Developed by Isabel Briggs Myers and her mother Katharine Briggs and first published in 1962, the Myers-Briggs Type Indicator has become very popular in occupational settings. Based on Carl Jung’s theory of personality types, the Myers-Briggs classifies people into one of sixteen personality types depending on their scores on four dichotomies (pairs of opposites).

The first dichotomy, extraversion (E) vs. introversion (I), measures the degree to which someone is oriented toward the external, social world or toward their own inner thoughts and reflections. The second dimension, sensing (S) vs. intuition (N), refers to the way people gather information: Do they focus on concrete facts, or do they try to organize information into patterns? The third dimension, thinking (T) vs. feeling (F), relates to the way people make decisions: Do they focus more on facts and principles or on interpersonal concerns? The final dimension, judging (J) vs. perceiving (P), relates to the way that people come to closure: Do they prefer to come to a decision, or do they prefer to keep their options open, continuing to gather new information?

The sixteen personality types are identified by their initials (e.g., ENTJ, INFP, ESFJ) and have been linked to specific occupations. For example, people who score high on extraversion (E) might make good salespeople while people who score high on sensing (S) might make good mechanics. Although this test makes good intuitive sense—that is, it appears to make sense-it has been criticized as lacking adequate scientific validation. Despite these criticisms, the test remains very popular in many settings.