Here's an updated description of Model D (mk5).
Thinking and Intuition are superfluous. They correspond to the prefrontal cortex and working memory, so they are always dependent on Sensing functions. Si+ is about object recognition/patterns and scenarios/mental projections. Se+ is about an object's position in space and similarities/differences between objects. Fe+ and Fi+ are emotional responses to these sensory processes. Si+ and Se+ are detailed and specific, Si- and Se- are general.
Fi+ (Se+) // Si+ (Fe+) ..... strong functions
Fe- (Si-) // Se- (Fi-) ..... weak functions
Si+ (Fe+) // Fi+ (Se+) ..... strong functions
Se- (Fi-) // Fe- (Si-) ..... weak functions
Se+ (Fi+) // Fe+ (Si+) ..... strong functions
Si- (Fe-) // Fi- (Se-) ..... weak functions
Fe- (Si-) // Se- (Fi-) ..... strong functions
Fi+ (Se+) // Si+ (Fe+) ..... weak functions
mk4: see post 123
Primary functions: Te- Ni+ Fe- Si+ // Ne+ Ti- Se+ Fi-
Secondary functions: Ti+ Se- Fi+ Ne- // Si- Te+ Ni- Fe+
Primary functions: Ni+ Te- Si+ Fe- // Ti- Ne+ Fi- Se+
Secondary functions: Ne- Fi+ Se- Ti+ // Fe+ Ni- Te+ Si-
"Everyone’s nervous system has two sides — the sympathetic side, which triggers the “fight, fright, or flight” response, and the parasympathetic side, which is responsible for “rest and digest” mode. Think of the sympathetic side as hitting the gas pedal and the parasympathetic side as slamming on the brakes. When your sympathetic system is activated, your body gears up for action. Adrenaline is released, glucose energizes muscles, and oxygen increases. Areas of your brain that control thinking are turned off, although dopamine increases alertness in the back of your brain. But when you use the parasympathetic side, your muscles relax, energy is stored, and food is metabolized. Acetylcholine increases blood flow and alertness in the front of your brain. Of course, extroverts and introverts use both sides at different times. But which side do we introverts prefer? You’ve probably already guessed: according to Dr. Laney, the parasympathetic side, which slows us down and calms us."
This is why we need two systems of functions (like Model D); one system with a dominant "extroverted" function and another system with a dominant "introverted" function.
Extroverted behavior is a consequence of accepting "extroverted" functions and producing "introverted" functions (and vice versa). This corresponds perfectly with Keirsey's fourth ring, expressive vs. attentive:
"The fourth ring describes how people interact with their environment. Individuals who tend to act before observing are described as expressive, whereas people who tend to observe before acting are described as attentive."
EDIT 20-01-2018 ... Here are 10 important changes and clarifications:
1. There are no valued and unvalued functions. Type compatibility is based on mutual relaxation instead. SEE, ESI and ESE are compatible with ILI. (EDIT 05-03-2018)
Why are SEE and ILI duals? Because ILI is sensitive about Si+ and Fe- (especially SiFe), but he or she is insensitive about Se+ and Fi-. SEE's indirect and childlike Si+ and Fe- match ILI's Si+ and Fe-.
2. There are probably only two basic levels of strong/weak functions. So ILI's Ni+ and Te- are equally strong. But 1D, 2D, 3D and 4D could be relevant in subtypes.
3. ILI's strong functions are Ni+, Te-, Ti-, Ne+ and Ne-, Fi+, Fe+, Ni- ... stronger = more sophisticated (they process more information).
4. One needs high-dimensional sensing in order to process high-dimensional (concrete) logic. For example, Se- (weak) -> Ti+ (strong) is not possible.
5. 'Plus' / 'minus' is a consequence of the blocking of functions.
6. 'Plus' functions are about analysis. They deal with "how", "what", "who" and "where" questions. 'Minus' functions are about synthesis. They deal with "why" questions. This is yet another reason why we need 16 functions.
7. All mental functions are equally conscious, and all vital functions are equally unconscious.
8. Why are there mental and vital functions? Because two functions must process information simultaneously. You cannot observe structural differences (Ti: longer, bigger, more...) without being somewhat aware of the object (Si or Ni).
9. The vital functions correspond to Jung's "personal unconscious".
Jung: "more or less superficial layer of the unconscious." ... "they constitute the personal and private side of psychic life."
Yermak: "Some socionists suppose that the functioning of the superblock of personal life is unconscious. It is incorrect. Founders of psychoanalysis differently considered the concept of the 'unconscious'. The term 'preconscious' is appropriate to the content of processes, which take place in the superblock of personal life. In normal conditions, the preconscious processes function out of consciousness, automatically. But these processes can become conscious, if there is a need. In turn, functioning of the superblock of social life is obviously conscious."
"the contents of vital track functions is the result of individual period of psyche development, the period when we are individuals, when we are the hub of the universe, when everything rotates around us, around our interests, when we are still children and we are not interested in the society with all its demands. Socionists say: the vital track is the superblock of individual life activity. This means that vital track functions work for our individual needs and in the way that is customary and comfortable for us."
10. ILI's SiFe is not just about people and social relationships. It supports NiTe as well. ILI's intense study of certain subjects/facts is dependent on Si+ (...Fe- evaluates if it is good or bad behavior/action). The same thing applies to NeFi. This is why Model D mk3 makes sense. Te- speculates about something (i.e. induction and abduction... Te+ is about deduction). If the ILI is confident then the information is confirmed by Si+. If he (or she) isn't confident then the information goes to Ne-, which sees alternative conclusions.
Why does ILI have NeFi as a second ego? My current view is that NiTe and NeFi complement each other (see previous comments). But there is another way of looking at it. Maybe NeFi counterbalances NiTe instead. IEE is the most open and trusting type, and ILI is the most suspicious, skeptical and independent type. If ILI's NeFi is always somewhat present, then it cannot be completely ignored. This could prevent the ILI from being too single-minded, arrogant, insensitive etc.
A third alternative: NeFi is both a complement and a counterbalance.
INFJ (Ni Fe Ti Se): "With our extraverted feeling function, INFJs tend to avoid conflicts. We need our introverted thinking to remind us that pleasing others doesn’t always resolve the issue. Sometimes it’s best, to tell the truth even if it hurts the other person and ourselves (we feel the pain when someone is hurt). Our introverted thinking also allows our extraverted feeling to take a break. Always thinking in terms of the group is rather taxing on us.
INFJs also have a tough time making decisions because of this constant tug-of-war between the brain and the heart. Even though we understand logically (Ti) that some decision isn’t the best for us, we are still very concerned about the implications of our decision on other people (Fe)."
I experience Fi+ in a similar way.
LII's TiNe is counterbalanced and/or complemented by TeSi, but ILI's TiNe is counterbalanced and/or complemented by FeNi. How is that possible? I am not completely sure yet, but it is probably because ILI's TiNe is more concrete, so it doesn't need a strong TeSi.
"A second, or auxiliary, function complements the dominant function in two ways. First, the auxiliary function is always from the other pair of functions—that is, if the dominant function is a judging function, then the auxiliary function will be the preferred perceiving function; if the dominant function is a perceiving function, then the auxiliary function will be the preferred judging function. Second, the auxiliary function will tend to operate primarily in the less-preferred attitude—either Extraversion or Introversion. Thus, if the dominant function is extraverted, then the auxiliary function will be introverted; if the dominant function is introverted, then the auxiliary function will be extraverted.
So, if your dominant function is Extraverted Thinking, your auxiliary function will be either Introverted Sensing or Introverted Intuition, whichever function you prefer. If your auxiliary preference is Introverted Intuition, the information you gather is likely to emphasize internal ideas, hypotheses, and theories.
Your dominant Extraverted Thinking judgment will focus on that kind of internal information in order to create models and systems and ways to implement them in the world. Because your dominant, driving function, Extraverted Thinking, attracts you to accomplishing things in the world, implementing your ideas will be more appealing to you than the ideas themselves."
This is inaccurate. If "introverted" Intuition gathers internal information then the "extroverted" Thinking judgement must also be internal, since there is no additional information. NB It is possible to project (Ni) objects onto a scene "in the world" (see my definitions of the functions).
An LSI / ISTP mechanic compares (i.e. judges) the sizes of two objects "in the world" (they are right in front of him). This "introverted" Thinking judgement must also be "in the world".
How to Find Yourself and Your Best Match. Socionics. The Modern Approach to Psychological Types ... by Rod Novichkov and Julia Varabyova:
"Complementary (C). All Intellectual Intuitive types are Complementary to the Emotional Sensory group and vice versa. All Intellectual Sensory types are Comlementary to the Emotional Intuitive group. Relationships between these groups are best for marriage and romance. The subconscious of Intellectual Intuitive types is Emotional and Sensing. Partners in these relationships "cover each other's back". Together they cover all aspects of Informational Metabolism. They have the same type of emotionality, same type of sexuality, same type of thinking and understanding. Partners make each other comfortable and relaxed. These relationships do not contribute to personal growth. Although C1 is the best type of relationship, it's not that easy to establish. In the beginning, partners don't seem to see each other or attract to each other. It almost takes knowledge of Socionics to even enter in such relationship. Only as the time goes along, when partners engage in common activity and spend some time with each other, they start seeing each other's qualities and get attracted to each other. Once you've been in C1, you'll never want anything else. The types of relationships where partners easily get attracted to each other are C2 and C3. These are the most common of all happy marriages. Keep in mind that even complementary types may have problems with each other because of issues outside of Socionics."
R.K. Sedih, "Informational psychoanalysis" (Conflict Relations):
"Partners usually find each other quite interesting. Among socionists the most wide-spread name for this type of relations is "conflict". This is justified only on low level of interaction when both partners are poorly developed and un-dualized. In this case, partners not realizing it will hit each other's weakest spots. This is a very difficult situation if both of them have to live together, sharing a room for example. Situation improves if even one partner is dualized. In this case partners can affect each other positively and even derive benefit from these relations. This aspect of interaction is satisfactory only if there is tolerance between partners. In socionics, there is a tradition to consider this interaction as the most harsh and uncomfortable for the individual. My own research has shown, however, that it is almost always not the case. Over many years of studying socionics, I have not found any cases of such classic conflict as described by A. Augustinavichiute. Our observations and some recent theoretical developments suggest that in general this type of relation falls into the same level of comfort as semi-duality and activation relations."
I think Ni is strongly related to episodic future thinking and episodic counterfactual thinking.
"Thinking about the future is an integral component of human cognition – one that has been claimed to distinguish us from other species. Building on the construct of episodic memory, we introduce the concept of ‘episodic future thinking’: a projection of the self into the future to pre-experience an event. We argue that episodic future thinking has explanatory value when considering recent work in many areas of psychology: cognitive, social and personality, developmental, clinical and neuropsychology. Episodic future thinking can serve as a unifying concept, connecting aspects of diverse research findings and identifying key questions requiring further reflection and study."
http://imgur.com/qnmDCiu (mk2 Super-Id block contains 3D and 4D functions)
Why is ILI's Ti- (and Fe+) the 5th function? Because it is obvious that ILI's Ti- is an accepting function. This order is also logical: Ni+ Te- Si+ Fe- // Ti- Ne+ Fi- Se+ ... For example, Ni+ is the most conscious function, so Se+ is the most unconscious function. Furthermore, it is very likely that Se+, Fi-, Te+ and Si- are the most unconscious functions (Id), since ILI often neglects social relations, health and material wealth.
Also, a person cannot get energy from within and from other people, so there are no real ambiverts. Hence, my subtype system had to be modified.
This is my new model.
http://imgur.com/5M4UGLo (mk1 has the same structure as Model A)
Model D builds on Socionics Model A and Model B, and to some extent on Harold Grant's model. It consists of two sets of functions; main functions and secondary functions. These are separate systems (of functions), but for the most part it is only the main system that works independently. For example, information can go from ILI's Ni+ directly to Se-, then to Ti+ and finally back to the main system (Fe-). This is why we often don't see typical IEE behavior in ILI. But if an ILI extroverts a lot, then he or she occasionally uses the complete secondary system.
The basic structure of Model A, Vladimir Yermak's definitions of +/- functions and Viktor Gulenko's approximate descriptions of +/- functions apply to Model D:
Model D is different from Model B in three ways:
1) The model does not use information aspects/IM elements. It uses Jung's/Berens' cognitive processes with some improvements: Te is about logical deductions, EDIT: Te is indirectly related to facts, Si is related to comfort, EDIT: Si notices details of objects, EDIT: Ni is about scenario thinking etc. However, it is possible to replace the Jungian cognitive processes with information aspects/IM elements. It would still be a very accurate model.
2) The secondary functions are noticeable almost every day, unlike Bukalov's "Shadow functions" which are noticeable in some special situations. The conscious/mental functions in the secondary system are much more obvious than the unconscious/vital functions in the main system. This corresponds with Irina Eglit's and Vladimir Yermak's research on plus and minus functions.
3) Aleksandr Bukalov claims that ILI's Shadow Ego is NiFe. I claim that ILI's second Ego is NeFi.
Is there any evidence that supports Model D? Yes. For example, ILI can spend months or years on a new theoretical model (Ti-) but has no patience whatsoever for concrete technical problems, like repairing the car (Ti+). Also, ILI oversimplifies any solutions (Ti+) to physical threats (Se-). ILI's Ti+ is obviously very weak. Another example is IEI who is more creative than ILI. This makes no sense if both IEI and ILI have Ne as Ignoring function in Model A. A third example is LII who sometimes has surprisingly high emotional intelligence (Tina Fey).
A key advantage of Model D is that it explains why people of the same type can be so different from each other. This is my new subtype system:
1) Strengthening one function produces a domino effect across the entire functional layout, so all strong (or weak) functions are strengthened and all weak (or strong) functions are weakened.
2) Some subtypes use their secondary functions more than others due to variations in extraversion/introversion.
3) 100 subtypes are needed in order to accurately describe all kinds of personalities. Hence, a very introverted or extroverted person with very strong Ego and Id functions is subtype 1,1. An ambivert with very strong Ego and Id functions is subtype 1,10. Here are some examples: David Keirsey Jr is LII-8,2. Tina Fey is LII-7,8. Bill Gates is LII-2,7. Seth Lloyd is LII-1,4. And Terence Tao is LII-1,1.