The sympathetic choice corresponds with the ideal ego
of the individual tested.
The negative choice with his original ego.
The ego dominating his original ego is called superego by Calehr,
whereas its projection is the subego in his terminology.

Subego is the revolutionary discovery of Calehr.
It is the "atma" (soul) of the individual.
"The knowledge of the atma is the highest".
Id is the projection of the ideal ego.
To understand the mechanism of this psychodynamic projection according to BEST,
it is mandatory to master the Laws of the Five Element Doctrine (U Sing) of Traditional Chinese Medicine and that of Traditional Indian Medicine (Ayurveda) related to its Yin-Yang dichotomy.

Thus, five ego structures result with the individual tested, viz.:

  1. Id (genetically fixed, however, flexible psychodynamically)
    It is prenatal and formed with birth It is the "seed" of the individual.
  2. Subego (it is the root of the individual )
    It is formed between 0-2 years of age. It is the "atma" (soul) of the individual.
  3. Original ego (it is the real ego of the individual)
    It is formed between 2-5 years of age. It is the "stem" of the individual.
  4. Ideal ego (it is the mirror image of the individual going throughout his life)
    It is formed between 5-7 years of age. It is the "branch" of the individual.
  5. Superego (it is the moralizing ego changing respectively dominating the real ego/original ego.
    Adapted to environment as a result of defense mechanism formed
    during one's individuation in his struggle throughout life according to Calehr).
    It is formed after 7 years of age usually concluded at the age of 25 and
    goes on until the present time as a psychodynamic process to be evaluated by BEST.
    It is also called the "present ego"

     

There are 90 different individual Types in term of BEST,
based upon positive (sympathetic) and negative (antipathetic) choices called Subtypes.

Reference: 
H. Calehr: lnstruction Manual of Basic Emotional Structuring Test
(second revised and enlarged edition, 
Scientific Publication Series of the International Acupuncture, 
Psychosomatic Center
Bandung, Java, Indonesia 1989)
see pages 33-55.