Describe brain injury as an explanation of crime and anti-social behaviour (5 marks).
Brain injuries from sports, a fall, car crash, or alcohol abuse cause trauma to the brain and can cause
criminality (1). Alcohol abuse can cause brain damage and criminality by reducing thiamine absorption
and it also makes accidents more likely (1). Adults in prison with traumatic brain injury enter prison
younger than those without brain injury and reported higher rates of reoffending (1). The area of the brain
that is damaged determines what the exact change in behaviour is and therefore whether criminal and
anti-social behaviour occurs due to the injury (1). Damage to the amygdala, which controls and regulates
emotions, leads to an increase in impulsivity, aggression, and temperance, and potentially criminal
behaviour (1). Damage to the prefrontal cortex has also been associated with reduced awareness of
emotions, loss of memory and concentration, poor impulse control, and social judgement, which can all
contribute to criminal activity (1).
Describe the amygdala as an explanation of crime and anti-social behaviour (5 marks).
The normal function of the amygdala is to control and regulate emotion, therefore when it is not
functioning properly aggression and criminal behaviour are more likely (1). Poor functioning can be due
to innate factors such as inheritance, or environmental influences, such as trauma or brain injury (1).
Individuals with high aggression or psychopathic personality disorder have been shown to have a smaller
amygdala (1). Psychopathic individuals have reduced amygdala activity during moral decision-making.
This demonstrates psychopathic individuals would worry less about causing harm to others and therefore
more likely to be a criminal or anti-social (1). Animals that have their amygdala removed experimentally
become very placid, demonstrating the role of this structure in aggression and therefore criminality (1).
Conversely, electronically stimulating the amygdala experimentally creates “sham rage” in cats where
they become aggressive, again showing the link with aggression and criminality (1).
Describe XYY syndrome as an explanation of crime and anti-social behaviour (5 marks).
1 in 1000 males are born with an extra Y sex chromosome (XYY), so they have 47 chromosomes rather
than having 46 and the usual 2 sex chromosomes (XY) (1). This has been called “super male” syndrome
and can lead to the males being slightly taller than their siblings, and having a slightly lower intelligence
than their siblings (1). Many males do not realise they are XYY and are normal, in fact around 75% are
believed to be undiagnosed (1). However, the syndrome can also lead to the males being more impulsive,
and having behavioural problems which could lead to criminal behaviour (1). Some XYY males are also
more physically active. This can also lead to anti-social behaviour (1).
Describe personality as an explanation of crime and anti-social behaviour (5 marks).
Eysenck proposed his arousal theory which explains that the characteristics of psychoticism (P),
neuroticism (N), and extraversion (E) are linked with particular features of the central nervous system and
make criminal behaviour more likely (1). He said extraverts have an underactive ARAS system, thereby
needing more external stimulation, and potentially engaging in crime/ASB (1). He explained that
neurotics have an overactive sympathetic nervous system, with a lower threshold and higher activation
level making them more sensitive to stress (1). This makes neurotics more anxious, emotionally unstable
and more likely to react strongly to aversive stimuli, therefore being more aggressive and more likely to
engage in criminal activity (1). Finally, he explained that psychotics have higher levels of testosterone and
low MAO enzyme. This makes them aggressive, cold, egocentric, and lacking empathy, therefore also
making the potentially criminal (1).
