Keirsey's Fieldmarshal Rational is not inherently "extroverted" very much, and the Inventor Rational is even less. For example, General George C. Marshall (a Fieldmarshal) and Nicola Tesla (an Inventor) would not be very good examples of the "typical" Extrovert -- they were not gregarious in the least. Sure, most Fieldmarshals and Inventors can be "gregarious" or "not shy", in fact they can be sometimes overbearing or steamrolling in their opinions. They are usually pretty friendly at parties and open to people to some extent. Although they don't have to be. Moreover, if Fieldmarshal is finding a particular person "boring" (and that can be in a few seconds) he quickly will find any excuse to exit the scene very quickly or if he finds utility in it, he can rake the person over the conceptual coals, so to make sure that person realizes he is not considered worthwhile. So the Fieldmarshal is an "extrovert" with a purpose (they are pragmatic -- their sociability is often contingent). Sometimes that purpose can be very narrow, such that the common notion of "extrovert" is not well suited for the Fieldmarshal. Same is true with the Inventor. The Inventor often appears like an Artisan Promoter, always interested in having an "interesting" time. Only the difference is the Inventor is "looking" for new experiences, new ideas, or some way to promote his ideas, so those who don't help in this endeavor are quickly cast off. That is, the Inventor is an "extrovert" with an interest (outer-directed might be a better term), and that specific interest often being so narrow that the term "extrovert" is misleading. Although in casual acquaintance they appear to be "extroverted."