“Jungian” refers to the analytical psychology founded by Swiss psychiatrist Carl Gustav Jung (1875–1961). Early in his career Jung conducted experiments in mental association and through this work came into contact with famed psychoanalyst Sigmund Freud (1856–1939) in 1907. While initially in harmony with each other, Jung later broke with Freud’s theories, establishing his own doctrines of human behavior.

Like Freud, Jung believed that the unconscious (that part of the mind of which a person is unaware) affects human behavior. But unlike his Austrian colleague, Jung denied that neuroses have any sexual basis. Instead, Jung believed that many factors influence human behavior, including the personalities of one’s parents. He also believed in something he described as the “collective unconscious”: In his revolutionary work Psychology of the Unconscious, published in 1912, Jung asserted that there are two dimensions of the unconscious: the personal and the collective. The collective unconscious, according to Jung, is made up of those acts and mental patterns that are shared by members of a culture or are perhaps universally shared by all humankind. He theorized that the collective unconscious manifests itself in archetypes—images, patterns, and symbols that appear in dreams and fantasies as well as in mythology, religion, and literature. Jung believed that the collective unconsciousness can serve as a guide to humanity and, therefore, he taught that therapy should make people aware of it. Jung’s theories of archetypes, or universal symbols, have influenced such diverse fields as anthropology, art, filmmaking, and history.

Jung later developed a system for classifying personalities (into introverted and extroverted types) and distinguishing among mental functions (classifying them as thinking, feeling, sensing, or intuitive). Jung taught that therapists should help their patients balance introversion (relying only on oneself for personal fulfillment) with extroversion (relying on others for personal fulfillment). Jung’s system of classifications, or “typology,” has been used to develop theories of personality types and their influences on human behavior.