MBTI Does Not Measure Traits or Behaviors
The following excerpts are from the "Guide to the Development and Use of the Myers-Briggs Type Indicator" by Isabel Briggs Myers and Mary H. Mccaulley:
The aim of MBTI is to identify the basic preferences of people in regard to perception and judgment. Perception involves all the ways of becoming aware of things, people, happenings, or ideas. Judgment involves all the ways of coming to conclusions about what has been perceived.
The indices EI, SN, TF, and JP are designed to point in one direction or the other. They are not designed as scales for measurement of traits or behaviors.
The intent is to reflect a habitual choice between rival alternatives, analogous to right-handedness or left-handedness. One expects to use both hands, even though one reaches first with the hand one prefers. Similarly, every person is assumed to use both poles of each of the four preferences, but to respond first or most often with the preferred functions or attitudes.