Jungian cognitive functions

In some forms of psychometrics, particularly those related to the Myers-Briggs Type Indicator, the cognitive functions (sometimes known as mental functions) are defined as different ways of experiencing and thinking about the world. They are defined as "thinking", "feeling", "sensing" and "intuition".

History of Jungian cognitive function models
The model in which these four cognitive functions combine in different ways to form different people's personalities was initially conceived by Carl Jung in his pioneering work Psychological Types (1921, ISBN 0-691-09770-4). Jung also posited that the functions formed a hierarchy within a person's personality -- the most important function is referred to as the "dominant", with the remaining three filling the progressively less important roles of "auxiliary", "tertiary" and "inferior". In addition, each mental function is seen as either introverted or extraverted (known as attitudes). This idea is interpreted in terms of whether the person finds it more rewarding when using the function in question to have an outward focus on people and things (extraversion) or an inward focus on thoughts and ideas (introversion). These models do not claim that people are only capable of applying the function in question in that attitude, but rather that operating in the opposite attitude requires the expenditure of "energy" (or rather, emotional resources, enthusiasm, and so on) whilst operating in the person's natural attitude replenishes that same energy.

Isabel Myers, an early pioneer of psychometric testing whose ideas remain controversial within psychology, formalised these ideas and proposed that the mixture of types in an individual's personality could be measured through responses to a personality test she devised along with her mother, Katharine Cook Briggs, the Myers-Briggs Type Indicator. In this model, four "dichotomies" are defined, each labelled by two letters (one for each of the opposites in question), as shown by the emboldened letters in the table. Individuals' personalities fall into sixteen different categories depending on which side of each dichotomy they belong to, labelled by the four applicable letters (for example, an "ESFP" type is someone whose preferred way of thinking is extraverted, sensing, feeling and perceiving).

Controversy over attitudes
Myers interpreted Jung as saying that the auxiliary, tertiary, and inferior functions are always in the opposite attitude of the dominant. In support of Myers' (and/or Briggs') interpretation, in one sentence Jung seems to state that the three inferior functions of an (extreme) extravert are introverted. The "most differentiated function is always employed in an extraverted way, whereas the inferior functions are introverted" (Jung, [1921] 1971:par. 575).

Many, however, have found Jung's writing to be ambiguous, and those who study and follow Jung's theories (Jungians) are typically adamant that Myers is incorrect. Jungians interpret Jung as explicitly stating that the tertiary function is actually in the same attitude as the dominant, providing balance. More recently, typologists such as John Beebe and Linda Berens have introduced theoretical systems in which all people possess eight functions -- equivalent to the four functions as defined by Jung and Myers but in each of the two possible attitudes -- with the four in the opposite attitude to that measured known as the "shadow functions," residing largely in the unconscious.

There is controversy even within the Center for Applications of Psychological Type (CAPT), co-founded by Myers, regarding the attitude of the tertiary relative to the dominant. "The MBTI Qualifying Program," a binder given out during official training, puts the tertiary in the opposite attitude to the dominant on page 13; however, "The Manual," which gives official instructions on how to use the test, has the tertiary in the same attitude on page 31. Dr. Charles Martin, ex-Vice President of research at CAPT, writes the following on page 22 of the binder, "In what attitude is the tertiary? Isabel Myers read Jung to say that the auxiliary, tertiary, and inferior are all in the same attitude and opposite the dominant. Others (Harold Grant) read: tertiary is in the same attitude as the dominant."

Different models
The tables below give different thinkers' ideas about differing personality types in terms of "cognitive functions".

The cognitive functions according to Carl Jung
Carl Jung developed the theory of cognitive processes in his work "Psychological Types". He used the terms dominant, auxiliary, and inferior.

There is a difference between Jung and the MBTI regarding the designation of "inferior" function. While the MBTI clearly designates only the fourth function as the inferior, Jung uses a more flexible definition. "As a consequence of this one-sided development, one or more functions are necessarily retarded. These functions may properly be called inferior ..." (Jung, [1921] 1971:Def. INFERIOR FUNCTION par. 763).

The cognitive functions according to Isabel Myers
Isabel Myers created the original type table. In her table, diametrically opposite personality types (that is, those with no traits in common among the dichotomies) are separated by one block along diagonals.

The cognitive functions according to John Beebe
Though John Beebe has not published a type table, the format that Isabel Myers devised can also be applied to his theory. Beebe describes the different cognitive functions' role in the overall personality in terms of various mythic archetypes. Just as in Myers's table, personality types whose primary four functions are completely opposite are separated by one block along diagonals. The same does not apply to the four "shadow" functions, however.

The cognitive functions according to Linda V. Berens
The layout of Berens' type table is unique, and her terminology differs from that of Beebe; however, the ordering of cognitive processes in her and Beebe's models are the same.

The cognitive functions according to Lenore Thomson
Lenore Thomson offers yet another model of the cognitive functions. In her book, Personality Type: An Owners Manual, Lenore advances a hypothesis of a modular relationship of the cognitive functions paralleling left-right brain lateralization. In this approach the J-type functions are in the left-brain and the P-type functions in the right brain. Likewise, the extraverted functions are in the front of the brain, while the introverted functions are in the back of the brain. The order of the cognitive functions are then determined not by an archetypal hierarchy (as supposed by Beebe) but by an innate brain lateralization preference.