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The Theory

The foundation of the MBTI and other Type instruments is Carl Jung’s theory of personality called Psychological Types. Jung was a Swiss psychiatrist(1875-1961) and the father of analytical psychology. His theory is a dynamic theory of personality which looks at the different ways in which people most naturally focus their psychological energy or awareness.

Jung postulated that we primarily do two things with our minds when we are awake – we alternate between taking in information or Perceiving, and evaluating that information or Judging. Jung named two psychological processes or ‘functions’ for Perceiving – Sensing (S) and Intuition (N) and two processes for Judging – Thinking (T) and Feeling (F). We focus our Perception and our Judgment toward the world outside of us as we Extravert (e) and the world inside of us as we Introvert (i).

We use all four psychological functions in Extraverted and Introverted ways, yielding eight Mental Functions, or perspectives, known as the ‘Function-Attitudes’ (or Mental Processes or Cognitive Processes). We exchange our mental energy all day long between Perceiving and Judging, in our outside world and inside world, as we engage the eight Mental Functions of Type.

Psychological Type theory was popularized through the well-known Myers-Briggs Type Indicator. Isabel Myers, the creator of the MBTI Assessment, enhanced Jung’s theory with her 16 Type Codes that point to underlying complex information about how we theoretically use and develop the mental processes. MBTI Type opens the door to the core of Jungian Psychological Type and the dynamic pattern of how our minds move from function to function.

Type Dynamics and the Hierarchy of Functions

Jung’s four functions of Sensing, Intuition, Thinking and Feeling, when used in the outside (e) and inside (i) worlds, take on very different forms. When a function is used in the outside world, it is objective and carries with it the fast and active energy of Extraversion. When a function is used in the inner world, it is subjective, known only to the person engaging the function and appears to carry with it slower, more deliberate, energy.

According to our Type, we engage all eight functions in our inner and outer worlds, with different levels of comfort and ease. Our Type has built-in mechanisms to help us maintain balance between the inner and outer worlds, and Perceiving and Judging.

Functions in the Dominant or leading role, possess unique gifts, blind spots, and contributions that manifest in the workplace. The Dominant Functions take on different perspectives and seek information around a “central question.”  The unique properties of each of the Dominant Functions are highlighted in our Eight Jungian Function Image Metaphor Card Sets.

[ESTP / ESFP] Extraverted Sensing (Se) – Perception (data gathering) in the outer world that gathers sensory data in the present to direct the next move. Enticed by the most stimulating experience. Adept at quick action and attuned to trouble shooting in the moment.  Asks: What is coming my way and what action will I take?

[ISTJ / ISFJ] Introverted Sensing (Si) – Perception (data gathering) in the inner world that gathers data through reviewing or “re-living” relevant  sensory experiences. Stores pertinant historical facts in an internal data bank. Uses experience to clarify and make distinctions between the past and current situation. Attuned to best practices.  Asks: How are my stored experiences informing me about the present?

[ENTP / ENFP] Extraverted Intuition (Ne) – Perception (data gathering) in the outer world that gathers information by noticing and making connections between seemingly disparate data. Searches for the new and possible by actively brainstorming ideas and options to catalyze forward movement. Builds on evolving ideas which continually mushroom into something new.  Asks: What patterns are emerging and how do they mean for the future?

[INTJ / INFJ] Introverted Intuition (Ni) – Perception (data gathering) in the inner subjective world that gathers information by way of the unconscious. Sees the bigger picture through the “mind’s eye”. Connects and synthesizes information from diverse sources to form a future vision. Focus is on the essence of things and potential for transformation.  Asks: How are my insights shifting my perspective of what’s to come?

[ESTJ / ENTJ] Extraverted Thinking (Te) – Judgment (decision making) in the outer world that seeks to evaluate information by organizing and structuring tasks to meet a goal. Builds plans that require segmenting resources and time-frames to achieve desired outcomes. Focus is on getting things done in the most expeditious manner. Asks: What is the most clear-cut and efficient course of action?

[ISTP / INTP] Introverted Thinking (Ti) – Judgment (decision making) in the inner subjective world that searches for answers by categorizing and analyzing a situation based on subjective frameworks. Works from underlying principles to see if something fits into the relevant mental model. Focus is on finding elegant and accurate solutions.  Asks: What is the most precise and refined answer?

[ESFJ / ENFJ] Extraverted Feeling (Fe) – Judgment (decision making) in the outer world that evaluates situations by pinpointing the values of a group to facilitate and accommodate others. Places importance on concordance in relationships; searches for commonalities between people to bridge gaps in understanding.  Asks: What is the most harmonious decision?

[ISFP / INFP] Introverted Feeling (Fi) – Judgment (decision making) in the inner subjective world that seeks to decide based on a set of deeply held internal values. Focus is on decisions that maintain the integrity and alignment between inner values and the outer situation or environment. Asks: Will this decision sustain who I am?

Jung hypothesized that if we are supported in our Type by our environment – our family of origin, context, surroundings, jobs, etc. we will naturally progress from comfort with our Dominant and Auxiliary through the first stages of life, to developing our less preferred functions, the as we age.

The Dominant Function

The Dominant (or leading) Function is the first Mental Function in the Type Hierarchy of each of the 16 Types; it appears as one of two middle letters of our 4- letter Type Code. The Dominant is the most conscious of our Functions and is theoretically the Function we use and have developed the most. Like the captain of a ship, or the driver of a car, the Dominant Function leads the personality, giving it direction. The Dominant Function defines the manner in which we most comfortably adapt to the world. We rely on our Dominant the most to guide us through life’s situations, especially during the first half of life.

The Auxiliary Function

The second function in the type code hierarchy is the Auxiliary (or supporting) Function. It is represented by the middle letter in the Type Code that is opposite the Dominant. The Auxiliary Function guides the Dominant Function by providing it with the opposite perspective, as if to say – look, this is what you have forgotten to consider! The Auxiliary provides balance for the Dominant in both how we process information and how we use our energy.

The Tertiary Function

The Tertiary Function is opposite the Auxiliary on the same dichotomy; it is used in either the same OR the opposite attitude of the Dominant Function. The Tertiary Function does not appear in the four letters of the MBTI® Type Code as it is one of the functions that is more unconscious and takes us more energy to use. Like the Auxiliary Function, the Tertiary helps the Dominant Function navigate in a different direction to keep us balanced.

The Fourth or Inferior Function

The Inferior Function (also known as the fourth function) is opposite the Dominant Function on the same dichotomy and is in the opposite attitude of the Dominant.

We have a harder time accessing, using and becoming comfortable with this function than we do with the other three Mental Functions in our Type Hierarchy. The Inferior Function can be the most problematic of the functions in our Type Code as it is inherently contradictory to the Dominant. The Inferior Function’s purpose is to provide us with an entirely different perspective from our Dominant. It provides us with an ability to tap into the world of the unconscious.

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