Eysenck’s Personality Theory

• Eysenck proposed a theory of personality based on biological factors, arguing that individuals inherit a type of nervous system that affects their ability to learn and adapt to the environment. He compiled a battery of questions about behaviour, which he later applied to 700 soldiers who were being treated for neurotic disorders at the hospital.
• Extrovert

  • outgoing
  • excitable
  • sociable
  • excitement-seeking
  • aggressive
  • unreliable
• Introvert

  • inward-looking
  • reserved
  • quiet
  • serious
  • thoughtful
  • pessimistic
• Neuroticism

  • anxious
  • moody
  • depressed
  • over-reacts
• Psychoticism

  • cruel
  • insensitive
  • aggressive
  • lacking empathy
  • more likely to engage in criminality

  High psychoticism can overlap with serious mental disorders.
• Extroverts can be sociable and crave excitement and change, and thus can become bored easily. They tend to be carefree and optimistic. This can lead to impulsive rule breaking behaviour and they’re more likely to take risks and be thrill seekers.
• Introverts quiet and reserved; they are already over-aroused and shun sensation and stimulation. Introverts are reserved and plan their actions and control their emotions. They tend to be serious, reliable and pessimistic.
• A person's level of neuroticism is determined by the reactivity of their sympathetic nervous system. A stable person's nervous system will generally be less reactive to stressful situations, remaining calm and level headed.

  Someone high in neuroticism on the other hand will be much more unstable, and prone to overreacting to stimuli and may be quick to worry, anger or fear.
• People with high neuroticism are overly emotional and find it difficult to calm down once upset. Neurotic individuals have an ANS that responds quickly to stress but they are also harder to condition into following society's rules because their high anxiety levels prevent them from learning from punishment for their mistakes.
• Psychoticism has been related to high levels of testosterone. The higher the testosterone, the higher the level of psychoticism, with low levels related to more normal balanced behaviour.
• Eysenck argues that different personalities commit different levels of crime. He developed a personality test with personalities, such as choleric, sanguine, melancholic, and phlegmatic. Each is based on how much they ranked on the introvert, extrovert, neuroticism and psychoticism, level. People with high psychoticism were more likely to develop serious mental or psychiatric illnesses. Introverts were more likely to be criminal. Extroverts were more likely to get caught. Neuroticism also links to psychoticism and to criminality.