The 16 types explained: what the four letters mean

A century-old idea

In Psychological Types (1921), the Swiss psychiatrist Carl Jung proposed that people differ in two attitudes, extraversion and introversion, and in which of four mental functions they rely on: sensing, intuition, thinking and feeling.

Katharine Cook Briggs and her daughter Isabel Briggs Myers spent decades turning Jung's ideas into a questionnaire. They added a fourth preference, Judging or Perceiving, to show which function a person uses in the outer world, which produced sixteen types. Their indicator was first published in 1962 and grew into one of the most widely used personality questionnaires in the world.

The four-letter codes are now used far beyond the original instrument, including on this site. We use them as a shared vocabulary, measured with our own independent test.

The four preferences

EnergyExtraversion (E) or Introversion (I)

Where you direct your attention and draw your energy. Extraverts tend to engage the outer world of people and activity and think out loud; introverts tend to engage the inner world of ideas and reflection and need quiet to recharge.

What it is not. Introversion is not shyness. Shyness is worry about how others judge you; introversion is a preference for less stimulation. Plenty of introverts are socially confident, and plenty of extraverts are shy.

PerceptionSensing (S) or Intuition (N)

What kind of information you trust and notice first. Sensing types attend to concrete facts, details and experience; intuitive types attend to patterns, meanings and possibilities. On Koseiha we call the Sensing pole Observant.

What it is not. Intuition is not intelligence, and Sensing is not simplicity. Both describe where attention goes first, not how well anyone thinks.

DecisionsThinking (T) or Feeling (F)

What carries the most weight when you decide. Thinking types lean on impersonal logic and consistency; feeling types lean on values and the effect on people.

What it is not. Thinking types have feelings and Feeling types can reason. The preference is about which consideration tends to win when the two pull in different directions.

StructureJudging (J) or Perceiving (P)

How you like to run your outer life. Judging types prefer plans, decisions and closure; perceiving types prefer flexibility, open options and adapting as they go. In type theory, this letter also signals which of your middle two functions you use in the outer world.

What it is not. Judging does not mean judgmental, and Perceiving does not mean perceptive or lazy. They describe a preference for settled versus open-ended ways of working.

How common each preference is

E Extraverted 38.8%61.2% Introverted I
N Intuitive 31.5%68.5% Observant S
T Thinking 52.1%47.9% Feeling F
J Judging 52.5%47.5% Perceiving P

Source: MBTI Global Step I results for a US sample of 3,578 adults, matched to US census targets (Schaubhut et al., 2018). Shares differ between countries, age groups and samples.

Sixteen combinations

Two options on each of four preferences make sixteen types. In the classic table below, neighboring cells differ by one letter. The types also fall into four families that share a core motivation: Strategists (NT), Seekers (NF), Keepers (SJ) and Improvisers (SP).

STSFNFNT

IJISTJAnchor ISFJSteward INFJLamplighter INTJCartographer

IPISTPTroubleshooter ISFPArtist INFPWayfarer INTPCodebreaker

EPESTPScout ESFPSpark ENFPCatalyst ENTPTrailblazer

EJESTJQuartermaster ESFJHearthkeeper ENFJTorchbearer ENTJCaptain

Source: MBTI Global Step I results for a US sample of 3,578 adults, matched to US census targets (Schaubhut et al., 2018). Shares differ between countries, age groups and samples.

What the research says

The scales are real. When researchers compared type scores with the Big Five, four of the five traits lined up: Extraversion with E-I, Openness with S-N, Agreeableness with T-F and Conscientiousness with J-P (McCrae and Costa, 1989). The four preferences describe genuine, fairly stable differences between people.

The types are a simplification. Scores on each scale form a smooth continuum with most people near the middle, not two separate groups. Splitting at the midpoint means two people one point apart can get different letters, and people who score near the middle often change a letter when they retake a test (Pittenger, 2005).

One major trait is missing. The four letters say nothing about Neuroticism, how strongly a person reacts to stress and negative emotion, which is one of the best predictors of wellbeing in the research literature.

How Koseiha uses it

We keep the letters because they are memorable and give people a useful language for their differences. But we show every letter with its percentage, call close results close, add a fifth scale for Composure, and translate everything into the Big Five. Read the full details on how the test works.

Myers-Briggs Type Indicator, Myers-Briggs and MBTI are trademarks or registered trademarks of The Myers-Briggs Company. Koseiha is independent and is not affiliated with or endorsed by The Myers-Briggs Company.