Basic Definitions and Concepts

Personality Type: a four letter shorthand used to designate the sixteen possible cognitive function patterns


Cognitive Process: one of the four distinct mental faculties

Thinking (T): use of things / logical implications
Feeling (F): meaning of things / impact on people
Sensing (S): experiences
iNtuition (N): concepts

Orientation: the direction or “world” of focus

Extraverted (e): focused on the outer, objective, actual world
Introverted (i): focused on the inner, subjective, ideal world

Cognitive Function: one of the eight building blocks of personality, consisting of one introverted and one extraverted orientation of each of the four cognitive processes

Fe: extraverted feeling / Fi: introverted feeling
Te: extraverted thinking / Ti: introverted thinking
Ne: extraverted intuition / Ni: introverted intuition
Se: extraverted sensing / Si: introverted sensing

Function Stack: the order in which the eight cognitive functions are given preference within a personality

Function Position: the role each of the 8 functions serves within a personality, according to it’s position within the function stack

1 2 3 4 5 6 7 8
Conscious Processes Unconscious / Shadow Processes
Dominant (Dom)
Auxiliary (Aux)
Critical Parent


Activity: the kind of actions a function performs, either perceiving or judging

Perceiving (P): gathering information, exploring, experimenting, processing, responding
Judging (J): making decisions, planning, acting, closure

Activity Rhythm: the order of preference given to perceiving and judging functions in either the conscious or unconscious group within a type, always following one of two patterns:

PJJP : Perceiving – Judging – Judging – Perceiving
JPPJ : Judging – Perceiving – Perceiving – Judging

Default (shorthand -def): the attribute within any category of attributes that a function stack gives preference to, regardless of whether the first function to have an attribute in the given category is in the first or second position. Not to be confused with the term dominant which always refers to the attributes of the function in the first position.

For example: in an ISFP stack (Fi Se Ni Te) the dominant process would be feeling and the default judging process would be feeling, but the default perceiving process would be sensing.

For further explanation of this distinction, please see the article Dominant vs. Default Attributes.

Activity Axis (plural = Axes): a pair of judging or pair of perceiving functions that always occur together within a type:

Polarity: the preferred orientation of an activity axis within a function stack, either towards the introverted or extraverted end

Extraverted Polarity Introverted Polarity
Judging Axis Je–Ji Ji–Je
Perceiving Axis Pe–Pi Pi–Pe

Within a personality type’s function stack, the judging and perceiving axes are always inverted in relation to each other, so that if the judging axis has an extraverted polarity, the perceiving axis has an introverted polarity, and vice versa.

This results in there being only two possible polarity combinations when the two axes are taken together as part of a stack.

Name Full Notation Shorthand Notation
Possibility 1 Convex Je–Ji / Pi–Pe Je / Pi
Possibility 2 Concave Ji–Je / Pe–Pi Ji / Pe

Concave Polarity: Extraverted concave activities act like a concave lens and have a diverging effect. Introverted concave activities act like a concave mirror and have a converging effect.

Ji and Pe are the concave ends of their respective activity axes. Both of the following stack patterns are concave, meaning their four functions follow a concave – concave – convex – convex pattern.

  • Pe Ji Je Pi
  • Ji Pe Pi Je

Convex Polarity: Extraverted convex activities act like a convex lens and have a converging effect. Introverted convex activities act like a convex mirror and have a diverging effect.

Je and Pi are the convex ends of their respective activity axes. Both of the following stack patterns are convex, meaning their four functions follow a convex – convex – concave – concave pattern.

  • Je Pi Pe Ji
  • Pi Je Ji Pe

Interaction Dynamic: when two types come together,  how the similarities and differences in their cognitive functions affect each other. Each type experiences each interaction dynamic with one other type.

Quadra: a group of four personality types that share the four conscious cognitive functions / the conscious judging and perceiving axes
SF / NT Fe–Ti Fi–Te NF / ST
Ne–Sie-NF / i-STe-NT / i-SF Ne–Si
ESFJ - Fe Si Ne Ti ENTP - Ne Ti Fe Si ESTJ - Te Si Ne Fi ENFP - Ne Fi Te Si
ISFJ - Si Fe Ti Ne INTP - Ti Ne Si Fe ISTJ - Si Te Fi Ne INFP - Fi Ne Si Te
Ni–See-SF / i-NTe-ST / i-NF Ni–Se
ENFJ - Fe Ni Se Ti ESTP - Se Ti Fe Ni ENTJ - Te Ni Se Fi ESFP - Se Fi Te Ni
INFJ - Ni Fe Ti Se ISTP - Ti Se Ni Fe INTJ - Ni Te Fi Se ISFP - Fi Se Ni Te
NF / ST Fe–Ti Fi–Te SF / NT

Actualization: the degree to which a person is realizing the healthy potential of each function in its position

Loop: a personality imbalance where the first and third functions are used while suppressing the second in an unhealthy way

Grip: a personality imbalance where the fourth function becomes dominant in an unhealthy way