Eysenck’s theory of criminal personality.

• Although this is a psychological theory, Eysenck did acknowledge that personalis traits have a biological basis.it is therefore sometimes seen as the half-waypoint between a biological explanation and a psychological explanation. Eysenck proposed that personality and behaviour can be represented along 2 dimensions. 
• The self-report tool measured 3 parts on the personally on a scale:

  Extraversion - introversion: measured the amount of sensations an individual sought. Biologically, extraversion is linked to arousal levels in the brain.

  Neuroticism - stability: measured the amount of emotional activity experienced in an individual. Biologically, neuroticism is linked to a sensitive limbic system. 

  Psychoticism: measured the morals, remorse and guilt experienced by an individual biologically, these traits are influenced by hormones such as testosterone
• Details of the criminal personality:

  Eysenck believes that the personality traits are biological in origin - they occur as a result of the type of nervous system that we inherit (67%).

  All personality types (Inc criminal personality type) have an innate, biological basis.

  Eysenck proposed that behaviour is measured along 2 dimensions. The 2 dimensions combine to form a variety or personality traits. He later added a 3rd dimension of psychoticism.

  Personality type is measured using the Eysenck personality inventory (EPI), with later the addition of psychoticism included.
• Role of socialisation:

  personality is linked to offending behaviour via socialisation process. He saw offending behaviour as developmentally immature: its selfish and concerned with immediate Gratification.
• Role of socialisation:

  Children are taught to become more able to delay gratification and more socially orientated through socialisation. Eysenck believed that people with high e and N scores had nervous systems that made them difficult to condition. They are less likely to learn anxiety response to antisocial impulses and consequently be more likely to act antisocially in situations where the opportunity presented itself.
• A strength of Eysenck's criminal personality is that there is supporting evidence. Eysenck and Eysenck compared over 2000 male prisoners EPI scores with over 2000 male controls. The prisoners scored highest for psychoticism, neuroticism and extraversion across the whole age range (16-69 years). This supports the theory because it is inline with what the theory would predict, higher it should be noted that later research has only found a link between psychoticism and offender behaviour, suggesting the theory may lack reliability.
• strength is it recognises the role of biology and psychology. theory recognises biology plays a role in criminality, personality may have a genetic basis. This theory fits well with the biological explanation of offender behaviour which is highly scientific. the theory overlaps with biological explanations of antisocial personality disorder (APD), offenders are cold, uncaring an incapable of empathy. suggests the theory accounts for both biological and psychological factors, giving more holistic view of offender behaviour which useful in understanding why offenders commit crime.
• weakness : been criticised for being too simplistic. More modern personality theories such as Digmans five factor model suggests that there are other personality dimensions that contribute to an individual. He also included openness, agreeableness and conscientiousness. This means that there are many different combinations that can link to criminal personality. This suggests that having a high E or N score does not mean offending is inevitable, as there are many other aspects to a persons personality, thus reducing the predictive validity of this explanation.
• A weakness of Eysenck’s criminal personality is that it suffers from cultural bias. Bartol studied Hispanic and African American offenders in a prison in New York. He studied 6 different groups, based on what crimes they’d committed and what their criminal history was. He found that in all of the groups, they all scored lower for extraversion than a control group (a group not in prison). This suggests that Eysenck’s theory may not he generalisable to cultures other than the ones he studied, which undermines the validity of the theory.