Introvert and extrovert

The concepts of introvert and extrovert were popularized, describing individuals whose interests are directed inward and outward, respectively. These terms have become fundamental in understanding personality types in psychology.
 Carl Gustav Jung Switzerland 1921 Introvert and extrovert

The concepts of introvert and extrovert were popularized, describing individuals whose interests are directed inward and outward, respectively. These terms have become fundamental in understanding personality types in psychology.