Each IM element has a generic agenda. However, these agendas also undergo specification in particular circumstances. Se is responsible for making an impact, but what impact do we want to have? Te is responsible for gathering resources, but what resource do we need? The leading function's agenda is pursued without limit, and primarily for its own sake: when perceived as achieved, it results in a strong feeling of immediate psychological satisfaction, and when perceived as unfulfilled, it results in a feeling of dissatisfaction. The suggestive function is similar. The creative and mobilizing functions are also satisfying, but not as much. As one moves downward in the mental and vital loops, the satisfaction produced by achieving an element's agenda becomes less and less—until we reach the vulnerable function (4th) and demonstrative functions (8th), which really do not provide any psychological reward and are used merely as tools. The main reason these lower functions are used is in response to specific programs or tasks set by the function directly above them.1 These programs (or information) flow from extroverted to introverted elements, and vice versa. A condition necessitates an activity that produces that condition, and an activity necessitates a condition in which it can be performed.

The relationship of blocking (extroverted irrational with introverted rational, or extroverted rational with introverted irrational) represents direct causality, or flow of information. However, information elements can be blocked in two different ways: Ti Ne (or Ne serving Ti), as exemplified by the type LII, is one blocking, but Ne Ti (Ti serving Ne) is a different blocking. To properly see this relationship, it is necessary to split each information element into plus and minus versions, one sign being for one orientation of the loop and the other for the other one. So we have -Ti-Ne-Fi-Se-Ti... but also +Ti+Se+Fi+Ne+Ti... and we similarly have +Te+Ni+Fe+Si+Te... but -Te-Si-Fe-Ni-Te... Each signed function directly corresponds to the type that has that function as its first function—the sign indicates whether the corresponding type is Positivist or Negativist. So the relationship of blocking corresponds to the supervision type relationship, and the mental and vital loops correspond to supervision rings.2 We will often reuse type relationship names for IM element relationships, in order to avoid unnecessary multiplication of terminology.

Gulenko's Model G also uses these element signs, and my definitions overlap considerably with his, but hopefully also introduce greater precision and conceptual clarity. I also believe that it is impossible to fully understand the 16 signed elements without also having a 16-function model. In Model A, information elements represent basic psychological faculties, and without any one of them no one can function properly in the world. If we want to maintain this interpretation—one of the most solid concepts underlying Model A—then everyone has to have access to the same elements; it is not possible for one person to only use an eight-element fragment. So let us define Model A2. It is very simple to construct: take two copies of a type's Model A, and label one copy "progressive" (with functions p1, p2, ... p8) and the other "regressive" (with functions r1, r2, ... r8). These two halves represent progression with respect to a type's natural values (flowing towards higher values), or regression respectively. We then assign signs to distinguish the elements on either side: for Negativist types, the progressive side has negative elements in the mental ring and positive elements in the vital ring. Their regressive side is the opposite. Positivist types have the opposite assignment of signs. Thus, the "progressive lead" function is the one described above, which corresponds to the type's main program in life—it is this agenda that determines the position of every other agenda in the type's psyche. There is a saying in Russian: "the type is the leading function." Model A2 makes this analogy precise. (Because of course, in Model A there are two types with each leading function.) Note also that Process types all share the same progressive (signed) elements, as do Result types.

The difference between static and dynamic elements plays an important structural role in Model A(2). However, the semantics of this dichotomy have been poorly understood. One possible definition is that static elements deal with discrete entities, while dynamic elements deal with continuous "fields".3

If one sees the world in terms of discrete entities, this demands the question: what are these entities? Well, an entity is something that one can (potentially) perceive, first of all. And not only can one perceive it, one can potentially also communicate with or interact with it, thus affecting it and being affected by it. This communication is determined by the entities' states and properties. In short, an entity is an information processor, that is, something or someone that takes in, processes, and emits informational signals.4

The key reason behind psychological lopsidedness is that we possess limited mental resources. In particular, there are many different entities in the world, and we need to decide which ones to request information from; we cannot consciously interact with all of them simultaneously. This task is the domain of Fi, which evaluates the properties of different information processors or sources, and measures one's affinity towards or away from them. This process does not require movement; it is done internally, so we say that Fi is an introverted element. Now, suppose that you have decided to "request information" from an entity. You have to actually narrow your scope of perception to focus on this particular entity. This is the task of Ne: it involves bringing something that is distant or abstract into the concrete realm. This is a kind of movement, yet is more on the mental level than physical level (the agenda is, anyway). However, we may metaphorically describe this as "movement towards" an information source. If you physically move towards something, it appears larger, and therefore takes up a greater fraction of your perception and mental resources. The intent is to expand the information about the object itself, even though this movement also effectively decreases information about everything-but-the-object. (Because mental resources are limited, expanding one part means contracting another, and vice versa—although the intent itself is asymmetric.) Fi here is setting the program for Ne, so by definition we are in the domain of positive information5 - which makes sense, because we are trying to increase information rather than decrease it.

Once you have focused on the information source, the next step is to mentally process or re-organize what you are perceiving, which is more detailed than what you were previously experiencing about the object. This is +Ti. Once the information has been processed, it becomes a part of your concept of the objective, concrete world, or Se. And, if one wants to change this concrete information, one can set the program to again evaluate the information source that one is engaged with, continuing the loop.

This process also happens in reverse: if you decide to disengage from an information source (-Fi), you have to "push it" away from yourself (-Se). This is unlike the case when something is not present with you—there are many things that are far from you (represented by the "abstract" trait of information), so this requires a choice between them (Ne). But there are only a few things close to you (represented by the "involved" trait of information), and to eliminate them requires force. To use force on a source, you have to understand the objective relationship between yourself and the source—say, what material advantages you have over it. This requires -Ti. And in order to see these objective relationships properly, you need to take a larger view of the situation (-Ne).

The above description is very abstract, so let's approach it from another direction:

Negative static tasks:

-Ti's task is to resolve different pieces of knowledge we have about the world into a smaller set of pieces. This involves resolving contradiction between different pieces of knowledge. Thus, -Ti reduces information, and more generally is responsible for unifying and simplifying what we know about the world using logical relationships like implication and equivalence, plus generalizations that take the form of universal laws. This is the Ti of the LII, which tends towards minimalism.

-Ne is the task of increasing the domain of our awareness, or the process of "zooming out". (But note that it is actually decreasing the information we have about the particular thing in focus, so it is a negative agenda.) This manifests as the goal to not be tied down, or to increase personal freedom and spontaneity by removing material attachments and limitations. This is the Ne of the IEE. It serves -Ti by allowing us to consider different possibilities or different aspects of the same thing. For example, there is the old story of the blind men and the elephant—each feels a different part of the elephant and decides that it is a pillar, a rope, etc. It is only by combining their perspectives that they are able to see the whole picture: -Ti is what recognizes the contradiction, and -Ne allows it to knit these together into a consistent whole.

-Fi is the evaluation of what information sources to disregard or to move away from—the often "harsh character judgment" of the ESI. It serves -Ne by telling it which information source should be disregarded among those present.

-Se's goal is to change or impact concrete states of affairs or information away from what they currently are. It serves -Fi by forcibly removing whatever source we want to get away from or remove from our space of awareness. And to influence things to be different, it is necessary to know that this is logically possible, that there is some logical connection between what is and what you want to be, which is -Ti. It also implies consideration of hierarchy and dominance—whether an entity (e.g., you) is able to influence another in the way that it wants, whether and how it should change its objective relationship to the object, etc.

Positive static tasks:

+Ti's task is to separate or subdivide information into more distinctions by using categories or classifications: yes and no, good and bad, right and wrong. This is the Ti of the LSI, which tends towards detail and maximalism by increasing the level of mental and physical order we impose on the world.

+Se is responsible for perceiving or demanding additional information about the actual way things are, as perceived. As information, it is the intensity of what appears to you in the moment. Thus, it serves +Ti by acquiring information about the world in front of us as it actually is, and by enforcing its distinctions. To come to know whether something is good or bad (true or false, etc.) it is necessary to distinguish it further among the set of entities present. Unifying pieces of information requires the opposite - to actually remove or ignore information to see the "essence" of it—hence, -Ne.

+Fi is, again, knowing which information sources to move towards, manifested subjectively as a feeling of sympathy, kindness, or fondness. All information comes from somewhere, so +Se has to know where to get its information. Fi is responsibility for knowing who or what we want to know more about, or who or what we would prefer to be in proximity to, and in general for deciding to move closer to one source rather than another.

Unlike -Fi, which can simply look at what is available, and decide to discard it by moving away, +Fi needs to make inferences beyond what is currently available, in order to speculate as to what they might have in store, if we were to move towards them. This is the task of +Ne: to "look inside" what is currently available and try to tease out its hidden or essential qualities. It is the intuition of prospects, of possibilities that are innate inside a thing (as opposed to the relations between the essences of different things, the domain of -Ne). This is the fascination-based Ne of the ILE, which is attracted towards particular entities, whether people, projects, ideas, etc.6

Now we consider the dynamic functions.

In general, dynamic elements view the world as a continuous field that information and substance flow through. The static elements concern information about discrete entities, and in general the relationship of things of the same type.7 Dynamic elements, by contrast, concern information about relationships between things of different types. An emotional state is something you have rather than something that has you. Same for resources, physical sensations, purposes/visions, etc. This flow of substance through space and time is something that we seek to understand and have control over, and this is the responsibility of the dynamic elements.

The irrational dynamic elements concern information which is either close to us (Si) or far from us (Ni), whether physically or causally. However, information that is close to us can become far from us, and vice versa. The rational dynamic elements are what concern this movement or conversion of information, in either direction. For example, both accumulation of utility and gathering of facts involves evaluating or transforming information or material obtained from an external source. And expending resources is the same process but in the opposite direction. Similarly, self-expression is conversion of internal information (one's emotional state, feelings, thoughts, etc.) into an externally intelligible form. The inverse process is opening oneself up to emotional input received from others.

Thus we see that the rational elements "go between" the irrational ones, and vice versa.

In more detail:

+Si is the attempt to create a positive condition in the here-and-now that is not yet present. This means improving the quality of what you are directly experiencing, and usually experiencing physically rather than in the imagination or mental realm of possibility.

+Te is the accumulation or gathering of utility and resources. This serves the attempt to create a positive immediate condition. Why? Take an example of a +Si goal: trying to cook a meal. In order to do this, you need to get tools to help you do this, and information about how to use them. The condition is not present, so you need to obtain information that can be communicated in a transmittable form: either symbolic form (the recipe in the cookbook) or material form (the utensils and appliances themselves).8 Accumulating these resources is the domain of +Te, or the LIE. The LIE is often more concerned with obtaining resources than actually putting them to practical use, or specifically managing the details of their usage.

If you are trying to accumulate resources that are not already present, this demands that you consider where and how you could best acquire them—in the future or realm of unrealized possibility (which is distant from you). Thus, +Te demands the consideration of +Ni, the task of progressing towards and focusing one's efforts on a desired abstract condition (a goal, plan, vision, dream, etc.). This is the Ni of the IEI. Trying to achieve a condition, however, does not necessarily imply that this condition is something drawn from the space of possibilities that you are presently aware of. So, the question is not how to achieve it. It demands instead that you "listen" to your emotional state (or others'), and determine how to best express it (+Fe).

+Fe is the goal of allowing increased flow of positive information about entities' internal states. Our emotional state is based on what we are currently experiencing, so to create a positive state, it is necessary and sufficient to create an immediate condition that produces this state, which is +Si. By contrast, to eliminate a negative state, it is necessary to think about what caused it in the first place (-Ni).

-Si is the task of alleviating a negative condition (or, fulfilling a need) that is present.9 Say that you are experiencing a negative condition, such as an itch. The recognition of why this condition bothers you requires looking into your state (emotional or otherwise) to determine why the present condition is not an expression of it (-Fe). If the need is more complex (such as an illness) it may require communicating the need externally to others (say by going to the doctor). The means to accomplish this are involved because it is about what you are actually experiencing, rather than what can be transmitted in an abstract form. Or to take again the example of cooking a meal—if you are cooking a meal for your friends, you need to obtain information by communicating with them and hearing what kinds of foods they do or don't want or like (Fe). This is because you are fulfilling a specific need, rather than just spontaneously making something enjoyable. -Fe is about catharsis or "getting rid of" negative states, and more generally concerns the output of information about one's state, i.e. self-expression.

-Ni is the task of avoiding an abstract condition or consequence — manifested subjectively as caution, fear, or anxiety ("I have a bad feeling about this"), and exemplified by the skepticism of the ILI. If you are trying to avoid an abstract condition, this implies that you already have one in mind, one that could potentially occur, or even already exists. (Say, starving over the winter due to not being able to trade or farm.) Therefore, this task demands consideration of how to most efficiently or effectively expend the resources that are present with you to avoid this condition. (Say, by eating a bit less food every day.) The task of expending resources in the best way, or finding the most optimal way to get from point A to point B, is -Te. And using resources implies that they are already near and available to you. So if you want to use them in the best way, you will need information about what is present, near, and directly experienced—which is Si.

To summarize, the supervisor transmits a program to the supervisee (as information), and the supervisee completes the corresponding task and subsequently transmits its results back to the supervisor, primarily in the form of information needed for the supervisor to then complete its task. We are only aware of this process up until the leading function—the fact that it serves the vulnerable function is something normally outside of our awareness. The leading function is like a man conducting an orchestra. His purpose is to please the audience, but if, even for a few seconds, he turns his attention to the audience (the vulnerable function) and away from the orchestra (the creative function), then the orchestra loses its direction and fails at its task.

for further development, see here