ENFJ, INFP, ISTJ, ISFP - many know these are the short-hand designations for the 16 Personality Types popularized by Isabel Myers and her successors fascinated by the theory of personality originally postulated by psychologist Carl Jung. But less well known is that there is an order and organization to these letters code.
The middle two letters of the Personality Type Code refer to what Isabel Myers and Psychologist Carl Jung called the "mental functions" (Sensing, Intuition, Thinking, and Feeling). These functions or mental processes are divided into two categories: perceiving N/S and judging T/F. The second letter of the personality type code represents the preferred means of perceiving of that personality type. The third letter represents the preferred means of judging. Although the four letter type code only shows two of these functions or processes, everyone has and uses all four of them. Examples. Those who prefer Intuition (second letter is N) will use or rely upon their Sensing nature in some specialized way - complimenting rather than conflicting with their more preferred Intuition. Those whose preference is Thinking (third letter is T) will value and use its opposite, Feeling, in certain ways and sometimes will let this function be their guide even though normally the person favors Thinking.
Two Kinds of Functions
Sensing (S) and Intuition (N) are considered Perceiving Functions. They are two contrasting ways of taking in information. Thinking (T) and Feeling (F) are considered Judging Functions. They are two contrasting ways of making decisions.
Perceiving and Judging are essential components to all cognitive activity. There can be no Judging without prior Perception; and no Perception without some form of Judging inevitably following. They are hand-in-glove processes. Whatever is a person's most favored Perceiving process combined with whatever is his/her most favored Judging process is at the core of personality and is a major influence in the overall constellation of personality development.
The Dominant Function or Mental Process
One of these two most favored processes takes the lead and is termed the Dominant Function. The other works in a supportive fashion to the dominant and is termed the Auxiliary Function. So while two personality types may share the same two middle letters in the code (For example ESTP and ESTJ), their Dominant and Auxiliary functions can be reversed . . . and thus one reason why there can be marked differences in their respective personality makeup. In the examples, ESTP is Sensing Dominant supported by Thinking Auxiliary; whereas ESTJ is Thinking Dominant supported by Auxiliary Sensing. ESTP prefers the Perceiving half of the ST Perceiving-Judging pair; whereas ESTJ prefers the Judging half of the ST Perceiving-Judging pair.
Hierarchy of Mental Functions
Each of the 16 personality types has a characteristic pattern in the alignment of the four mental functions. This pattern is referred to as a "hierarchy" because they typically differ in the degree of influence on the personality and the degree they are consciously experienced. As indicated above, the most important or influential function is termed the "Dominant" function (#1) and the second most important is termed the "Auxiliary" (#2). The third in the hierarchy is called the "Tertiary" (#3) and is the polar opposite of whatever function is the Auxiliary. The Fourth in order Jung termed the "Inferior" function (#4). It is the mental process with the least conscious awareness and typically the least developed of the four functions. It is the polar opposite of whatever is the Dominant. So if INtuition is Dominant, its opposite - Sensing - is the Inferior or Fourth. If Feeling is Dominant, then its opposite - Thinking - is Inferior or Fourth.
The rationale for the opposite relationship of the Dominant and the Inferior (fourth function) has to do with energy and the natural polarity of the mental functions. For example, a person with dominant Intuition will direct his/her primary energy to this function - which happens to be in the exact opposite direction of Sensing. It is like trying to go North and South at the same time. It is much easier to couple that dominant with either the Auxiliary or Tertiary because these are not polar opposites to the main direction. They are like East and West on the compass. So navigating NW or NE is a natural direction of movement - but North-South is not.
Some students of Personality Type, myself included, are uncomfortable with using Jung's term for the Fourth function: "Inferior." Bear in mind Jung was writing in the 1920's and his works had to be translated from German to English. I bring this up to caution the reader against jumping to conclusions on this Dominant-Inferior pairing. To wit, although a person's dominant function might be Feeling and therefore their inferior function is Thinking, do not presume that their "thinking" is inferior, i.e. defective!! For reasons to be explained later, there is often a built-in growth dynamic to consciously develop whatever is opposite one's dominant mental function.
Attitude is Also Important - the first letter in the code of Personality Types
Here's another Jungian term that carries a somewhat different meaning in the 2006 English speaking world. We don't mean your world view or the rosyness of your outlook. It isn't like "Lose the attitude, Dude!"
Just as the oppositeness of the mental functions can be comprehended by using the analogy of the four points of a compass (N/S, E/W), Jung's Attitudes are a navigational concept. It has to do with orientation. Here again, we encounter opposites. Jung coined the terms Extraversion and Introversion to refer to the two polar opposite directions of psychic attention and energy. He found that whatever was a person's dominant mental function was directed to either the external world (E) or the internal world (I). This preference in attitude of the dominant function is a major distinguishing feature in personality type patterns. So while ISTP and ESTJ both have Thinking as their dominant function, the former prefers to direct it inward whereas the latter directs it outward. The result is quite different styles of personality.
Another kind of Attitude - the fourth letter of the code of Personality Types
Had Myers and Briggs not inferred a second type of Attitude from Jung's work, there might have only been three letters to their type code. We would have seen INT, INF, ITS, EST, ETN, etc. But their independent study of people and people differences, with Jung's typology as an important tool, lead them to create the polar preferences of Judging and Perceiving - which became the fourth letter in their Personality Type Code system. This attitude is the Outer World Orientation and is related to the kind of mental function one turns to the outside world.
In the Myers-Briggs four letter code, J means that our Judging Function (either Thinking or Feeling) is turned to the outside world and P means that our Perceiving Function (either Sensing or Intuition) is oriented to the outside world. So ISFJ indicates Judging Function "F" is turned to the outside world; INTJ indicates Judging Function "T" is turned to the outside world. ENFP indicates this type turns their Perceiving Function "N' to the outside world; ESTP indicates their Perceiving Function "S" is oriented externally.
For Extraverted Types, their dominant mental function determines their Outer World Orientation. Note in the above table that the types with Extraverted Intuition or Extraverted Sensing have P (for their Perceiving Function) as their last MBTI type code letter. Conversely those with Extraverted Thinking or Feeling have J (for their Judging Function) as their fourth letter. With Extraverts, what you see is what you get; they extravert their most favored mental process, their Dominant mental function.
For Introverted Types, it is an opposite flow of psychic energy. They direct their most favored mental function inward and therefore more readily show to the outside world their supportive or auxiliary function. So the four Introverted Types (I_ _ Js) whose dominant preference is a Perceiving function (which is introverted), orient their Auxiliary preference - which is Judging - to the outside world. Conversely the four Introverted Types (I_ _ Ps) whose dominant preference is a Judging function (which is introverted), orient their Auxiliary preference - which is Perceiving - to the outside world. Ergo, the 4 "I_ _J" Introverted Types are in actuality more strongly governed by their "P" (Perceiving Function) inside and the 4 "I_ _P" Introverted Types are more strongly governed by their "J" (Judging Function) inside.
The Yin Yang of J and P
In general people with a Perceiving Outer World Orientation (last letter P) have a go-with-the-flow orientation, taking things as they come, keeping their options open, and adapting to whatever comes up. Their opposite, those with a Judging Outer World Orientation, like to plan their work and work their plan. They order and anticipate what is going on in the outside world. Think about people you know; I suspect you can readily find several who fit the mold of J or P types. This characteristic is one of the four primary ways people differentiate from one another.
Now understand that everybody is both a J and a P. If they are J on the outside, they are a P on the inside. If they are P on the outside, they are J on the inside. Because they tend to hide their dominant function, Introverted Types best illustrate the befuddlement that can occur due to this Yin Yang duality: what you see is not necessarily what you get. But even extraverts can cross you up on occasion. ESTP types are among the most adaptable, go-with-the-flow, in the moment types. Yet in some situations they can be inflexible, closed minded, and set in their ways when their inner Thinking Judgment has taken over.
Another element of Yin and Yang is the natural opposite orientation of all four mental processes. If a person clearly extraverts Thinking, this is a clue that Feeling is introverted. If what you readily see is Intuition freely used in the outside world, this is a clue that Sensing is introverted. People who clearly make their stated judgments based on Feeling, typically use Thinking in their inner world. ISFJ types who are typically quite courteous, sensitive to the values & feelings of others, and present a pleasant demeanor can actually be quite firm-minded, logical thinkers on the inside. INFP types whose inner Feeling values dominate how they form judgments can be quite formidable logical debaters, sometimes to such an extent that their extraverted Thinking disguises the depth of their inner Feeling.
The Yin Yang of E and I
Picture again the Compass of the Functions. Recall that the mind cannot go both North and South simultaneously, nor East and West simultaneously. Yet if you add the dimension of the two energy consciousness realms - introversion and extraversion, it clarifies what are truly opposite. For example, the polar opposites of Thinking and Feeling would create strong competition with one another in the same energy consciousness realm; one must dominate. But it seems, this competition isn't an issue if they are in different realms: one extraverted and the other introverted. For example, a person with strong inner Feeling and well reasoned outer Thinking is a workable personality pattern; the two opposing mental functions can compliment one another. Likewise with Sensing and Intuition Functions. For example, the open, exploratory, go-with-the-flow thrust of extraverted Intuition is nicely counterbalanced by the ability to recall important details and be grounded by introverted Sensing.
As people grow and mature, this growth of opposites in the opposite realms of energy consciousness can be a natural pattern of development. People with dominant introverted Intuition may feel an urge to develop their extraverted Sensing; people with dominant extraverted Feeling may feel an urge to develop their introverted Thinking. It becomes a way of achieving some balance and expanded growth without compromising what is the person's anchor - their dominant mental function.
While the Hierarchy of Functions mentioned early in this article suggests this hierarchy forms the requisite growth or development pattern for a type, environment may alter that pattern. Occupational demands may require that a person develop skills and or a sensitivity to a mental function out of its natural order. A Feeling preference person who happens to choose accounting for a profession will certainly experience a necessity to develop and use the Thinking function. Also there are certain individuals who are simply atypical of their type (as are ambidextrous and left handed people whose brain organization is known to be atypical from what is considered the normal hemispherical organization).
This interaction of nurture with nature or the existence of atypical personality type continues to incite debate and discussion among students of Personality Type about the nature of the hierarchy of functions and whether the notion of hierarchy is even useful. What is presented here is a model of the psyche that I've found has explanatory value in my interactions with people I know and have worked with from all 16 type categories and from a variety of backgrounds.
Further Explanation of Perceiving Functions N/S
Lets divide objects into two components: its physical manifestation and its immaterial essence of protoform. The physical component is the object's physical properties: color, shape, texture, etc., while the immaterial component denotes its meaning. Naturally, both exist within our experience, but brain's map of reality prioritizes one of the components over the other, thus making a person be a sensing or an intuitive type.
For a sensing type, structure of reality is primarily perceived as made-up of the physical aspect. For this reason, the S-type is drawn to tangible, concrete, physical manifestation of surrounding worlds. The sensing types are also aware of the intuitive component, but only weakly, as within S-type's reality structure the physical component is strongly delineated.
The mind of N-type is sensitive to the intangible, immaterial components of reality. Since reality is constantly flowing and changing over time, all static objects are associated with a component of metamorphosis, change, motion and process. Intuitive types are acutely aware of these recombinatory, permutative processes associated with an object or event, while the tangible, physical forms imprint only weakly in this person's matrix of reality.