Hans Eysenck was one of the most controversial and prolific psychologists of the twentieth century. When he passed away in 1997, he was the most cited researcher in psychology. In this article we discuss his theory about the three dimensions of personality.
Eysenck has made a remarkable contribution to the field of psychology. He published 80 books and wrote hundreds of articles. He was also the founder and publisher of the influential magazine “Personality and Individual Differences.”
Hans Eysenck was born in Germany in 1916. His opposition to the Nazi Party forced him to flee, first to France and then to Britain. He received his PhD in psychology from the University of London in 1940.
During World War II, Hans Eysenck worked as a psychiatrist at the Mill Hill Emergency Hospital. Between 1945 and 1950 he was a psychologist at Maudsley Hospital. He later became director of the psychology department at the University of London’s Institute of Psychiatry. He held this position until 1983.
Hans Eysenck developed a personality theory that is very influential. It has so much influence because it covers very specific points. They are also easy to use in a daily speech. His personality theory is based on biological factors.
He argues that individuals inherit a type of nervous system that affects their ability to learn and adapt to the environment. However, Eysenck’s work was criticized for indicating that biological or genetic factors influence personality. These factors would determine an individual’s susceptibility to committing criminal behavior.
The PEN model of personality
Hans Eysenck used factor analysis to design his theory. In this way he identified three personality factors: psychoticism, extraversion and neuroticism (PEN). Each factor is a bipolar dimension. This means that every factor has an opposite. This leads to the three dimensions of personality:
- Extraversion vs Introversion
- Neuroticism vs Emotional Stability
- Psychoticism versus normality (added to the model in 1976)
Eysenck believed that biological factors influence a person’s score on these dimensions of personality. Those biological factors also include cortical arousal levels and hormonal levels, along with environmental factors such as learned behavior.
We should also mention that Eysenck really changed the term “psychoticism”. When one uses this term in his model, it refers to certain antisocial behaviors and not to mental illness.
Before developing the PEN model, Eysenck attempted to measure personality in two dimensions: extroversion-introversion and neuroticism-emotional stability.
The three dimensions of personality
Extraversion vs Introversion
People with high extroversion scores are more likely to participate in social activities. They are also often more communicative and feel more at ease in a group. In general, extroverts enjoy being the center of attention.
They often also build a larger social network of friends and companions. Extraversion is measured on a continuum that goes from high (extroverted) to low (introverted).
On the other hand, introverted people are often calmer. They shun large social gatherings. They can also often feel uncomfortable when they have to interact with strangers. In contrast, they have smaller groups of close friends. They are more likely to enjoy reflective activities.
Swiss psychoanalyst Carl Jung argued that the level of the extraversion-introversion dimension depended on the focus of an individual’s psychic energy. Jung believed that in extroverted people this energy was directed outward, towards other people.
The result was more social interactions. On the contrary, the psychic energy of introverted people is projected inwards. This causes them to participate in activities that are less social (Jung, 1921).
However, Eysenck believed that extraversion had to do with the levels of brain activity or cortical arousal. Extroverts experience lower levels of cortical arousal. This causes them to seek arousal from external stimuli. The higher activation in introverts causes them to avoid stimuli that can lead to a great arousal.
According to Yerkes and Dodson’s law, levels of arousal can affect an individual’s ability to perform. The theory states that arousal and performance form a bell-shaped curve. Performance declines during periods of high or low arousal (Yerkes and Dodson, 1908).
Neuroticism vs Emotional Stability
In his theory of the dimensions of personality, Hans Eysenck also posited a second dimension: emotional stability or neuroticism.
People with a high score for neuroticism often experience more stress and anxiety. They worry about issues that are quite unimportant. They also exaggerate their opinions and feel unable to cope with stressors.
These people focus their attention on the negative aspects of a situation rather than the positive. This can cause a person to adopt a disproportionately negative view of things. They may also feel envy or jealousy of others because they feel they are in a better position.
According to Eysenck, perfectionism and dissatisfaction are the hallmarks of neuroticism. On the other hand, there are the people with a low score for neuroticism. Those individuals will usually experience greater emotional stability.
We are talking about people who largely feel more able to deal with stressful events. They also manage to set goals that suit their abilities. People with a low neuroticism score are also often more tolerant of the mistakes of others. They also keep their composure in demanding situations.
Psychoticism vs Normality
It was only later that Hans Eysenck added psychoticism to his theory of personality dimensions. This third personality dimension ranges from normalcy (a low score for psychoticism) to a high level of psychoticism.
People with a higher level of psychoticism are more likely to exhibit irresponsible and ill-calculated behavior. These people may also break socially accepted rules. Their motivation is often a need for immediate gratification, regardless of the consequences.
However, psychoticism also has more positive connections. In a 1993 study, Eysenck compared participation scores on the Barron-Welsh Art Scale with scores on the Eysenck Personality Questionnaire. He found that people with high psychoticism scores tended to have more developed creative skills.
Eysenck concluded that psychoticism was influenced by biological factors and linked to the level 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 would be more difficult to adapt to social norms that we usually learn through reward and punishment.
This is the result of this reasoning. The theory holds that people may be more prone to criminal behavior if they try to satisfy their own interests. At the same time, they also violate the rules of conduct that others have accepted.
Eysenck made a connection between personality traits such as psychoticism and criminal tendencies. He also emphasized the genetic factors that influence these traits. This has led to criticism of his theory. The criticism was that Eysenck’s theory had adopted a deterministic view of behavior.
Criticism of Hans Eysenck’s theory
Researchers can use the study of twins to find out if personality is genetic. However, the findings are contradictory and inconclusive. Shields (1976) found that identical (identical) twins were significantly more similar in the introverted-extroverted and psychotic dimensions than fraternal (non-identical) twins.
Loehlin, Willerman, and Horn (1988) found that only 50% of the variations in personality dimension scores were due to heredity. This indicates that social factors are also important.
Eysenck’s theory contains one convincing element. He considers both nature and upbringing as determining factors. According to Eysenck, biological predisposition to certain personality traits, in combination with conditioning and socialization during childhood, determine the dimensions of the personality.
This approach is based on interaction. It thus contains a greater validity than a purely biological theory or environmental theory. It is also very much connected to the vulnerability-stress model. This model supports the idea of a biological predisposition that, in combination with an environmental stimulus, leads to a specific behavior.