Extraversion and introversion

The trait of Extraversion-Introversion is a central dimension of human personality. Extraverts (sometimes called "extroverts") are gregarious, assertive, and generally seek out excitement. Introverts, in contrast, are reserved, deep in thought, and self-reliant. They are not necessarily asocial, but they tend to have few true friends, and are less likely to thrive on making new social contacts.

The terms introversion and extraversion were popularized by Carl Jung. Virtually all comprehensive models of personality include the trait. Examples include Eysenck's three factor model, the Big Five personality traits, and the Myers Briggs Type Indicator.

Extraversion
Extraversion is "the act, state, or habit of being predominantly concerned with and obtaining gratification from what is outside the self". Extraverts tend to enjoy human interactions and to be enthusiastic, talkative, assertive, and gregarious. They take pleasure in activities that involve large social gatherings, such as parties, community activities, public demonstrations, and business or political groups. Acting, teaching, directing, managing, brokering are fields that require extraversion. An extraverted person is likely to enjoy time spent with people and find less reward in time spent alone. They enjoy risk-taking and often show leadership abilities.

An extravert is energized when around other people. Extraverts tend to "fade" when alone and can easily become bored without other people around. Extraverts tend to think as they speak. When given the chance, an extravert will talk with someone else rather than sit alone and think.

Introversion
Introversion is "the state of or tendency toward being wholly or predominantly concerned with and interested in one's own mental life". Introverts tend to be quiet, low-key, deliberate, and relatively non-engaged in social situations. They take pleasure in solitary activities such as reading, writing, drawing, watching movies, listening to music, inventing, designing, programming and using computers extensively. The archetypal artist, writer, sculptor, composer and inventor are all highly introverted. An introverted person is likely to enjoy time spent alone and find less reward in time spent with large groups of people (although they tend to enjoy interactions with close friends, and are in many cases married). They prefer to concentrate on a single activity at a time and like to observe situations before they participate.

Introversion is not the same as shyness, though introverts may also be shy. Introverts choose solitary over social activities by preference, whereas shy people avoid social encounters out of fear.

An introvert is energized when alone. Introverts tend to "fade" when with people and can easily become overstimulated with too many others around. Introverts tend to think before speaking. When given the chance, an introvert will sit alone and think rather than talk with someone else.

Ambiversion
Although many people view being introverted or extraverted as a question with only two possible answers, trait theories such as the Big Five treat levels of extraversion as part of a continuum, with some scores very close to either end and others near the half-way mark.

Ambiversion is a term used to describe people who fall more or less directly in the middle and exhibit tendencies of both groups. An ambivert is normally comfortable with groups and enjoys social interaction, but also relishes time alone and away from the crowd.

Measurement
Extraversion-introversion is normally measured by self-report. A questionnaire might ask if the test-taker agrees or disagrees with statements such as I am the life of the party or I think before I talk.

Imagine a questionnaire consisting of ten "agree or disagree" statements. For the first five questions, agreement indicates a tendency towards extraversion, while for the last five questions, agreement indicates introversion. Five people take this questionnaire and answer as follows:

In this example, John and Maria are extraverted, Sarah and David are introverted, and Marcus is neither.

Self-report questionnaires have obvious limitations in that people may misrepresent themselves either intentionally or through lack of self-knowledge. It is also common to use peer report or observation.

Another approach is to present test-takers with various sets of adjectives (for example: thoughtful, talkative, energetic, independent) and ask which describes them most and least. Psychological measures of this trait may break it down into subfactors including warmth, affiliation, positive affect, excitement seeking, and assertiveness/dominance seeking.

Jungian theory
According to Carl Jung, introversion and extraversion refer to the direction of psychic energy. If a person’s energy usually flows outwards, he or she is an extravert, while if this energy normally flows inwards, this person is an introvert. Extraverts feel an increase of perceived energy when interacting with a large group of people, but a decrease of energy when left alone. Conversely, introverts feel an increase of energy when alone, but a decrease of energy when surrounded by a large group of people.

Most modern psychologists consider theories of psychic energy to be obsolete. First, it is difficult to operationalize mental "energy" in a way that can be scientifically measured and tested. Second, more detailed explanations of extraversion and the brain have replaced Jung's rather speculative theories. Nevertheless, the concept is still in popular usage in the general sense of "feeling energized" in particular situations. Jung’s primary legacy in this area may be the popularizing of the terms introvert and extravert to refer to a particular dimension of personality.

Jung's theory was influential in the development of the Myers Briggs Type Indicator and Aushra Augusta's theory of socionics.

Eysenck's theory
Hans Eysenck described extraversion-introversion as the degree to which a person is outgoing and interactive with other people. These behavioral differences are presumed to be the result of underlying differences in brain physiology. Extraverts seek excitement and social activity in an effort to heighten their arousal level, whereas introverts tend to avoid social situations in an effort to keep such arousal to a minimum (see Differences in brain function below). Eysenck designated extraversion as one of three major traits in his P-E-N model of personality, which also includes psychoticism and neuroticism.

Eysenck originally suggested that extraversion was a combination of two major tendencies, impulsiveness and sociability. He later added several other more specific traits, namely liveliness, activity level, and excitability. These traits are further linked in his personality hierarchy to even more specific habitual responses, such as partying on the weekend.

Eysenck compared this trait to the four temperaments of ancient medicine, with choleric and sanguine temperaments equating to extraversion, and melancholic and phlegmatic temperaments equating to introversion.

Nature vs nurture
The relative importance of nature versus environment in determining the level of extraversion is controversial and the focus of many studies. Twin studies find a genetic component of 39% to 58%. In terms of the environmental component, the shared family environment appears to be far less important than individual environmental factors that are not shared between siblings.

Differences in brain function
Eysenck proposed that extraversion was caused by variability in cortical arousal; "introverts are characterized by higher levels of activity than extraverts and so are chronically more cortically aroused than extraverts". Because extraverts are less aroused internally, they require more external stimulation than introverts. This theory may be backed up by evidence that the brains of extraverts are more responsive to dopamine than those of introverts. Other evidence of this “stimulation” hypothesis is that introverts salivate more than extraverts in response to a drop of lemon juice.

One study found that introverts have more blood flow in the frontal lobes of their brain and the anterior or frontal thalamus, which are areas dealing with internal processing, such as planning and problem solving. Extraverts have more blood flow in the anterior cingulate gyrus, temporal lobes, and posterior thalamus, which are involved in sensory and emotional experience. This study and other research indicates that introversion-extraversion is related to individual differences in brain function.

Implications
Acknowledging that introversion and extraversion are normal variants of behavior can help in self-acceptance and understanding of others. For example, an extravert can accept her introverted partner’s need for space, while an introvert can acknowledge his extraverted partner’s need for social interaction.

Social psychologist David Myers found a correlation between extraversion and happiness; that is, more extraverted people reported higher levels of personal happiness. These findings may prove misleading if the introvert's near-constant introspection and resulting deeper self-knowledge are taken into account, as compared to the extravert's less substantial ideas of the meaning of personal happiness. According to Carl Jung, introverts acknowledge more readily their psychological needs and problems, while extraverts tend to be oblivious of them because they are focused on the outside. Possibly, the results reflect biases in the survey itself. It could also be due to the fact that introversion is often regarded as depreciatory in Western culture. On average, extraverts also have a somewhat higher self-esteem than introverts. As in the case of happiness, this may be due to inherent differences in the brain, or differential social treatment.

Extraversion is perceived as socially desirable in Western culture, but it is not always an advantage. For many years, researchers have found that introverts tend to be more successful in academic environments, which extraverts may find boring. Extraverted youths are also more likely to engage in delinquent behavior.

Career counselors often use personality traits, along with other factors such as skill and interest, to advise their clients. Some careers such as computer programming may be more satisfying for an introverted temperament, while other areas such as sales may be more agreeable to the extraverted type.

Although neither introversion nor extraversion is pathological, psychotherapists can take temperament into account when treating clients. Clients may respond better to different types of treatment depending on where they fall on the introversion/extraversion spectrum. Teachers can also consider temperament when dealing with their pupils, for example acknowledging that introverted children need more encouragement to speak in class while extraverted children may grow restless during long periods of quiet study.

However, use of the terms may encourage pigeonholing or stereotyping. As noted above, extraversion may be a continuum and many people have a mixture of both orientations in their personalities. A person who acts introverted in one scenario may act extraverted in another, and people can learn to act “against type” in certain situations. Jung's theory states that when someone's primary function is extraverted, his secondary function is always introverted (and vice versa).