Hank describes Congresswoman Welch as being "ISTP on the old Myers-Briggs, which is still the gold standard for personnel." Hank is referring to the Myers-Briggs Type Indicator (MBTI) system, a personality test developed during World War II by Americans Katharine Cook Briggs and her daughter Isabel Briggs Myers, based on psychiatrist
Carl Gustav Jung's 1921 book "Psychological Types", with the goal of helping women entering the industrial workforce for the first time identify war-time jobs to which they may be well-suited. The system categorizes individuals into 16 distinct "personality types" by assigning a letter to a set of four categories: Extraversion or Introversion, Intuition or Sensing, Feeling or Thinking, and Judgment or Perception. The letters are assigned based on a series of questions the subject answers, producing a four-letter test result, such as "ISTP" in the case of Congresswoman Welch. ISTP indicates she exhibits Introversion, Sensing, Thinking, and Perception. According to the MBTI, an ISTP is a "craftsperson" and "virtuoso"; they are people who are logical, hands-on, action-oriented, prefer spontaneity, enjoy troubleshooting, and value their independence. Despite the MBTI still being a fairly popular personality test for the general population, often used by personal development coaches and websites, professional psychologists and psychiatrists consider it to be little more than pseudoscience and don't consider it a valid or reliable personality test for clinical purposes. The questions developed for the MBTI are vague and general enough to apply to a broad range of people (known as the Barnum effect [after
P.T. Barnum]), relying on flattery and confirmation bias to lead participants to identify with descriptions that are vague and considered desirable and applicable by society.
