The Myers and Briggs personality system is more complex than it appears at first glance. Beyond the basic four-letter structure, the overall framework of the MBTI® assessment includes eight cognitive functions, which reveal how your mind works and how you relate to the world at large. They guide your interactions with others and your environment. They also explain how your belief systems emerge and how they influence your thinking and behavior.

The cognitive functions are a useful tool for revealing the dynamic qualities of personality, translated into the actual practice of living in the real world.

The Cognitive Functions in theory and practice

The starting point is Carl Jung’s theory of cognitive functions. He identified four of them, which he labeled as sensation, intuition, thinking, and feeling. He asserted that everyone would have both a primary function and a supporting or auxiliary function and that understanding each would reveal the secrets of how each person absorbed and processed information and used it to evaluate options and make decisions.

Using Jung’s ideas as a template, Isabel Briggs Myers modified the Myers and Briggs personality typing system to include eight cognitive functions — twice as many as Jung identified.  She kept Jung’s initial four functions (identified by the letters S, N, T, and F in the Myers-Briggs typing system), but added ‘extraverted’ and ‘introverted’ options for each (signified by ‘e’ or ‘i’ in lower case).

So an ENFJ, to give one example, would have an extraverted Feeling function (Fe) and an introverted Intuition function (Ni). Conversely, an INFP would have an introverted Feeling function (Fi) and an extraverted Intuition function (Ne).

To clarify: extraverted or introverted in this case do not refer to how outgoing someone is (or isn’t). Instead, they relate to the outward or inward focus of each function. Extraverted functions express themselves through an immersion in the external world, while introverted functions are defined by a process of inner self-reflection. More on that in a moment. 

How this interacts with the four-letter personality code

Isabel Briggs Myers kept the idea of a dominant (primary) and auxiliary (supporting) function as an essential element of her system. But she gave those concepts more depth and context, through two added stipulations:

  1. For each person, their personality would determine the identity of the dominant function. In practice, this means that an Introvert will always have an introverted dominant function, while an Extravert will always have an extraverted dominant function.

  2. The cognitive functions divide into perceiving and judging categories. The perceiving functions (Sensing and Intuition) explain how people receive and absorb information, while the judging functions (Thinking and Feeling) explain how they make decisions.

Each person has one cognitive function for both the perceiving and judging categories, since both processes are required for human thinking and behavior. But Judgers will always have an extraverted-Judging function, while Perceivers will always have an extraverted-Perceiving function.

Whether or not that function is dominant depends on whether a person is an Extravert or an Introvert. Extraverted Perceivers will have a dominant perceiving function, but the perceiving function will fill an auxiliary role in Introverted Perceivers. Likewise, Extraverted Judgers will have a dominant judging function, while Introverted Judgers will have an auxiliary judging function.

All of this might sound complicated. But that’s only because people are complicated. The good news is that once you’ve decoded your personality type and identified your cognitive functions, you’ll possess valuable insights that can help you do a deep dive into your own psyche.

Who am I, Really? Introducing the Eight Cognitive Functions

Once you know your four-letter personality type, you’ll automatically know your cognitive functions, since this system of analysis has a fixed structure.

Here are quick summaries of the main personality characteristics you can expect to demonstrate, depending on the identity of your dominant and auxiliary (supporting) cognitive traits:

Extraverted Sensing (Se)

People with the extraverted Sensing function rely on their five senses to absorb as much information about their environment as they can. They are highly observant and sensitive, and notice details about what is happening around them that other people miss. They tend to be very focused on the here-and-now, preferring to live in the moment rather than thinking about what might happen next week, next month, or next year.

Extraverted sensing is the dominant cognitive function in ESTPs and ESFPs, and the auxiliary function in ISTPs and ISFPs.

Introverted Sensing (Si)

Those who have an introverted Sensing function relate past experiences to present circumstances. Sensory input (sight, sound, touch, smell, taste) is used as a frame of reference to build ideas about how the world is and how it works, which leads to strongly patterned ways of acting and responding. Men and women with an introverted sensing function are highly organized, thrive on routine, and have wonderful memories.

ISTJs and ISFJs have introverted sensing as their dominant cognitive function, while ESTJs and ESFJs feature it as their auxiliary function.

Extraverted Intuition (Ne)

People with extraverted Intuition see patterns everywhere. They notice connections between things, people, and events that others miss. Their intellects are speculative and creative, and they’re always trying to come up with new and more inclusive ideas that capture reality more fully and comprehensively. Individuals with extraverted intuition are excellent speakers and communicators who know how to carry others along with them on their imaginative excursions.

ENTPs and ENFPs have extraverted intuition as their dominant cognitive function, while INFPs and INTPs have it as an auxiliary function.

Introverted Intuition (Ni)

Those who possess introverted Intuition rely on their instincts to guide them through life. If you ask them to explain their conclusions or behavior, they often wouldn’t be able to do so logically or rationally. They are the go-with-the-flow type, content to let their subconscious minds steer them in the proper direction. They are focused inward, exploring their own minds for guidance, and very much oriented toward the future rather than the immediate moment.

INTJs and INFJs have introverted intuition as their dominant cognitive function, while ENFJs and ENTJs have it as their auxiliary function.

Extraverted Thinking (Te)

Of all the cognitive functions, extraverted Thinking is most closely associated with the relentless use of logic and reason. Emotions are set aside, and judgments are made entirely based on what seems reasonable and rational. People with extraverted thinking functions know how to compartmentalize their emotions as they make their decisions, so they don’t distort the thinking process. They are verbally adept and highly persuasive, showing the capacity to create tightly structured arguments that impress most listeners.

ENTJs and ESTJs have extraverted thinking as their dominant cognitive function, while INTJs and ISTJs possess it in its auxiliary form.

Introverted Thinking (Ti)

Those who have an introverted Thinking function are deeply analytical and logical. Their frames of reference come from their internally held belief systems, which are carefully constructed based on past insights and discoveries. They expect reality to conform to their already existing ideas, although if there are persistent conflicts they will adjust their thinking gradually over time. They reflect on everything happening around them and are reluctant to let anything go until they’re sure they understand.

INTPs and ISTPs have introverted thinking as their dominant cognitive function, while ENTPs and ESTPs have introverted thinking as their auxiliary function.

Extraverted Feeling (Fe)

Men and women with extraverted Feeling functions base their decisions on their values, which are determined through their interactions with other people and their assessments of others’ needs. Their value systems are heavily influenced by cultural and societal norms, which reveals the outward focus of their feeling function. People in this category are sensitive and empathic and will go to great lengths to help other people in any way they can.

ENFJs and ESFJs have extraverted feeling as their dominant cognitive function, while INFJs and ISFJs have is as their auxiliary function.

Introverted Feeling (Fi)

Individuals who possess introverted Feeling as a cognitive function are the most empathetic of all types. They can feel others’ pain and unhappiness as if it were their own, and they will act to relieve that pain and unhappiness if they can. Their value systems mean everything to them, and they adopt their ethics based on their own assessments rather than the opinions of others. They will do what seems right to them, regardless of prevailing cultural or societal standards.

INFPs and ISFPs have introverted feeling as their dominant function, while ENFPs and ESFPs have it as an auxiliary function.

The Seven Principles of Cognitive Function Theory, Reviewed

The Myers-Briggs cognitive function concept can be summed up by the following seven principles:

1. There are eight cognitive functions, divided into four types that can be Extraverted or Introverted: Sensing, Intuition, Thinking, and Feeling.

2. Sensing and Intuition are perceiving functions (relating to how you absorb and process information), while Thinking and Feeling are judging functions (relating to how you make decisions).

3. Each individual will have two cognitive functions, one from the perceiving category and one from the judging category.

4. Each person will have a dominant and auxiliary (supporting) cognitive function.

5. These dominant and auxiliary functions will be extraverted in one instance and introverted in the other.

6. Judgers will have an extraverted Thinking or Feeling function, while perceivers will have an extraverted Sensing or Intuition function.

7. In Extraverted people, the dominant cognitive function will be extraverted.

8. In Introverted people, the dominant cognitive function will be introverted.

Once you have a handle on these principles, you’ll understand the impact of cognitive functions on human thinking and behavior in general. When you know your personality type, you’ll understand how the cognitive functions relate to your life specifically. You’ll gain fresh insights that will increase your self-knowledge and sense of personal empowerment. 

Nathan Falde
Nathan Falde has been working as a freelance writer for the past six years. His ghostwritten work and bylined articles have appeared in numerous online outlets, and in 2014-2015 he acted as co-creator for a series of eBooks on the personality types. An INFJ and a native of Wisconsin, Nathan currently lives in Bogota, Colombia with his wife Martha and their son Nicholas.