The 16 types system: where it came from and how it works

Jung: attitudes, functions and rationality

Jung’s Psychologische Typen came out in German in 1921, and H. G. Baynes’s English translation followed in 1923. The starting point was two attitudes, extraversion and introversion. Jung defined them by where psychic energy is directed: at the outer object or at the subject.

On top of the attitudes he put four functions: thinking, feeling, sensation and intuition. Thinking and feeling he called rational, since they rest on reasoning and judgment. Sensation and intuition he called irrational, since they work by perception. “Irrational” doesn’t mean unreasonable here; he describes those types as highly empirical.

Two attitudes times four functions gives eight combinations, such as extraverted thinking or introverted intuition, and the book describes types built from them.

He also noticed that the leading function rarely works alone. Picture a person who settles every dispute by asking what’s consistent, so thinking leads. That person still has some second habit for taking things in, say walking out to look at the actual machine (sensation) or sitting on a hunch for a week (intuition). Jung wrote that close observation invariably turns up a second, less developed function next to the leading one. Later systems call it the auxiliary function.

He was careful about the types themselves. A pure type, he said, is rare in practice. His descriptions are composites, in the way Galton’s family portraits blend many faces into one image. Types can be graded between two extreme figures, a person can look both introverted and extraverted, and where a given person lands depends a good deal on the observer. His own judgments rested on what a person feels in his conscious psychology.

So Jung offered descriptions of tendencies, with no test that drops everyone into a box. Procedures for sorting people came later, in the 1940s.

Four dichotomies, sixteen combinations

A dichotomy is a pair of opposites, and the family uses four of them. Each is easiest to see in an ordinary situation.

Extraversion and introversion ask where attention and energy go: outward, to people and events, or inward, to ideas and one’s own reactions. In everyday talk the pair has turned into “outgoing versus shy,” which is a different thing. Someone who talks easily at a party and then needs a week alone to recover from a wedding fits that everyday word and Jung’s definition differently.

The shift shows up in psychology itself: William Revelle showed in 1997 that Eysenck’s extraversion scale moved toward sociability once most of its impulsivity items were dropped from the 1975 questionnaire. The introversion and extraversion page goes into the pair in more detail.

Sensing and intuition describe how information comes in: concrete facts or the overall pattern. Two people read the same contract. One notices the dates, the clause numbers and the penalty for late delivery. The other has already formed a view of what the deal is really about and what the other side wants.

Thinking and feeling describe how decisions get made: by objective criteria or by concern for the people affected. A team has one open spot. One person lines up the criteria and counts; another asks who needs it most. Socionics calls the same pair logic and ethics.

The fourth pair is the one the branches read differently. In Jung’s book thinking and feeling are the rational functions and sensation and intuition the irrational ones, so rationality and irrationality is a dichotomy of its own, and socionics and CoreTypes use it in that sense. The Myers-Briggs system works with a pair it calls judging and perceiving and describes it as an approach to the outer world: pushing for closure or staying open to new information. Two people are looking for an apartment. One wants to decide after the third viewing; the other keeps looking, because the fourth might be better.

Pick one pole from each of the four pairs and the result is sixteen combinations (2 × 2 × 2 × 2), which is where the name comes from. Systems write them as four-letter codes, and the codes are labels. The 16 types page lists all sixteen.

How the branches split

By the time the English translation of Jung appeared in 1923, Katharine Briggs had started working out a system of her own. Her daughter, Isabel Briggs Myers, joined her, and during World War II the two produced the first version of the indicator: 1943 by the publisher’s count, 1942 in some other accounts. The name Myers-Briggs Type Indicator dates to 1956, and since 1975 the exclusive publisher has been Consulting Psychologists Press, now The Myers-Briggs Company.

The result is a questionnaire in which every question offers two options, and each person gets a code built from four preferences.

The publisher’s own history says Jung covered three of the four pairs and Briggs and Myers added the fourth. The grouping of thinking and feeling as rational goes back to Jung himself, so the fourth dichotomy has roots in his book.

What the MBTI added is a reading of it: the last letter says which kind of function a person turns toward the outside world, a judging function (thinking or feeling) for J and a perceiving one (sensation or intuition) for P. For INTJ, the Myers & Briggs Foundation lists introverted intuition as the leading function and extraverted thinking as the auxiliary.

Socionics took a separate road. Socionics was created by Aušra Augustinavičiūtė, an economist by training, who worked in Vilnius, in Soviet Lithuania, in the 1970s. The Lithuanian encyclopedia names her sources: Jung’s Psychological Types as the foundation, plus Antoni Kępiński’s theory of information metabolism and ideas from Freud, which she applied to relations between people.

Socionics also splits people along four pairs: extraversion and introversion, logic and ethics, sensing and intuition, rationality and irrationality. Its model of the psyche, called Model A, puts eight information elements (Jung’s functions in introverted and extraverted form) in a fixed order for each type, so a type is a full order of eight functions. The theory is built around relations between types as well: “dual” pairs count as the most important, and there are others, such as activation, mirror and conflict.

By biographers’ accounts, Augustinavičiūtė learned about Myers-Briggs in the mid-1980s, from a Russian translation of a book about it, and wrote a commentary on the test in 1985. Her sixteen types were already in place. Two branches reached sixteen separately, and both started from Jung’s book.

How does socionics find a type? In theory, by interview and observation, since it rejects forced-choice questionnaires. In practice, the Lithuanian encyclopedia says, the type is most often found by watching a person or by taking an MBTI test, and early socionics tests were built on the four dichotomies.

CoreTypes is related to the family through socionics. It builds on the socionics model and Jung’s functions, and it looks for the type in the meaning of live speech: a long recorded conversation and the functions that sound loudest in it, with no questionnaire.

16Personalities looks like part of the family because of its four-letter codes, and its codes can carry a fifth letter for Assertive or Turbulent. Its own framework page says it left out Jung’s cognitive functions and reworked the model with the Big Five.

The branches disagree about what a code means, and one example shows it. Take introverted intuition in first place and extraverted thinking in second. The Foundation writes that pair as INTJ. Socionics writes it INTp, with a lowercase p. The difference is the last letter: the MBTI reads it from the function facing outward, which is thinking, a judging function, hence J. Socionics reads it from the first function, intuition, which is irrational, hence p.

The socionics type INTj has a different order, with introverted thinking first and extraverted intuition second. So someone coded INTJ in the MBTI lines up with the first two functions of socionics INTp, and INTj is a different pair. Sources also describe the match between the types of the two systems as disputed, so neither code translates the other. The cognitive functions page explains the eight functions behind these codes.

Are the types real? What the checks found

Two questions get mixed up in this debate. The first is whether the scales measure something steady. The second is whether people fall into separate types. The answers differ.

On the first, the answer is mostly yes. A 2002 meta-analysis by Capraro and Capraro found strong internal consistency and good retest reliability in the MBTI scales, with variation between studies, and the publisher reports similarly high figures for its own.

The second question is where the trouble starts. If types were separate groups, scores would pile up near the two poles of each scale and thin out in the middle: two humps instead of one. Pittenger, in a 1993 review, found no evidence of that for the MBTI. Most people score somewhere between the extremes.

In 1989 McCrae and Costa compared the MBTI with a personality inventory in 468 adults and found no support for the idea that it measures truly dichotomous preferences or qualitatively different types. What it measured was four relatively independent scales, which they tied to four of the five big traits of the Five-Factor Model.

A scale with a cutoff turns a continuous score into a category. Someone a point or two on one side of the line gets one letter, and a nearly identical person a point or two on the other side gets the opposite one. The scale can be very stable and the letter can still flip.

That’s what the retest figures show. Pittenger reported that in several studies up to half of people were placed in a different type after as little as five weeks. The publisher’s own facts page says about half get the same four-letter type on retest, and that when one letter changes it’s usually the least clear preference. The critic and the publisher land in the same place.

Picture Marta, who takes the test on a Monday and gets INFP. A month later she takes it again and gets ENFP. Nothing in her life changed. On the extraversion and introversion scale she sat close to the middle both times, and on the second attempt a couple of answers went the other way. The scores on that scale were a few points apart, and the cutoff sat between them.

The publisher defends the instrument. By its own account the MBTI is descriptive and not predictive, its validity is documented across thousands of peer-reviewed journals, and inconsistent results mostly come from preferences that are unclear.

On one point the publisher and the Myers & Briggs Foundation draw a firm line: the MBTI isn’t meant for choosing job candidates, and the Foundation calls screening applicants with it unethical.

Socionics stands on shakier ground. The Visuotinė lietuvių enciklopedija, a Lithuanian general encyclopedia, says assessments of its scientific status range from a branch of psychology to complete rejection, and that it’s most often called a pseudoscience.

So the answer to “are the types real” depends on what’s meant by real. The differences the scales pick up are real and measurable. The data show scores spread along a continuum, with no sixteen separate groups.

Why a self-report test says what it says

Every MBTI-style questionnaire records how a person sees themselves. The publisher itself says the only way to find an MBTI type is a self-report in which the person chooses between two options, and the Foundation calls the outcome preferences. That’s an honest description, and it sets a limit on what a result can tell.

The wording of a question shapes the answer. Norbert Schwarz’s 1999 review in American Psychologist gathers evidence that the format and context of questions steer self-reports. “I like to keep my options open” is easy to agree with, and “I put off decisions” sounds worse, though the two lines can describe the same person.

Stakes change answers too. A meta-analysis of 33 studies by Birkeland and colleagues (2006) found that job applicants score higher than other test-takers on traits such as extraversion, conscientiousness and emotional stability, and that the pattern shifts from one job to another; in sales it looks different. Those were Big Five questionnaires, and the MBTI wasn’t among them. Still, anyone filling in a form before a sales interview has a reason to pick the sociable answer.

Then there’s recognition. Pittenger notes that type descriptions are mostly flattering and vague enough for most readers to accept them as their own, a pattern known as the Barnum effect. A survey at the Army War College, cited in the 1991 National Academy of Sciences review, found that most participants said their results confirmed what they already knew about themselves. Recognition shows up whether the description is accurate or only agreeable.

That limit comes with the format of the questionnaire itself.

There’s another way to look for a type. CoreTypes starts from the idea that an answer to a question about yourself shows how you see yourself, while the type itself comes through in the meaning of what you say: what you notice first and what you keep coming back to without being asked. The free CoreTypes test is built on the same idea. It has 36 questions, each with four answers: sets of words, ready-made phrases or a short scene. It takes about ten minutes and doesn’t ask you to sign up, and the result is one of 16 types with a free type page. Take the CoreTypes test.

How to read a result

Start with the scores and leave the code for later. Most tests show how far each pole won on each of the four dichotomies. A narrow win is a lean, and a wide one is a tendency worth trusting more. The publisher grades the clarity of a preference from slight to very clear.

A dichotomy near the middle isn’t a verdict. Say the thinking and feeling split comes out 52 to 48. The test still has to put that person in one box, and a different week can move the result. The publisher notes that when a letter changes on a retest, it’s usually the least clear preference.

Next, read the neighboring type, the one that differs on the dichotomy that came out close. Take someone who got ENTP on one test and ENFP on another. If the two thinking and feeling scores are close, both descriptions will partly fit. The two types differ by one pole only, so that’s where the doubt naturally falls.

Take it again on another day, preferably in a different mood. The publisher itself advises a retake for anyone who’s unsure of their type or whose first result may have been shaped by events in their life. Compare the scores on each dichotomy; the two codes are the less informative part.

The 1991 National Academy of Sciences review was skeptical of the MBTI in career counseling. It added that if the data stayed negative, the test could still be used to teach how uncertain it is to sort people into categories.

The 16 types page collects the types and the tests. Next time, write down the four scores as well as the code, and compare them with a second attempt a week later. Where the same pole wins by a wide margin both times, there’s something solid to build on. Where it flips, read both neighbors.