Linking Personality and Criminal behaviour

Hans Eysenck's Personality Theory:

Hans Eysenck (1964), developed a personality theory which he continued to develop all throughout his career. At first he identified two dimensions of the personality which are known as; extraversion and Neuroticism. He later linked his personality theory to criminal behaviour which is when he introduced the third dimension called psychoticism which he believed was genetically determined. Here is a diagram of his theory:

When evaluating Eysenck's theory Howitt (2009) points out how this test helps identify that rapists and child abusers are extravert, neurotic and psychotic however it doesn't identify why they carry out these criminal acts. On the other hand it must be highlighted that Han's theory can be used in helping prevent individuals from developing into offenders as if someone scores high on P, E and N they are more likely to be a criminal and therefore practices can be put in place to help prevent this such as parenting interventions and early treatment. 

As well as biological factors there is also environmental factors that should be taking into account when discussing criminal behaviour. John Bowlby (1944) studied the effects on children when they were separated from their mothers. He took 44 children that were described as 'thieves' between the ages of 5 and 17 years and a further 44 children as a control group. Bowlby found that out of the 14 'affectionless' thieves 12 of them had early experiences of frequent separations from their mothers. Therefore it can be concluded that the children may not have became offenders if they had not suffered harmful experiences during development. Moreover Bowlbys's study helps identify how environmental factors can play a key role in the developmental of offenders. If a person has both personality traits and are in an environment that triggers offending behaviour such as being separated from their mother then this person is more than likely to become a criminal as they have suffered from both genetic and environmental factors.  

For further reading on this fascinating subject:
Psychology Review
http://www.simplypsychology.org/personality-theories.html
Psychology The Science of Mind and Behaviour by Richard Gross
Oxford Handbook of Criminology by Reiner and Martin

Linking Brain Injuries and Criminals

It has been suggested that there is a link between certain brain activity and anti-social behaviour (Robert Hare, 1986 as cited in Muir, 2015). Hare is famous for work with psychopaths and sociopaths finding a link between psychopaths and risk taking behaviour.

Damage to the limbic system and the temporal lobe have been identified as resulting in criminal behaviour. The limbic system controls our memory, emotions, and parental and social instincts. Furthermore, the temporal lobe is one of the easiest parts of the brain to damage through knocks to the head, car accidents and internal, resulting in violent behaviour. Studies such as Lewis et al (1986) support this information by finding that all fifteen of the participants suffered head injuries prior to prison.

However the effects of a brain injury can vary from individual to individual with minor injuries resulting in the person possibly suffering from concussion, dizziness and headaches. More severe brain injuries may cause a person to suffer from dramatic mood, personality changes, loss of executive functioning and poor judgement.

Many serial killers have suffered a head trauma or injury during childhood or at birth such as Leonard Lake, Ted Bundy, Bobby Joe Long and Fred West. In particular Fred west suffered injuries to his frontal lobe during a road accident which is thought to be the cause of his sexual appetite and violent behaviour.

More locally 21, 217 people in Scotland suffered a head injury in 2013/14, suggesting that someone has trauma to the head every ninety minutes. The Acquired brain injury service in the Angus area helps people physically, cognitively and emotionally after a brain injury.

For more in-depth information please read the following;
Muir, F., 2015. Brain Injuries. [lecture notes]. Dundee and Angus College, Criminology, 09 December 2015.
Peat, R., 2007. Acquired brain injury. unpublished.