Introvert vs. Extrovert Personalities Eysenck

Introvert vs. Extrovert Personalities

Eysenck and Cattel's ideas regarding the concepts of introversion and extroversion were quite similar. Both based their concepts on the degree to which a person directs their energies either outside toward the external environment, including other people, or inside toward their inner self and their own personal experiences (Hockenberry & Hockenberry, 2004, p. 417). These personality types can be seen developing even in early childhood. "Children who are very shy and/or fearful are more likely to become introverted adults, whereas fearless children are more likely to become extroverted" (as cited in Woodward et al., 2001, p. 535). Some of the traits of those who show a high level of introversion are a person who is: quiet, private, reserved, and one who avoids new experiences. In contrast, a person who shows high levels of extraversion would be sociable and outgoing. They typically enjoy new experiences, as well as stimulating environments.

Eysenck theorized that the differences in individual personalities occurred due to biological differences in individuals. He surmised that an introvert's nervous system differed from that of the extravert's. Eysenck believed that an introvert's nervous system was more easily aroused than an extravert's.

He expanded this theory to include an individual's tendency to seek out optimal levels of arousal (Hockenberry & Hockenberry, 2004, p. 418).

In this pursuit of optimal levels of arousal, extraverts naturally seek more stimulation from their environments, than their introverted peers, as their nervous system is less easily aroused than introverts. For this reason, introverts are less comfortable in a highly stimulating environment, and seek out areas of less stimulation (Hockenberry & Hockenberry, 2004, p. 418).

In 1982, researchers Campbell and Hawley performed a study confirming Eysenck's theory, regarding the tendency of introverts and extraverts to prefer different environments. Their study of students revealed that extraverted students preferred open, noisy areas of a college library to study in, where they had opportunities to socialize with others. In contrast, the introverted students chose secluded areas of the library, often hidden by tall bookcases, so that they could work in solitude (Hockenberry & Hockenberry, 2004, p. 418). These findings supported Eysenck's theory that those that scored higher on the extraversion scale would be more attracted to areas of the environment with higher stimulation, than those who scored higher on the introversion scale.

In addition to the Eysenck noted several differences in the personality traits of those who were emotionally unstable, yet introverted or extraverted, as well as those who were emotionally stable, but again introverted or extraverted. Those who are emotionally unstable, or neurotic, and introverted are often found to be: moody, anxious, rigid, sober, pessimistic, reserved, unsociable, and quiet. While those who are neurotic, but are extraverted are often found to be: touchy, restless, aggressive, excitable, changeable, impulsive, optimistic active. There are even significant differences between extroverts and introverts that are emotionally stable. Those who are emotionally stable, but introverted are often found to be: passive, careful, thoughtful, peaceful, controlled, reliable, even-tempered, and calm. While their extroverted, emotionally stable peers are often found to be: sociable, outgoing, talkative, responsive, easygoing, lively, carefree, and in positions of leadership (Hockenberry & Hockenberry, 2004, p. 418).

These individuals are typically upbeat, optimistic and sociable, and experience more positive emotions each day than introverted peers. Canli et al., in 2001, conducted a study of 14 healthy female volunteers. During their study the participants were shown both positive and negative images.

Those who scored higher on the extraversion scale experienced more reactivity to positive images, while those women with higher levels of neuroticism had more reactivity to the negative images. These findings supported the theory that the differences in personality traits produce different reactions in the brain (as cited in Hockenberry & Hockenberry, 2004, p. 419).

Libkuman et al. (1998) found that there were differences between the two personality types and the type of stimuli that would influence the accessibility of information that was stored in memory. They theorized that stable extroverted individuals were influenced by semantic stimuli, and that neurotic introverted individuals were influenced by physical, such as graphic, phonetic or both, stimuli (p. 367).