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.Jung, C.J. (1921). Psychologischen Typen. Rascher Verlag, Zurich - translation H.G. Baynes, 1923. 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 gr