Eysenck's Theory of Personality

Eysenck's Personality Theory Explanation

Eysenck's theory of personality is a halfway house between biological and psychological theories of explanations of crime. Though his theory of criminal personality would be appropriately classified as psychological, he argues that all personality types have biological bases.

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These can include dysfunctional learning environments, the impact of the family, cognitive factors and personality. In addition, a person with a criminal personality cannot be conditioned easily, are cold and unfeeling, and is likely to engage in offending behaviour.

Fig. 1 - A criminal personality on Eysenck's scale includes high ratings in extraversion (E), neuroticism (N), and psychoticism (P).

Eysenck's Theory of Personality and Crime

In 1964, Eysenck proposed that personality can be divided into two core dimensions. These dimensions took the form of a scale and comprised introversion/extraversion (E) and stability/neuroticism (N).

Where a person landed on this scale determines their personality type. In other words, a person may skew more towards an introverted personality type on the scale between introversion and extraversion, and vice versa.

Extraversion

According to Eysenck, extraversion is partly to do with specific systems within the brain, more notably, the ascending reticular activating system (ARAS). This system is inherited, and those who are extraverted tend to have a less sensitive ARAS (the biological aspect of personality).

Extraverts seek more stimulation to reach higher levels of stimulation that satisfies them. The core aspect of this is impulsivity in extroverts. This lack of conditioning of their conscience and drive to seek highly stimulating situations may lead to criminal behaviours.

Introversion

According to Eysenck, introversion is due to a highly sensitive ARAS. An environment that is abundant in sensation and stimulation tends to be shunned by those who are introverted, quieter, and more reserved. As the ARAS is highly sensitive, it is easily aroused; thus, these environments tend to be overwhelming.

Neuroticism

Eysenck specifically believed neuroticism was related to the limbic system within the brain and how easily overwhelmed it is. Those with limbic systems overwhelmed by stressful situations tend to skew more towards the neurotic side on the scale of neuroticism.

When an emotionally stable person is confronted with a stressful situation, they can react more reasonably.

Those who skew more towards the neurotic side tend to act more unstable and react quickly to stress; they have a more emotional drive, resulting in more antisocial behaviours. When exposed to stimuli that can be deemed stressful, neurotic individuals respond emotionally by being more anxious than usual, being quick to worry, and displaying high levels of irritability.

Psychoticism

This trait has been related to high levels of testosterone. When testosterone levels are high, it is likely that levels of psychoticism will also be high.

A lack of empathy can result in antisocial behaviours, which leads to potential criminal behaviours.

What is the Personality of a Criminal?

The criminal personality type is neurotic and extroverted (a combination of all the above characteristics). They also score highly on psychoticism (i.e., cold, unemotional and prone to aggression).

Eysenck's Criminal Personality Test

Eysenck came up with his Eysenck Personality Inventory/Questionnaire (EPI/EPQ), which measures personalities, and places individuals along the E and N dimensions. He added another scale to measure psychoticism (P) later on.

The original had 57 questions options, requiring yes or no answers. There are now short versions of the questionnaire (with 48 questions) and long versions of the questionnaire (100 questions).

As previously mentioned, a high score on neuroticism, extroversion, and psychoticism is what Eysenck believed to be the personality type of a criminal.

Eysenck's Biological Theory of Personality

Eysenck claims that all our personality traits come from our nervous system. Therefore, personalities (including criminal personalities) have an innate biological basis, lending credit to Eysenck's theories, as one of the biggest struggles in psychology was establishing itself as a creditable science.

If personalities have a biological basis, they can be scientifically and empirically investigated.

Fig 2. - Eysenck suggested our genetics influences our personalities.

Eysenck suggested a genetic predisposition in people that determines their personality type. How these genes are expressed also depends on the environment, hence his theory's psychological and biological basis.

When we suggest that our biological makeup is the reason behind our decisions and actions, we take away a degree of responsibility from it. Eysenck's theory also questions if it is ethical to prosecute someone if they are helpless but to obey or fall victim to their biological drives.

Advantages of Eysenck's Personality Theory

We need to evaluate the different aspects of Eysenck's theory of personality, to assess the reliability and validity of the theory.

Advantages of Eysenck's Personality Theory

One of the major advantages of Eysenck's personality theory is that it takes a combined approach to explaining personality and crime, considering both psychological and biological factors. It can be scientifically tested, as we mentioned above.

Consider the study by Sybil Eysenck and Hans Eysenck (1977).

• They compared 2070 male prisoners with high EPI scores with 2442 male controls, divided between subgroups of ages ranging from 16 to 69 years old.
• Upon analysing the results, they found that criminals scored higher than controls over all ages on measures of psychoticism, extraversion and neuroticism.

However, David Farrington et al. (1982) reviewed this and found that though criminals scored highly on P, there was no evidence of high scores for E and N. There is also very little evidence of differences in EEG measures (which measure cortical arousal) between extroverts and introverts, making us doubt Eysenck's theory's psychological basis.

Weaknesses

Do we believe in a single criminal type? There have been many doubts about this; for example, in 1993, Terrie Moffit came up with several types of offenders based on their first crime and how long their offending persisted. Eysenck's theory also doesn't go into enough detail.

Cultural Differences

When Curt Bartol and Howard Holanchock studied six groups (grouped based on criminal history) of Hispanic and African-American prisoners in 1979 in New York, they found that all six groups were less extroverted than the control group.

They suggested this was due to the cultural differences between this group and Eysenck's, which questions the generalisability of the criminal personality.

Can we Measure Personality?

Personality is a complex area of study, and the scale provides an infinite amount of scores that are hard to quantify and reduce into core personality types. Can we conclusively say there are the big five personality types when a person may score highly in one aspect and low in another, and these scores may differ, even very slightly, from one another?

It may not be possible to reduce personality in these groups, as suggested by Eysenck, even when applied on a scale (which adds a degree of manoeuvrability, admittedly). Also, Mischel (1988) argued that personality could be context-dependent. A person may change and react/behave differently depending on the situation they have found themselves in, so these parameters personality psychologists have attempted to establish are not stable entities.

Lack of Reliability and Oversimplification

Eysenck's theory of personality relies primarily on self-report measures, which are subject to social desirability bias, lack of honesty and introspection, and a lack of self-awareness. Thus, the theory lacks reliability. It also has issues with the parameters to which we classify criminals, as other theories imply there are more factors to a personality (Five-factor model).

Fig. 3 - Self-report measures may be subject to social desirability bias, lying to make themselves appear better.