Understanding the Myers-Briggs Type Indicator

The real MBTI is both much more valuable and much more complicated than what most people know. It’s based around the concept of cognitive functions: our (subconscious) preferences for the way we pick up on and process information. It takes a while to figure it out, but once you do it’ll open up a world of new possibilities.

The first thing you need to know is that there are two kinds of functions:

  • Functions you use to obtain information are called perceiving functions.
  • Functions you use to process information are called judging functions.

Perceiving functions

There are two types of perceiving functions:

  • When we literally observe (for instance: we notice the grass is green) we use our Sensing functions. These are indicated with the letter S.
  • When we observe through a prism of symbolism and patterns we use our Intuitive functions. These are indicated with the letter N.

Judging functions

There are also two types of judging functions:

  • When we value objective criteria above subjective criteria (for instance consistency over being nice) we use our Thinking. This is indicated with the letter T
  • When we observe through a prism of symbolism and patterns we use our Feeling This is indicated with the letter F.

Introverted and extraverted functions

Every function (sensing, intuitive, thinking and feeling) can be either introverted or extraverted. Extraverted functions focus on the outside, introverted functions focus on the inside. Whether a function is extraverted or introverted is indicated with a lowercase e or i. This results in the following 8 functions:

  • Se: extraverted sensing: focusing on what you see, touch, taste, hear and smell. 
  • Si: introverted sensing: focusing on what you remember or what you feel in your body (body awareness).
  • Ne: extraverted intuition: focusing on patterns and symbolism of external information (things happening around you).
  • Ni: introverted intuition: focusing on patterns and symbolism of internal information (hunches, dreams).
  • Fe: extraverted feeling: focusing on harmony with others, relationships between people.
  • Fi: introverted feeling: focusing on your personal values (‘this is the right thing to do’).
  • Te: extraverted thinking: focusing on achieving specific goals.
  • Ti: introverted thinking: focusing on internal consistency in thinking patterns.  

The functional stack

We all use every one of our 8 functions. However, we tend to have our preferences: functions we’re better at, functions we’re worse at. Functions that are our ‘kneejerk reaction’, whether in a  good way or in a bad way. This is called our functional stack. 

The first function in our stack is called our dominant function. The second function is called our auxiliary function. The third one is called our tertiary function. The last one is called our inferior function. 

To determine your stack, you need to know a few things:

  • A cognitive stack has 4 out of 8 functions. For every type of function, the stack contains EITHER the extraverted OR the introverted variety, never both.
  • The dominant and inferior function are EITHER both perceiving OR both judging. The same goes for the auxiliary and tertiary function. 
  • The cognitive functions in a stack alternate: extraverted-introverted-extraverted-introverted or introverted-extraverted-introverted-extraverted.

This means a functional stack can be for instance: Ne – Ti – Fe – Si (hint, this is the stack for ENTPs).

Type names

Every type in MBTI has their own functional stack. Based on the functional stack you can determine the name and the other way around. This is a bit less straightforward than you might think…

The first letter is an i or an e depending on whether your dominant function is introverted or extraverted. In the example above, we have Ne as our dominant function, giving us an E as the first letter.

The second letter is your highest perceiving function (so in the stack above that would be an N).

The third letter is your highest judging function (in the stack above, that would be a T).

The fourth letter is the hardest: it’s a P if the highest extraverted function is a Perceiving function and it’s a J if the highest extraverted function is a Judging function (which is why it often determines what others see of us: our interaction with the outside world). In the example above, our highest extraverted function is Ne, a perceiving function, which is why the fourth letter is a P.


That’s been a lot of information but now you have a solid understanding of what these letters actually mean. One last thing: as you may have noticed, MBTI uses a lot of words in a slightly different way than what you might be used to. So just to recap…

  • Feeling in MBTI means focusing on subjective rather than objective criteria, not on being more emotional or more social or on physical feelings.
  • Thinking in MBTI means focusing on objective rather than subjective criteria, not being smarter, more intelligent or knowing more. 
  • Sensing in MBTI means relying on your five senses, bodily sensations and memory. It doesn’t refer to a sixth sense or being able to pick up on hunches (that’s actually intuitive).
  • Judging in MBTI refers to the fact you focus on processing information. It’s not about judging others or condemning people.
  • Introverted and extraverted indications refer to an outward or inward focus. They have nothing to do with being outgoing or social.


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Hi all, like many of you, I've been an ENTP my whole life. I have experienced the pleasure of changing my major several times, quitting a PhD, starting (but not finishing) a novel, and finding a career that actually suits me. I'm here to share the outcomes that come from NeTi decisions with hope that my journey will help you discover (or avoid) your own interesting path. Thanks for being here; if you like my stuff hit me up @forsakingfaith on Twitter, don't mind the podcast, it's an old passion project! Much Love
Also, I do love coffee - Cheers!