Knowing yourself, as well as truly understanding the people around you, their motivations, strengths and shortcomings is a superpower that can help you achieve any goal you might have. And the good news is, unlike other superpowers, it can be learned. Here is how.

To recap how the MBTI system works under the hood: everyone has a stack of cognitive functions. There are observer functions (intuition or sensing) through which you perceive and interpret the world; and decider functions (thinking or feeling) which you predominantly use to make decisions.

Observer functions:

  • Introverted sensing (Si): organizing facts
  • Extroverted sensing (Se): exploring new experiences
  • Introverted intuition (Ni): organizing ideas
  • Extroverted intuition (Ne): exploring new ideas

Decider functions

  • Introverted thinking (Ti): what works?
  • Extroverted thinking (Te): what works for the tribe?
  • Introverted feeling (Fi): what do I value?
  • Extroverted feeling (Fe): what does the tribe value?

How to type anyone

Typing someone means identifying their cognitive function stack.

Now, for the sake of simplicity, we're only focusing on the first two cognitive functions, namely the dominant function and the auxiliary function, because the other functions follow from that anyway.

There are a few simple rules for this:

  1. Everyone has one dominant cognitive function and one auxiliary cognitive function that assists the dominant function.
  2. One of these two functions is a decider function (thinking or feeling) used to make decisions, and the other is an observer function (sensing or intuition) used to perceive and understand the world.
  3. One of the two functions is predominantly used to engage with the world: extroverted; while the other one is mainly used to engage with the self: introverted.

The type of dominant function determines whether the personality is an observer (sensor or intuitive) or a decider (thinker or feeler). The direction of the dominant function determines whether the personality is considered introverted or extroverted.

So you're going to have to identify two main functions, one main observer function and one main decider function. One of these is extroverted and the other is introverted. One of them is dominant and the other is auxiliary.

Here's how you do it in 5 steps.

Step 1: relative imbalance

The first step is to look at the relative imbalance in the function stack.

Considering that the dominant function is the most overdeveloped, the imbalance between that function and its opposite on the bottom of the function stack is considerably greater than the imbalance between the two middle functions, and so it's easiest to identify.

So you find out whether someone is an observer or a decider dominant by determining on which plane this person is most 'out of whack'.

If someone is an observer dominant, the relative imbalance will be in the observer functions: sensing versus intuition. For observers, life is about things, either ideas or facts. In their bad moments, they're mainly overcome by chaos and they want control. They're relatively comfortable with their own position in the tribe.

But if someone is a decider dominant, the relative imbalance will be in the decider functions: thinking versus feeling. For deciders, life is about people, the self and the tribe. In their bad moments, they're overcome by questions about their own identity and position in the tribe. They're relatively comfortable with chaos.

A decider dominant will jump back and forth between the abstract world of ideas and concrete reality really easily, because their observer functions are relatively balanced. Conversely, an observer dominant will jump back and forth between thinking and feeling relatively easily, because their decider functions are relatively balanced.

Step 2: introvert or extrovert

Once you have figured out whether this person is an observer or a decider, it's time to figure out whether they're introverted (focused on the self) or extroverted (focused on the tribe).

For a decider, the extroverted decider (Te or Fe) will be focused outside, on the tribe, for the decision making, and will be craving tribe validation. The introverted decider will be more focused on the self.

For an observer, the extroverted observer (Ne or Se) will mostly be focused on variety and gathering the new from the outside world, whereas an introverted observer (Ni or Si) will be focused on what they already have and organizing that.

Step 3: weaknesses

Once you have determined whether the person you're typing is an observer or decider dominant, you can figure out their exact dominant function by their inferior function. This way, you find out what someone is by eliminating what they definitely aren't.

For example, if someone seems to always neglect taking care of rudimentary things like insurance or the laundry; because they're living in a world of ideas and possibilities, they probably have inferior sensing and are a dominant intuitive.

And if someone  is the most social person you ever met but they can't handle money to save their lives, they're probably a feeler.


It should not be hard to find the inferior function, thereby finding the dominant function. If it is, you probably did something wrong at step 1 and you should start over.

Step 4: auxiliary function

Figuring out the auxiliary function should be pretty straightforward at this point, because you know how it compliments the dominant function.

If your dominant function is an observer, the auxiliary is a decider and vice versa. And if your dominant function is extraverted you know the auxiliary function must be introverted and vice versa.

So you should only have two functions left to choose from.

Step 5: bring it all together

Now that you have determined the top two functions in the stack, you have your personality type figured out and you can translate it to the four letter code.

  • The first letter is the direction of the dominant function, either Introverted or Extroverted.
  • The second letter is the main observer function, either iNtuition or Sensing.
  • The third letter is the main decider function, either Thinking or Feeling.
  • The fourth letter is determined by the which of your functions is extroverted, Judging for an extroverted decider and Perceiving for an extroverted observer.

And there you have it: your personality type.

Now that you have identified your own type, it's time to start working on yourself. After all, typing yourself is akin to diagnosing yourself with a mental disorder. Curious what I mean by that? Read my next article on MBTI.