## Background

Myers Briggs codes are 4-letter combinations that categorize the 16 personality types.  Each of these codes can be translated into a corresponding "process" or sequence of "cognitive functions."  There are 4 functions and they are divided into two categories:

(J)  Judging Functions:  T = thinking  ;  F = feeling
(P) Perceiving Functions:  N = intuition; S = sensing

The "aspect" of a particular function indicates whether it is extraverted (e) or intraverted (i).  So, for example "Fe" would represent "extraverted feeling."  With 2 aspects and 4 functions, this means there are 8 total possible combinations of function and aspect:

Te, Ti, Fe, Fi, Ne, Ni, Se, Si

According to MBTI theory, everyone uses all 8 of these functions.  However, the personality type determines the *order* in which they are used.  Here is a step-by-step process for doing this.

## Step-by-step procedure

Begin with the 4-letter MBTI "type" code.  The possible letters in this code are as follows:

letter 1:  I or E
letter 2:  N or S
letter 3:  T or F
letter 4:  J or P

1.  Letter 1 fully determines the sequence of aspects, which alternate.

letter 1 = I (introverted):  aspect sequence is [i e i e e i e i]
letter 1 = E (extraverted):  spect sequence is [e i e i i e i e]

2.  If letter 4 is P:
letter 2 is the first extraverted function
letter 3 is the first intraverted function.

3.  If letter 4 is J:
letter 3 is the first extraverted function
letter 2 is the first intraverted function

4.  Steps 2 and 3 together define the first 2 functions.  The third function is the the dual opposite of the second.  The fourth function will be the dual opposite of the first.

5.  Functions 5 through 8 are the same sequence as functions 1 through 4.

## Example:  INTJ

Step 1.  letter 1 is I, so the aspects are [i e i e e i e i]

Step 2.  letter 4 is J.  So, the first e function is T and the first i function is N.  Based on the sequence in Step 1 we know that the first i function (N) comes before the first e function (T), so the first two pairs in the function sequence are:  N, T, ...

Step 3.  does not apply.

Step 4.  the third function is F, the dual opposite of T;  and the fourth function is S, the dual opposite of N.  The first 4 functions are thus:  N, T, F, S, ...

Step 5.  the remaining 4 "shadow functions" are the same sequence repeated.

So the full sequence of functions is [N, T, F, S, N, T, F, S].  Combining these with the aspects in step 1, we have: [Ni, Te, Fi, Se, Ne, Ti, Fe, Si]

## Example:  ESTJ

Step 1.  letter 1 is E, so the aspects are [e i e i i e i e]

Step 2.  letter 4 is J.  So, the first e function is T and the first i function is S.  Based on the sequence in Step 1 we know that the first e function (T) comes before the first i function (S), so the first two pairs in the function sequence are:  T, S, ...

Step 3.  does not apply.

Step 4.  the third function is N, the dual opposite of S;  and the fourth function is F, the dual opposite of T.  The first 4 functions are thus:  T, S, N, F, ...

Step 5.  the remaining 4 "shadow functions" are the same sequence repeated.

So the full sequence of functions is [T, S, N, F, T, S, N, F].  Combining these with the aspects in step 1, we have: [Te, Si, Ne, Fi, Ti, Se, Ni, Fe]