The Myers-Briggs Type Indicator (MBTI) is a personality indicator based on the work of Carl Jung. The MBTI is based on Carl Jung's theory of individuation (understanding of the self) and was developed by Katherine Briggs and her daughter Isabel Briggs Myers. The MBTI attempts to pick up on patterns of behaviour that reflect individual differences in the way people perceive information and make decisions.

The MBTI measures four scales with 8 preferences.

Introversion <----> Extraversion
Sensing <----> iNtuition
Thinking <----> Feeling
Judging <----> Perceiving

A good summary of the 8 preferences (from follows:

The Eight Preferences
(E)xtraversion: Focus on outer world of people, many friends with brief contact, Talk more than listen, Approachable, keep up with social happenings.
(I)ntroversion: Focus on inner world of ideas. Few friends with longer contact, Good listeners, reserved, reflective, private.
(S)ensing: Focus on the present, like tangible results, facts and figures, Sequential--Front to back, literal, down to earth, specific answers, routines.
i(N)tuition: Focus on the future or past, patterns & possibilities, ideas and theories, head in the clouds, like general answers, fantasies and daydreaming.
(T)hinking: Decisions based on logic and objective analysis, remember numbers & figures better than names & faces, prefer truth over agreement.
(F)eeling: Decisions based on personal feelings and values, think with the heart, compassionate, puts self in others' shoes, prefer harmony over truth.
(J)udging: Likes to-do lists and schedules, organized, neat, do what you're supposed to do, deadlines, order, get things done, work first, always on time.
(P)ercieving: Flexible, spontaneous, adaptable, doesn't plan, like the unknown, easily distracted, wait till last minute, turns work into play, keep options open.

The eight preferences are combined to define 16 distinct personality types, as follows (source:

Supervisor ESTJ Inspector ISTJ
Provider ESFJ Protector ISFJ

Promoter ESTP Crafter ISTP
Performer ESFP Composer ISFP

Teacher ENFJ Counselor INFJ
Champion ENFP Healer INFP

Fieldmarshal ENTJ Mastermind INTJ
Inventor ENTP Architect INTP

Unfortunately many people erroneously interpret their type by reading across the four letters and relating the significance of each letter independently. The real way of examining the four letters is to identify your dominant and auxillary functions. Again from

Your functions are your 2nd (Sensing/iNtuition) and 3rd (Thinking/Feeling) letters of your type.

Your Dominant and Axuillary functions are always your preferences in the S/N and T/F letters. Your 3rd and 4th place functions are always your non-prefernces in the S/N and T/F letters.

Your 1st function (2nd letter) is your perceptive / data collecting function.

Your 2nd function (3rd letter) is your judging / processing function.

The last letter (Judging/Perceiving--J/P) determines whether your 1st function (perceptive) or your 2nd function (judging) is your extraverted function: J=Thinking/Feeling (T/F), P=Sensing/iNtuition (S/N)

The first letter (Extroversion/Introversion--E/I) determines whether your xtraverted function is Dominant or Auxiliary. Extravert = Extraverted function is dominant; Introverted function is auxillary. Introvert = Introverted function is dominant; Extraverted function is auxillary.

Confused? You can still use the MBTI types as a mental plaything See also the The Keirsey Temperament Sorter which has an online test site at and is based on the Jungian Types