What are the principles and applications of Type Theories?

Personality type refers to the psychological classification of different types of people. Personality types are distinguished from personality traits, which come in different levels or degrees. For example, according to type theories, there are two types of people, introverts and extraverts. According to trait theories, introversion and extraversion are part of a continuous dimension, with many people in the middle. The idea of psychological types originated in the theoretical work of Carl Jung and William Marston, whose work is reviewed in Dr. Travis Bradberry’s Self-Awareness. Jung’s seminal 1921 book on the subject is available in English as Psychological Types.

Building on the writings and observations of Jung, during World War II, Isabel Briggs Myers and her mother, Katharine C. Briggs, delineated personality types by constructing the Myers-Briggs Type Indicator. This model was later used by David Keirsey with a different understanding from Jung, Briggs and Myers. In the former Soviet Union, Lithuanian Aušra Augustinavičiūtė independently derived a model of personality type from Jung’s called Socionics.

The model is an older and more theoretical approach to personality, accepting extraversion and introversion as basic psychological orientations in connection with two pairs of psychological functions:

• Perceiving functions: sensing and intuition (trust in concrete, sensory-oriented facts vs. trust in abstract concepts and imagined possibilities)
• Judging functions: thinking and feeling (basing decisions primarily on logic vs. considering the effect on people).

Briggs and Myers also added another personality dimension to their type indicator to measure whether a person prefers to use a judging or perceiving function when interacting with the external world. Therefore they included questions designed to indicate whether someone wishes to come to conclusions (judgment) or to keep options open (perception).

This personality typology has some aspects of a trait theory: it explains people’s behaviour in terms of opposite fixed characteristics. In these more traditional models, the sensing/intuition preference is considered the most basic, dividing people into “N” (intuitive) or “S” (sensing) personality types. An “N” is further assumed to be guided either by thinking or feeling, and divided into the “NT” (scientist, engineer) or “NF” (author, humanitarian) temperament. An “S”, by contrast, is assumed to be guided more by the judgment/perception axis, and thus divided into the “SJ” (guardian, traditionalist) or “SP” (performer, artisan) temperament. These four are considered basic, with the other two factors in each case (including always extraversion/introversion) less important. Critics of this traditional view have observed that the types can be quite strongly stereotyped by professions (although neither Myers nor Keirsey engaged in such stereotyping in their type descriptions), and thus may arise more from the need to categorize people for purposes of guiding their career choice. This among other objections led to the emergence of the five-factor view, which is less concerned with behavior under work conditions and more concerned with behavior in personal and emotional circumstances. (It should be noted, however, that the MBTI is not designed to measure the “work self”, but rather what Myers and McCaulley called the “shoes-off self.”) Some critics have argued for more or fewer dimensions while others have proposed entirely different theories (often assuming different definitions of “personality”).

Type A and Type B personality theory: During the 1950s, Meyer Friedman and his co-workers defined what they called Type A and Type B behavior patterns. They theorized that intense, hard-driving Type A personalities had a higher risk of coronary disease because they are “stress junkies.” Type B people, on the other hand, tended to be relaxed, less competitive, and lower in risk. There was also a Type AB mixed profile.