Personality Type or Psychological Type are terms most commonly associated with the model of personality development created by Isabel Briggs Myers (aka Briggs Meyer, Meyer Briggs, Briggs Myers, Myer Briggs) the author of the world’s most widely used personality inventory, the MBTI or Myers-Briggs Type Indicator. ® Myers and her mother, Katharine Briggs, developed their model and inventory around the ideas and theories of psychologist Carl Jung, a contemporary of Sigmund Freud and a leading exponent of Gestalt personality theory.