There are many theories regarding what makes someone an extrovert or an introvert. Many people assume these terms refer to an individual who is either shy or sociable, but Carl Jung believed this is only part of the characteristics.
Extroverts have an ego that faces more towards the persona (our public image). This means that extroverts place more emphasis on external gratification such as people, money and activities. Jung believed that society, incorrectly, values extroverts more than introverts.
For introverts the emphasis is on the the internal world of feelings, dreams , fantasies and thoughts. Jung believed that introverts have an ego that faces more towards the collective unconscious and it’s archetypes. Jung saw introverts as being much more mature than extroverts.
Hans Eysenck developed Jung’s theories during the 1960′s and often referred to introversion and extroversion as “sociability” and “surgency”.