(About this image)*
So, occasionally I find myself perusing the internet to see what sort of type conversations are happening. Normally, I stick to choice blogs or books, but occasionally, I wander on to message boards or Youtube videos to see what The Kids Today(tm) are saying. In doing so, I've noticed a lot of attention to the idea of a dominant-tertiary "loop" (I believe inspired by and adapted from Lenore Thomson's interesting but highly idiosyncratic book). The idea behind it seems to be that when we have trouble accessing the opposite attitude, we'll tap into our third function, since it's in the same attitude as the dominant. It rests on the rather questionable assumption that our less conscious functions provide better access than a more conscious function in the same attitude. I'll cite the examples I've seen, focusing on INFJ since that seems to be the most frequently referenced loop. (I've read them for other types, though, and think many of the criticisms could be generalized to the loop concept overall.)
I. Meaningless Loops
In the first case, there's a meaningless, but mostly harmless use of the loop concept. In this case, typical behavior that is generally thought of as being negative is attributed to the "loop" but really is describing what the top two functions do. For example, I've seen people attribute to the Ni/Ti loop feelings of social anxiety and insecurity: worrying that the girl you heard making fun of someone was talking about you, worrying about a weird look you got, an "off" attitude, and in general being sensitive to cues of possible rejection.
Now, I don't dispute that INFJs do this. What I deny, though, is that these qualities partially belong to the tertiary Introverted Thinking function. In fact, the tendency to notice little social cues is actually something that accompanies Feeling in general, but Extraverted Feeling especially. It's one reason why ITPs tend to have such trouble socially. They genuinely do not know what these social cues mean, and they tend to frequently miss them altogether. It's true that Introverted Thinking is about "analysis" but it's a completely different kind of analysis: it's impersonal, detached analysis. Introverted Intuition seeks out (among other things)patterns, symbolism and constructs through which they might understand the world, Extraverted Feeling pays careful attention to interpersonal cues (and is often expressive in using them with others), combining to make the INFJ sensitive to nuance. (Introverted Feeling can be equally hypersensitive to cues but is not always as skilled at communicating the appropriate social cues to others.*) There's no actual Introverted Thinking at work here, though. If you talk to an INTP or ISTP about a "cue" they've been giving you, (and this sometimes happens with ENTPs and ESTPs as well, who have auxiliary Introverted Thinking) they'll often not have the foggiest notion of what you're talking about, and may in fact become frustrated that they're being asked to account for something they had no idea that they were doing. They'd much prefer to turn their attention to some sort of logical problem (be it technical, philosophical, scientific or just a puzzle) where they don't have to think about other people's feelings. So, how on Earth could this be an Ni/Ti loop? Furthermore, if such attention were to become debilitating and you sought therapy, the most common method of therapy would be to help you deal with it by generating and testing hypotheses, looking for flawed assumptions, examining evidence in a dispassionate manner--all Thinking characteristics. So, one could argue that the problem isn't that you have by-passed Extraverted Feeling and are falling back on your thinking function, but rather that you're too reliant on your Feeling and need to incorporate Thinking more.
II. By-Passing the Auxiliary
The second use of it that I've observed is to explain away evidence that would call that type into question. So, for someone that really does engage in more detached analysis than social harmonizing, but for whatever reason identifies as INFJ, they can still claim it as their type.
Now, it is entirely possible for extreme introversion to cause one to not develop their auxiliary function in the extraverted attitude (and vice-versa). However, that doesn't mean the person will have a more developed third function than second. That's a lot like missing your flight from Chicago to New York and instead hopping on a plane going from Chicago to Paris, checking into a hotel, doing some touristy stuff, grabbing dinner, and then complaining that you need to figure out a way to get back to New York. Why wouldn't you just find another way to get to New York?
Well, it's the same way with the auxiliary. If you can't find a way to extravert your second function, you're not going to resort to the third, less conscious function, you're just going to use the second function in the preferred attitude. To reiterate what I said here:
Your auxiliary, by virtue of being the auxiliary, is the second most conscious function. If your thinking is more developed than your feeling, you aren't an INFJ, you're an INTJ. Now, early Jungians thought that the auxiliary was in the same attitude as the dominant. Even the MBTI manual allows, in the chapter on counseling, for people to develop an auxiliary that is in the same attitude as the dominant. Note on page 226:"Some Extraverts seem to use their auxiliary function as well as their dominant function in the Extraverted attitude. This makes them appear to others as 'extreme Extraverts.'" and, further down the page, "Some Introverted clients introvert both their dominant and auxiliary functions, making them appear as 'extreme introverts.'" If you're an INFJ but your introversion is extreme, then you may see more Introverted Feeling in your personality. If, however, you see neither Introverted nor Extraverted Feeling in your personality, but you do see Introverted Thinking, then you may want to examine whether INFJ is the best fit for you.
The confusion stems, I think, from how the system is presented. When presented to the general public, normal type development is assumed, since for most people that will be the case. The alternate manifestation is addressed in clinical/counseling settings, though, since there's a much greater likelihood of encountering individuals with atypical type development.
III. A Word on Paranoia
Some of the Ni/Ti loop theories have focused, as I said, on sensitivity to nuance. However, in some cases, it's been interpreted as full-blown paranoia and conspiracy theories. However, when social anxiety becomes paranoia, especially when accompanied with retaliation for perceived slights, you're seeing the manifestation of the inferior function of dominant introverted feeling. In describing the eruption of the inferior function of the Introverted Feeling type, Jung states:
She begins consciously to feel 'what other people think.' Naturally, other people are thinking all sorts of mean things, scheming evil, contriving plots, secret intrigues, etc. In order to forestall them, she herself is obliged to start counter-intrigues, to suspect others and sound them out, and weave counterplots. Beset by rumours, she must make frantic efforts to get her own back and be top dog. Endless clandestine rivalries spring up, and in these embittered struggles, she will shrink from no baseness or meanness and will even prostitute her virtues in order to play the trump card. (PT:644)
This doesn't mean just fleeting insecurities, wondering if someone likes you, or occasionally feeling snubbed by that standoffish waiter (or customer). If, on the other hand, you're so convinced that someone is so against you that you set out to ostracize them, engage in a campaign of misinformation or otherwise undermine them out of the conviction that they are or will do the same to you, then you're seeing an Introverted Feeling type whose Inferior Extraverted Thinking has severely got the better of them. In this case, the fictitious Ni/Ti loop may be doing more harm than good because it's preventing the person from facing their inferior function, since not are they not dealing with the right one, but they've actually convinced themselves that they're relying too much on their thinking function when precisely the opposite is true.
* From Morgan's Tarot deck. The actual meaning of the card is "This card may mean that it is all right to be what you are. Or, the situation is radically different from what it normally is. Or, despite the fact that everything is okay, it doesn't feel that way. Refreshing influences rather than draining influences may dispel your anxiety." I thought it was rather indicative of how INFJs often feel.
**I think this may be what's behind a lot of Introverted Feeling/Extraverted Feeling misunderstandings. With Thinking types, the inattention to those cues make it more obvious what's going on, but with IFPs, a certain sensitivity is demonstrated, but they may "drop the ball" on certain social niceties, which can enflame insecurities.