Hans Eysenck: Three Personality Dimensions

Hans Eysenck was one of the most controversial and productive psychologists of the 20th century. When he died in 1997, he was the most renowned researcher in psychology. Eysenck contributed greatly to this field, publishing around 80 books and writing hundreds of articles. He was also the founder of the influential magazine “Personality and Individual Differences”.

He was born in Germany in 1916, and his opposition to the Nazi party forced him to flee first to France and then to Britain. He completed a doctorate in psychology at the University of London in 1940. During World War II, Hans Eysenck worked at Mill Hill Emergency Hospital as a psychiatrist. Between 1945 and 1950, he was a psychologist at Maudsley Hospital. He later served as director of the Department of Psychology at the Institute of Psychiatry at the University of London. He held this position until 1983.

Hans Eysenck developed a very influential personality theory. It is so influential because it deals with very specific points that are easily linked to everyday discourse. His personality theory is based on biological factors, and claims that individuals inherit a type of nervous system that affects their ability to learn and adapt to the environment. However, Eysenck’s work generated criticism for suggesting that biological or genetic factors affect personality and the individual’s sensitivity to engaging in criminal behavior.

Hans Eysenck’s PEN model of personality

Hans Eysenck identified three personality factors: psychoticism, extraversion and neuroticism (PEN) using factor analysis to design his theory. Each of Eysenck’s factors is a bipolar dimension, which means that each has an opposite.

• Extraversion versus introversion
• Neuroticism towards emotional stability
• Psychoticism against normality (added to the model in 1976)

Eysenck believed that biological factors, including cortical excitation and hormonal levels, along with environmental factors such as learned behavior, affect a person’s score on these personality dimensions.

It should be emphasized that Eysenck really changed the concept of “psychoticism”. When used in the model, it refers to certain antisocial behaviors, not mental illness. Prior to the development of the PEN model, Eysenck attempted to measure personality in two dimensions: extraversion-introversion and neuroticism-emotional stability.

Extraversion introversion

People with a high degree of extraversion participate more in social activities. They tend to be more communicative and feel more comfortable in a group. In general, extroverts like to be the focal point and often gather a larger social network of friends and co-workers. Extraversion is measured on a continuum, ranging from high (extroverted) to low (introverted).

On the other hand, introverts tend to be calmer, avoid large social gatherings, and may feel uncomfortable when interacting with strangers. Instead, they retain smaller groups of close friends and are more likely to enjoy contemplative exercises.

The Swiss psychoanalyst  Carl Jung suggested that levels of extraversion-introversion depend on the focus on the individual’s psychic energy. In extroverts, he believed that this energy was directed towards the outside, towards other people, which resulted in more social interactions. However, the psychic energy of introverts is projected inward, causing them to engage in less social activities (Jung, 1921).

However, Eysenck believed that extraversion was related to levels of brain activity or cortical excitation. Extroverts experience lower levels of cortical excitation, which causes them to seek excitation from external stimuli. The higher activation levels in introverts mean that they avoid stimuli that can lead to great excitation.

On the other hand, according to Yerkes-Dodson law, voltage levels can affect an individual’s performance. The theory is that excitation and performance follow a bell-shaped curve, and the other decreases during periods of high or low excitation (Yerkes and Dodson, 1908).

Neuroticism-emotional stability

Hans Eysenck also suggested another dimension: emotional stability or neuroticism. People with high neuroticism scores tend to experience higher levels of stress and anxiety. They worry about relatively insignificant problems, exaggerate their opinion and feel unable to cope with stress.

A focus on the negative aspects of a situation instead of the positive aspects can cause a person to adopt a disproportionately negative perspective. They may feel jealous or jealous of others who, according to them, are in a better position.

Eysenck characterizes neuroticism with perfectionism and dissatisfaction. On the other hand, a person with a low neuroticism score will generally experience greater emotional stability. We are talking about people who for the most part feel better able to cope with stressful events and set goals that suit their abilities. People with low neuroticism scores tend to be more tolerant of others’ mistakes and remain calmer in demanding situations.

Psychoticism-normality

Psychoticism was a late addition to Hans Eysenck’s personality theory. It was included in 1976. This third personality dimension varies from normalcy (low psychotism) to high psychotism.

People with higher psychoticism are more likely to engage in irresponsible or poorly calculated behavior. These people may also be in conflict with accepted social norms and motivated by a need for immediate gratification, regardless of the consequences.

But psychoticism also has several positive associations. In a 1993 study, Eysenck compared the participation scores from the Barron-Welsh Art Scale and the Eysenck Personality Questionnaire and found that people with high psychoticism scores tended to have more advanced creative skills.

Eysenck suggested that psychoticism was influenced by biological factors and correlated with levels of hormones such as testosterone. According to the PEN model, high levels of psychoticism reduce a person’s ability to respond to conditioning. This means that it will be more difficult to adapt to the social norms that we usually learn through reward and punishment.

As a result, the theory suggests that people may be more prone to criminal behavior when trying to satisfy their own interests while violating the rules of conduct accepted by others. The association of personality traits, such as psychoticism, with criminal tendencies, together with Eysenck’s emphasis on genetics affecting these traits, has resulted in criticism of his theory for adopting a deterministic view of behavior.

Criticism of Hans Eysenck’s theory

Researchers can use twin studies to see if personality is genetic. However, the findings are contradictory and incomplete. Shields (1976) found that monozygotic (identical) twins were significantly more similar in introverted-extroverted and psychotic dimensions than dizygotic (non-identical) twins. Loehlin, Willerman and Horn (1988) found that only 50% of the variations in personality dimensions are due to hereditary traits. This suggests that social factors are also important.

A virtue of Eysenck’s theory is that it considers both nature and education as influencing factors. He argues that biological predispositions to certain personality traits, combined with conditioning and socialization in childhood, presuppose our personality.

This interactionist approach can therefore accumulate a greater validity than a purely biological or environmental theory. It is also very well related to the stress-vulnerability model, which argues for a biological predisposition that is combined with the environment as a trigger for a particular behavior.