The one-sentence summary

This is the story of the Myers-Briggs, and how personality testing took over the world.

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  • First conceived in the 1920s by the mother-daughter team of Katherine Briggs and Isabel Briggs Myers, a pair of aspiring novelists, the Myers-Briggs Type Indicator (often called the MBTI) is the most popular personality test in the world. Its language of extraversion vs. introversion and thinking vs. feeling has seeped into everything from job specifications to online dating. And yet despite the test’s widespread adoption, experts struggle to explain its success – or even validate its results.
  • Isabel was born in 1897 and died in 1980, at which point her son donated her personal papers to the Center for Application of Psychological Type (CAPT) in Florida – a non-profit research centre that she had helped to found. CAPT is now the guardian of the type indicator’s trade secrets and protector of Isabel’s legacy.
  • Sometime in the 1940s the women designed a lengthy and ingenious questionnaire that assessed one’s personality based on extraversion (E) and introversion (I), sensing (S) and intuition (N), thinking (T) and feeling (F), and judging (J) and perceiving (P).
  • As a mother, Katherine conducted a “cosmic laboratory of baby training,” using Isabel as a guineapig for various rules and tests to instil obedience and curiosity. She was very religious and had some pretty extreme views such as describing unlearned people as ‘primitive scum’ and claiming that “… the lower orders of men are far closer to the higher animals than to the higher orders of men.”
  • In 1923 she discovered the writing of Carl Jung which led to a dangerous private obsession. She bombarded him with letters, took some of his thinking to inform the test (adding much of her own), and eventually met him. Claims that the type indicator is based on Jungian principles are tenuous.
  • Meanwhile Henry Murray, director of the Harvard Psychological Clinic and a friend of Jung, was developing personology – a character assessment also based on a Jung-style questionnaire. The notion of ‘typing’ was gaining momentum.
  • Around 1943, Isabel produced “Form A” of the “Briggs-Myers Type Indicator.” Even to this day you are not allowed to call it a test. It’s a profiling grid plotting your type based on answers to the questions, and it generates four-letter types, such as EITJ, described as a thinker with an open mind.
  • By now Murray was working for the US government at a precursor of the CIA called the Office of Strategic Services (OSS). They profiled people to see if they were suitable to be spies, and assessed people like Hitler from afar. After the war, Isabel worked for a company selling tests, including her own, but made little money. Eventually she received a commission to analyse 5,000 medical students in a large-scale study. She still did the assessments by hand.
  • The IPAR (Institute of Personality Assessment and Research) took the type indicator to the west coast under the instruction of director Donald MacKinnon. Testing became big business, beginning with those such as the Scholastic Aptitude Test (SATs – still in use today) generated by the Educational Testing Service (ETS).
  • When Isabel was 75, her daughter died of an embolism after a tummy tuck operation.
  • A small test publication company called Consulting Psychologists Press (CPP) started selling the indicator in 1975 and revenues climbed swiftly. By 1979 they had sold over a million copies and by 2000, they were selling 2 million a year.
  • Currently to obtain a hard copy of the test, you need to spend over $2,000 on a weeklong certification programme run by the Myers & Briggs Foundation – the sister organisation of CAPT.


  • This is a very detailed mixture of biography and history so it takes some effort to pull out just the salient facts for those who want to know the lineage of today’s type indicator.