Who Created the 16 Personalities Test?

The typological indicator now popularly known as the “16 personalities test,” or the MBTI, was created by two women with no formal academic training in psychology: a mother and daughter, working from home over more than two decades.

A mother who was cataloguing personalities before she’d even read Jung

Katharine Cook Briggs began observing and classifying differences in temperament long before she read Jung. By the early twentieth century, she’d already spent years noting behavior patterns among the people close to her, partly driven by curiosity about why her son-in-law Clarence “Chief” Myers had such a different character from her daughter Isabel, despite how well the two got along. When Carl Jung’s Psychological Types (originally published in 1921) was translated into English in 1923, Briggs found in it a theoretical framework that matched years of homemade observation.

Isabel Briggs Myers: from mystery novelist to self-taught statistician

Her daughter, Isabel Briggs Myers, had no training in psychology or statistics; she’d studied political science and spent time writing mystery novels. Even so, starting in the 1930s she began designing questions, informally testing them with people she knew, and refining the questionnaire by hand, teaching herself the fundamentals of building a psychometric test that no university program had ever taught her.

During World War II, with much of the working population mobilized and an urgent need to assign each person to the industrial job that best matched how they worked, Briggs and Myers saw an immediate practical use for their instrument and distributed the first paper versions of the questionnaire.

From homemade project to published standard

For years, the indicator remained a project carried almost single-handedly by Myers, who tested it with thousands of medical and nursing students to build up data. It wasn’t until the 1960s and 1970s, with psychologist Mary McCaulley joining the effort and the founding of the Center for Applications of Psychological Type, that the instrument gained much of the psychometric machinery (test-retest reliability, construct validity) it had lacked since its homemade beginnings, having already been formally published as a standard since the mid-1950s (see the technical details above).

The mechanics of the four dimensions

The final indicator was built around four bipolar scales, or independent dichotomies, combining Jung’s ideas with Briggs and Myers’s contributions:

• Energy orientation: Extraversion (E) versus Introversion (I). Defines whether the focus is directed at the outside world or the inner universe of ideas.
• Gathering information: Sensing (S) versus Intuition (N). Chooses between literal input through the senses or picking up on patterns and abstract possibilities.
• Making decisions: Thinking (T) versus Feeling (F). Weighs logical, impersonal analysis against evaluation based on personal or social values.
• Outward lifestyle: Judging (J) versus Perceiving (P). Describes whether a structured, decisive environment is preferred, or a flexible approach that flows with circumstances.

Crossing these variables produces a unique four-letter code (like INFJ or ESTP) describing one of the 16 portraits of normal personality.

An essential mental health note: this self-report typology is interactive, educational content for self-knowledge and personal development. It doesn’t measure pathology or intellectual aptitude, and it does not, under any circumstances, replace a diagnostic evaluation or the clinical judgment of a qualified professional.

Evolution and digital impact

What began as a family observation project became a formally published psychometric standard starting in 1956. With the rise of digital platforms, the 16-personalities assessment has become one of the most widespread methods online for career guidance and team cohesion. Its value today lies in its pedagogical ability to translate complex concepts from depth psychology into a clear, approachable, everyday-useful map.