Self-understanding

Hans Eyesenck
Eysenck's theory of personality focused on temperaments, which he believed were largely controlled by genetic influences. He utilized a statistical technique known as factor analysis to identify what he believed were the two primary dimensions of personality, extraversion, and neuroticism. He later added a third dimension known as psychoticism.
Once he had identified the three primary dimensions, Eysenck proceeded to construct a paper-and-pencil test to measure them. The most recent version of the test is the Eysenck Personality Questionnaire (EPQ). Extraverts are sociable and impulsive individuals who like excitement and who are oriented toward external reality; introverts are quiet, introspective individuals who are oriented toward inner reality and who prefer a well-ordered life. Although these definitions are similar to those used by Jung (see Chapter 3), Eysenck did not accept Jung’s account of the origins of these attitudes nor the manner in which they operate in the subterranean psyche of the individual.
A person’s level of neuroticism/stability 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. They are overly emotional and find it difficult to calm down once upset. Neurotic individuals have an ANS that responds quickly to stress.
Eysenck (1966) later added a third trait / dimension - Psychoticism – e.g., lacking in empathy, cruel, a loner, aggressive and troublesome. This 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 behavior.
Many psychotic individuals, especially those diagnosed with schizophrenia, also have concepts that are diffuse and are overinclsive(과포함적), in consequence, are able to connect ideas that others would see as unrelated. Eysenck cited considerable evidence that schizophrenics perform very well on tests of divergent thinking(창의적 사고), which shows their ability to think in unusual and original ways. For example, an item on such a test might be: “How many uses can you think of for a brick?” More normal people might reply that it can be used to build houses, to repair walkways, and to repair chimneys. People high on the psychoticism dimension, as well as schizophrenics, might give the same responses and quickly add the following: it could be used also as a doorstop, as a paperweight, as a thing to make water in a pond splash, as a weapon of aggression, as a walnut crusher, and as a substitute barbell to do bicep curls. Thus, people higher on psychoticism give more unusual responses, thereby showing greater originality and fluency of ideas. 정신분열병=schizophrenia
Eysenck claimed that the originality of both geniuses and psychotics is based on a cognitive style that is overinclusive—that allows them to interpret all kinds of ideas as relevant to any problem under consideration. He thought further that this overinclusiveness may be due to a failure of cognitive inhibition caused by an excess of dopamine and a lack of serotonin in the brain. Specifically, Eysenck maintained that normal people process incoming information by narrowing it down—by deciding which information is relevant to the solution of a problem and which information is irrelevant.
The most notable strength of trait theory is its clarity, which makes it easily understood. This ease of understanding makes trait theory easy to implement, facilitating its use in the development of several assessment devices for patients. Its major weakness is that it does not fully address why or how traits develop. Due to its statistical nature, trait theory offers no clarification of personality development.
Other strengths include:

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  Objectivity: Trait theory completely relies on statistical analysis or hard data. Unlike several other theories, the personal experience or subjectivity of the theorists is not considered in trait theory. Since the personal interpretation of subjective factors can lead to bias ideas; trait theory has no bias.
  

Other weaknesses include:

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  It cannot predict future behavior: Trait theory does not substantially account for personality changes, both temporarily and in the long term. Since it does not address trait development, it offers little or no guidance on how to change trait aspects. It does not address how positive traits can be highlighted or how negative traits can be ameliorated.
  

Unlike the other theories of personality like humanistic or psychoanalytic theories, the trait theory approach to personality focuses primarily on the differences between people. The interaction and combination of different traits leads to the formation of personality that is unique to each individual. Trait theory identifies and measures these personality characteristics.