biological explanations of offending behaviour for the forensic psychology topic of AQA psychology a level

3. Atavistic form
 Definition: a biological approach to offending that attributes criminal activity to the fact that offenders are ‘genetic
throwbacks’ or primitive sub-species ill-suited to conforming to the rules of modern society. Such individuals are
distinguishable by particular facial and cranial features (the skull).
Lombroso’s research
 Essentially the idea a criminal can be identified by
the way they look.
 Lombroso suggested this as an explanation of
offending behaviour, theorising that criminals were
biologically different from non-criminals.
 Lombroso meticulously examined the facial and
cranial features of hundreds of Italian convicts
(both living and dead) and proposed that the
atavistic form was associated with a number of
physical anomalies which were key indicators of
criminality
Lombroso

4. Atavistic characteristics
Cranial characteristics:
• Narrow, sloping brow
• Strong prominent jaw
• High cheekbones
• Facial asymmetry
Physical features:
• Dark skin
• Extra toes
• Extra nipples
• Extra fingers
Specific traits:
• Murderers – bloodshot eyes, curly hair, long ears
• Sexual deviants – glinting eyes, swollen fleshy lips,
projecting ears
• Fraudsters – thin and reedy lips
Other characteristics:
• Insensitivity to pain
• Use of criminal slang
• Tattoos
• Unemployment
Lombroso examined the skulls of 283 dead criminals and 3839 living criminals and
concluded that 40% of criminal acts could be accounted for by atavistic characters.
Offenders were seen by Lombroso as lacking evolutionary development, and their
savage and untamed nature meant they would find it impossible to adjust to the
demands of civilised society and would inevitably turn to crime.
Lombroso saw criminal behaviour as a natural tendency rooted in the genealogy of
those who engage in it.

6. Genetic and neural explanations

7. Genetic explanation
Twin studies Candidate genes Diathesis-stress model

8. GENETIC EXPLANATION
Genetic explanations for crime suggest that offenders inherit a gene, or a combination of genes, that predispose them to commit a
crime. The importance of genes is illustrated in twin studies – the first criminal twin study was conducted by Johannes Lange in 1930
Lange investigated 13 identical (MZ) and 17 non
identical (DZ) twins where one twin in each pair had
served time in prison.
Lange found that 10 of the MZ twins but only 2 of
the DZ twins had a twin who was also in prison and
concluded that genetic factors must play a
predominant part in offending behaviour.
1st twin in
prison
2nd twin in
prison
Percent match
Monozygotic
twins
13 10 77%
Dizygotic
twins
17 2 12%
Candidate genes
A genetic analysis of almost 900 offenders by
Tiihonen et al revealed abnormalities on two
genes that may be associated with violent crime –
the MAOA gene which is linked to aggressive
behaviour and controls dopamine and serotonin,
and the CDH13 gene, which is linked to substance
abuse and attention deficit disorder. Tiihonen
found individuals with a high risk combination
were 13 times more likely to have a history of
violent behaviour – however, this research is in its
infancy and has not yet been replicated.
DIATHESIS-STRESS MODEL: if genetics do have some effect on
offending, it seems that this is likely to be at least partly
moderated by the effects of the environment. A tendency to
criminal behaviour may come about through a combination of
genetic predisposition and biological or psychological triggers –
for example being raised in a dysfunctional environment or
having criminal role models

9. Neural explanations
Evidence suggests there may be a neural difference in the brains of criminals and non-criminals. Much of this area
has been investigated using individuals diagnosed with antisocial personality disorder, which is associated with
reduced emotional responses, and a lack of empathy for the feelings of others, and is a condition that characterises
many convicted criminals.
Prefrontal cortex – Raine has
conducted many studies of the APD
brain, reporting that there are
several dozen brain imaging
studies which demonstrate
reduced activity in the prefrontal
cortex in those with APD, and this I
the part of the brain which
regulates emotional behaviour.
Alongside this, Raine found an
11% reduction in the volume of
grey matter in the prefrontal
cortex of people with APD
compared to controls.
Mirror neurons – recent research
suggests that criminal with APD can
experience empathy, but do so more
sporadically than those without.
Keysers et al found that only when
criminals were asked to emphasise
with a person on film experiencing pain
did their empathy reaction (controlled
by mirror neurons) activate. This
suggested that those with APD can
empathise but may have a neural
‘switch’ which can be turned on or off,
unlike the ‘normal brain’ which is
permentantly on.