) may be the cause of them turning to
criminal activity.

7. Debates
 Internal determinism  the study shows that criminal
behaviour is determined by our biological make up,
specifically the way in which our brain works. A lack of
activity in certain parts of the brain associated with
things such as self-control and aggression can lead to
criminal actions.
 Psychology as a science  Objective results are
collected in this study through the use of specialist
equipment (PET scan) and as it is a lab experiment
there was high control e.g. each participant had their
PET scan 32 minutes after their continuous performance
task. The study is falsifiable as criminality can also be
explained through the influence of upbringing and the
people around you.

8. Quiz Questions
1. What does PET stand for?
2. How many of the non-murderers suffered
schizophrenia?
3. Did murderers have a lower or higher glucose
metabolism?
4. How long was there between the continuous
performance task and the PET scan?
5. What is a tracer?

9. Answers
1. Positron emission tomography
2. 6
3. Lower
4. 32
5. A radioactive material which travels in the blood.