The Myers–Briggs Type Indicator (MBTI) is an introspective self-report questionnaire with the purpose of indicating differing psychological preferences in how people perceive the world around them and make decisions.
who had speculated that there are four principal psychological functions by which humans experience the world – sensation, intuition, feeling, and thinking – and that one of these four functions is dominant for a person most of the time.
Jung theorized that the dominant function acts alone in its preferred world: exterior for extraverts and interior for introverts.
The remaining three functions, he suggested, operate together in the opposite orientation.
Katharine Cook Briggs began her research into personality in 1917.
Upon meeting her future son-in-law, she observed marked differences between his personality and that of other family members.
While the Jungian model offers empirical evidence for the first 3 dichotomies, it is unclear whether the Briggs had evidence for the J-P preference.