extroversion and introversion terms introduced into psychology by Carl Jung to identify opposite psychological types. Jung saw the activity of the extrovert directed toward the external world and that of the introvert inward upon himself or herself. This general activity or drive of the individual was called the libido by Jung, who removed from the term the sexual character ascribed to it by Sigmund Freud . The extrovert is characteristically the active person who is most content when surrounded by people; carried to the neurotic extreme such behavior appears to constitute an irrational flight into society, where the extrovert's feelings are acted out. The introvert, on the other hand, is normally a contemplative individual who enjoys solitude and the inner life of ideas and the imagination. The extreme introvert's fantasies give him or her libidinal satisfactions and tend to become more meaningful to him than objective reality. Severe introversion is characteristic of autism and some forms of schizophrenia . Jung did not suggest strict classification of individuals as extroverted or introverted, since each person has tendencies in both directions, although one direction generally predominates. Influenced by Jung, Hans Eysenck conducted research on large samples of individuals, creating more objective classifications for extroversion and introversion. Bibliography: See C. G. Jung, Psychological Types (tr. 1923, repr. 1970); H. Eysenck, ed., A Model for...