Extraversion and introversion were popularised by Swiss psychoanalyst Carl Jung (1875-1961) in 1921. In Psychological Types, Jung described how extraverts engage with external stimuli (Jung, 1921). He believed that extraverts direct their energy outwards - towards other people - and gain energy from such encounters.

Who created introversion and extraversion?

Introvert and extravert, basic personality types according to the theories of the 20th-century Swiss psychiatrist Carl Jung.

What causes introversion and extroversion?

He said the differences between these personality types are essentially down to energy. Extroverted people often receive energy by social interactions, while introverts need time alone to recharge. ... Introverts have a lot of the chemical that makes them feel stimulated; extroverts don't have so much.