WWII basically ended unemployment in the US. Increased wartime production and the drafting of millions of men had created so many new opportunities, that the effect of the great depression was finally countered. It was a time when millions of women would join the work force. They filled traditionally "female" jobs but also opened up many previously "male" jobs, from operating heavy machinery to traveling sales people. In a sense, it was a revolution stemming from necessity, which is often the case even when the necessity doesn't arise because of a world war; someone's next promotion might occur with the same dynamic.
It was in this atmosphere that Katharine Cook Briggs and her daughter, Isabel Briggs Myers, started working on a personality type test that would help new female workers find the right job for them, where they could be more effective. More than 60 years later, MBTI is a commonly used test to assess personality types and help people of various preferences understand each other's perspective of ideas, data, decision making and planning, among others.
