An integrative look at criminal behaviour

An integrative look at criminal
2.3 The biological level of analysis
Criminal behaviour
• Name programmes you know that are about
solving crime…
• And some of them that integrate medical and
psychological information into the episodes…
Category: Crime television series
CSI (Miami, NY…)
Wire in the Blood
Criminal Minds
Midsomer Murders
Detective Linley
Miss Marple
In this category: 597
The nature of crime
• We are both appalled and fascinated by the
nature of crime
• We also want to prevent and solve crime, right?
• So what makes people turn to criminal
behaviour? Born a criminal? Bad environment? In
this chapter we are going to investigate criminal
behaviour from the biological level of analysis
and come back to use the cognitive and
sociocultural when we have studied them.
What makes one turn to criminal
• Early theorists believed that there were “criminal
types” (and some still do!) that they came from
certain ethnic groups, had certain physical
characteristics (strong jawline, high cheekbone,
large ears, extra fingers or toes)
• Today, psychologists recognize that the origins of
criminal behaviour are complex, resulting of a
combination of risk factors – both biological and
environmental factors – which interact.
• The more of these factors – the more likely the
individual is to engage in criminal behaviour
The biological level of analysis
• Genetics
• Brain
• Neurotransmitters
• Hormones
Are some born to be criminals?
• No, however Biological factors can contribute
to criminality
• Twin studies
• Christiansen 1977 studied 3586 sets of twins
• Results indicate that there may be some
genetic factors: concordance rate: 35% in MZ
males, 13% DZ males
• 21 % MZ females, 8% DZ women
• Limitations: ?
• Share same environment
• MZ twins Get treated more similar than DZ
Adoption studies
• Hutchings and Mednick (1975)
• Results: found that if both the biological and
adoptive fathers had criminal records , 36,2 %
of sons had a criminal record
• If only the biological father had it, it dropped
to 21,4 %
• If only the adoptive father, it fell to 11,5%
• When none of the fathers had a record, 10,5%
of sons had one
Adoption studies
• This study shows the importance of
environmental factors in combination with
genetic factors
1. Similar homes
2. Some children are several years when they
are adopted
Limitations with genetic factors
1. What is a “crime gene” – and which crime
does it reflect…tax crime? Drugs? Murder?
2. Can’t explain why it change over time in a
person’s life – peak in their 20s and declining
after 30
The brain
• Blair et al (1999) examined brains of convicted
psychopaths using PET scans that revealed
impairment of the pathways between
amygdala and the frontal lobe.
• Amygdala –
responsible for emotional responses
• Frontal lobe - decision making
The Brain
• The theory is that due to this impairment,
they have a difficulty in moderating their
emotional reactions, which in turn has an
effect on social relationships which leads to
undeveloped empathy, undeveloped feeling of
guilt and that they act more impulsively
The brain
• The frontal brain hypothesis – the theory
behind that due to a malfunctioning
relationship between frontal cortex and the
limbic system (amygdala is part of the limbic
system) could cause criminal behaviour
• Does not explain all criminal behaviour
Raine et al (1997)
Read Raine et al (1997) study on brain
abnormalities in murderers indicated by positron
emission tomography (PET) and write a
summary of it.
Use max 200 words,
the aim, method and results.
Neurochemical imbalances
Neurotransmitters and hormones
• Seems to best explain the significant gender
difference with regard to crime
• 2004 US, 90,1 % arrested murderers were
male, 82,1% arrested for violent crime were
Neurochemical imbalances
Two explanations for this is:
• Low levels of serotonin (which men usually
have) is linked to antisocial and impulsive
• Violent criminals have higher doses of
testosterone than non-aggressive criminals
• Limitations: correlational studies = no cause
and effect
• Unsure if chemical imbalances are due to
genetic factors or environmental
Nature of crime
• Biological level of analysis can’t on its own
give the full explanation of the nature of
crime, to be continued…
• But what if…
• (TOK: ethics on p. 63)

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