BIOLOGICAL PSYCHOLOGY
The central question is
Can we link biological
processes or structures
directly to human behaviour?
BIOLOGICAL PSYCHOLOGY
• Research suggests that brain dysfunction may
PREDISPOSE a person to being violent
• The FRONTAL brain region may be associated
with violent behaviour
• Some violent offenders plead NGRI (not guilty
by reason of insanity) to murder charges
BIOLOGICAL PSYCHOLOGY
• Discussion points
• What are the advantages to the Biological explanation of
behaviour?
• What are the disadvantages?
• Task: Read about your classic study Raine,1997 in your
E-textbook and your old textbook (page 134). Go
through slides 1-34 of this powerpoint. Make detailed
notes on this study. Take the quiz
http://www.holah.karoo.net/raine.htm to check your
understanding. Be ready next lesson to show me your
notes!!
BIOLOGICAL PSYCHOLOGY
RAINE
• The Raine hypothesis is that some seriously
violent individuals have localised brain damage in
certain areas of the brain including
the prefrontal cortex; the amygdala;
the thalamus; the hippocampus; and the corpus
callosum.
Top tip: take time to get to know the ‘brain’ see I
Learn for brain tutorials!
BRAIN ABNORMALITIES IN
MURDERERS INDICATED
BY POSITRON EMISSION
TOMOGRAPHY.
ADRIAN RAINE, MONTE BUCHSBAUM, AND
LORI LACASSE
(1997)
Typical Criminals?
THE FRONTAL LOBE
is important for
voluntary and
planned motor
behaviours - such
things as voluntary
movement of the
eyes, trunk, limbs
and the many
muscles used for
speech
Raine suggests three reasons why prefrontal
deficits may cause antisocial personality:
1. The region appears to be critical for self-restraint and
deliberate foresight. "One thing we know about antisocials is that they do not think ahead"
2. It’s crucial for learning conditioned responses e.g. a child
learns to link the thought of a misdeed with anxiety over
punishment. "Unconscious mental-emotional associations
such as these lie at the core of what we call conscience"
3. Prefrontal deficits are associated with low levels of
autonomic arousal. eople with Antisocial personality Disorder
(APD) may unconsciously be trying to compensate by seeking
stimulation
"For some kids one way of getting an arousal-buzz is by
robbing stores or beating people up”
CORPUS CALLOSUM
 Is the enormous bundle of fibres which
interconnects the left and right cerebral
hemispheres.
 It disseminates information from the
cerebral cortex on one side of the brain to
the same region on the other side – it is a
communication bridge .
TEMPORAL LOBE (TEMP' OR UL)
Various parts of it are important
for the sense of hearing, for
certain aspects of memory, and
for emotional/affective behaviour.
RAINE (1997) THE STUDY
• The participants:
• 41 murderers (39 males 2 females)
• Charged with murder/manslaughter in
California/USA
• All pled NGRI
• All were referred for physiological and
psychological examination
RAINE (1997) THE STUDY
• The ‘histories’
• head injury/brain damage(23)
• drug abuse (3)
• affective disorder (2)
• epilepsy (2)
• hyperactivity & learning impairment (3)
• personality disorder (2)
• Schizophrenia (6)
RAINE (1997) THE STUDY
• CONTROL GROUP
• 41 normal individuals (non murderers)
• matched for sex and age
• including 6 ‘murdering’ schizophrenics
who were matched with 6 ‘ non
murdering’ schizophrenics
• IQ, ethnicity, brain injury not matched!
RAINE (1997) THE STUDY
• The method
• A ‘natural’ experiment (quasi)
using independent measures
design where participants were
matched on key criteria.
• The procedure
• PET Scans were used to examine
the brain
RAINE (1997) THE STUDY
What does ‘PET’ as in PET scan
mean?
Positron Emission Tomography
How does it work?
This method assesses the amount of metabolic activity
in various parts of the brain
A scanning machine detects positrons which are
emitted. High amounts are associated with a higher
level of metabolic activity.
RAINE ET AL (1997) BRAIN ABNORMALITIES IN
MURDERERS
PET scans showing ‘hot spots’ for cognitive activities
RAINE ET AL (1997) BRAIN ABNORMALITIES IN
MURDERERS
PET scan of a subject
whilst practicing a new
language skill
A scan of the same
subject demonstrating
this skill after it had
become familiar
PHYSIOLOGICAL PSYCHOLOGY RAINE
• THE PET SCAN process
• Patients are injected with fluorodeoxyglucose
tracer (radioactive glucose)
• For about 30 minutes before the PET SCAN
the participants are engaged in a ‘continuous
activity’ task
• This activity aimed to activate the FRONTAL
LOBES, and the RIGHT TEMPORAL and
PARIETAL LOBES
"Continuous Performance Task:
Single digits (0-9) were presented for 40 ms at a rate of
one every 2 seconds. Subjects were told to press a
button using their right hand each time that they
detected the digit 0 and that it was equally important to
respond to zeros and not respond to non-zeros. Targets
were presented irregularly with a probability of
occurrence of 0.25. Stimuli were presented silently by
rear projection on a 24 x 24 cm screen, with a Kodak
carousel slide projector fitted with an Ilex No. 4 SynchroElectronic Shutter and blurred to a degree that makes
digits barely recognizable (such that a 2.8 diopter
correction is required to refocus clearly). The subject’s
eyes were 1.2m from the rear projection screen.”
FINDINGS
• Both groups performed similarly on
performance task
• There were certain characteristics
that were NOT CONTROLLED..i.e
• 6 murderers were left handed
• 14 murderers were non white
• 23 murderers had history of head injury
RAINE FOUND SOME
SIGNIFICANT RESULTS
• He suggested there was evidence
for DIFFERENCES in the brains of
the murderers
• He found amongst other things
LOWER ACTIVITY in some
CORTICAL REGIONS of the brain
ACTIVITY DEFICIT Raine's PET scans show
greater activity (red regions) in the prefrontal
cortex of a normal brain than in a murderer's
brain.
NORMAL
MURDERER
Diagrams from Raine’s research
SUMMARY OF DIFFERENCES IN THE
BRAINS OF THE MURDERERS
Reduced activity in
prefrontal cortex & corpus
callosum
The Left hemisphere
showed less activity than
the right
Abnormal asymmetries in
the amygdala
PHYSIOLOGICAL PSYCHOLOGY RAINE
Pre Frontal deficit - associated with
impulsivity
Amygdala - associated with
aggressive behaviour
Amygdala - reduced activity
associated with fearlessness
Corpus Callosum - dysfunction
associated with predisposition to
violence
CONCLUSION
It is unlikely that violence is due to
a single brain mechanism
There is evidence that - murderers
pleading NGRI may have different
brain functions to ‘normal’ people
There is some evidence that murderers have different brain
functions to psychiatric patients
WHAT these findings DO
demonstrate
That there MAY BE a link
between brain activity and a
predisposition towards violence
which should be investigated
further
WHAT THESE FINDINGS DO NOT
DEMONSTRATE
• That violent behaviour is ‘caused’ by
brain pathology
• That murderers are NOT
RESPONSIBLE for their actions
• That brain dysfunction causes violent
behaviour
EVALUATION ISSUES
Is the research Valid?
Areas of brain selected based on
previous research
but
Could IQ differences be a factor?
Is the research Reliable?
Could the same technique be used on
other people?
ETHICS
How might you criticise this study from an ethical point of
view?
Raine’s findings raise important ethical questions about
culpability and free will.
"To what extent, should we take disordered brain
functioning into account as part of the reason for certain
types of crime?
“Assuming these people are not responsible for their own
brain damage, should we hold them fully responsible for
their criminal acts?"
GENERALISATION
Can the findings of this study
be generalised to all
murderers?
Why or why not?
Application - how is this study
useful?
INTERVENTIONS
• Raine suggested a number of interventions that
could be applied.
• Cognitive and behavioural therapy and drug
therapy.
• Biofeedback – training children or adults to
control their own arousal levels.
• Children could be channelled into safe activities
that might satisfy their natural stimulation-seeking
and aggressive proclivities.
QUESTIONS
• Describe the strengths & weaknesses of the
NATURAL (Quasi) experimental method.
• What do you think might be the main difficulty in
drawing conclusions from PET observed ‘brain
activity’?
Identify one thing that cannot be concluded from
this study