In 1942, a mother-daughter duo Katherine Cook Briggs and Isabel Briggs Myers developed a questionnaire that classified people personalities into 16 types.Called the Myers-Briggs Type Indicator,or MBTI,it would go on to become one of the world most widely-used personality tests.Today, personality testing is a multi-billion dollar industry used by individuals, schools,and companies.But none of these tests, including the MBTI, the Big Five,the DiSC assessment, the Process Communication Model,and the Enneagram,actually reveal truths about personality.