Jung's Theory of Psychological Types and the MBTI® Instrument

This excerpt is taken from Chapter 1 of the 1985 MBTI® Manual: A Guide to the Development and Use of the Myers-Briggs Type Indicator™. It was based on the first version of the Manual by Isabel Myers and written by Mary H. McCaulley, Ph.D. and founding President of CAPT. The Manual was published by CPP, Inc. The 3rd Edition of the Manual was published by CPP, Inc. in 1998.

"The purpose of the Myers-Briggs Type Indicator™ is to make the theory of psychological types described by C. G. Jung (1921/1971) understandable and useful in people's lives. The essence of the theory is that much seemingly random variation in behavior is actually quite orderly and consistent, being due to basic differences in the way individuals prefer to use their perception and judgment."

Perception involves all the ways of becoming aware of things, people, happenings, or ideas. Judgment involves all the ways of coming to conclusions about what has been perceived. If people differ systematically in what they perceive and in how they reach conclusions, then it is only reasonable for them to differ correspondingly in their interests, reactions, values, motivations, and skills.

The MBTI™ instrument is based on Jung's ideas about perception and judgment, and the attitudes in which these are used in different types of people. The aim of the MBTI™ instrument is to identify, from self self-report of easily recognized reactions, the basic preferences of people in regard to perception and judgment, so that the effects of each preference, singly and in combination, can be established by research and put into practical use…


The MBTI® instrument differs from many other personality instruments in these ways:

	It is designed to implement a theory; therefore the theory must be understood to understand the MBTI® instrument.
	The theory postulates dichotomies; therefore some of the psychometric properties are unusual.
	Based on the theory, there are specific dynamic relationships between the scales, which lead to the descriptions and characteristics of sixteen "types."

The MBTI™ instrument contains four separate indices. Each index reflects one of four basic preferences which, under Jung's theory, direct the use of perception and judgment. The preferences affect not only what people attend to in any given situation, but also how they draw conclusions about what they perceive.

Extraversion-Introversion (EI): The EI index is designed to reflect whether a person is an extravert or an introvert in the sense intended by Jung. Jung regarded extraversion and introversion as "mutually complementary" attitudes whose differences "generate the tension that both the individual and society need for the maintenance of life." Extraverts are oriented primarily toward the outer world; thus they tend to focus their perception and judgment on people and objects. Introverts are oriented primarily toward the inner world; thus they tend to focus their perception and judgment upon concepts and ideas.

Sensing-Intuition (SN): The SN index is designed to reflect a person's preference between two opposite ways of perceiving; one may rely primarily upon the process of sensing (S), which reports observable facts or happenings through one or more of the five senses; or one may rely upon the less obvious process of intuition (N), which reports meanings, relationships and/or possibilities that have been worked out beyond the reach of the conscious mind.

Thinking-Feeling (TF): The TF index is designed to reflect a person's preference between two contrasting ways of judgment. A person may rely primarily through thinking (T) to decide impersonally on the basis of logical consequences, or a person may rely primarily on feelings (F) to decide primarily on the basis of personal or social values.

Judgment-Perception (JP): The JP index is designed to describe the process a person uses primarily in dealing with the outer world, that is, with the extraverted part of life. A person who prefers judgment (J) has reported a preference for using a judgment process (either thinking or feeling) for dealing with the outer world. A person who prefers perception (P) has reported a preference for using a perceptive process (either S or N) for dealing with the outer world.