MBTI types that best represent Jung's types

[Shadow Play]

For my comparison, I am primarily concerned with evaluating type accuracy from a Jungian lens, meaning many of the views expressed are not my own viewpoints. Although I believe the modifications Myers and Briggs had made to Jung's type theory were necessary modifications - particularly shifting abstraction from Introversion to Intuition - Myer's biggest mistake was assigning inconsistent function stacks to her sixteen dichotomy types. In particular, she made the mistake of assigning introverted auxiliary functions to extraverts and extraverted auxiliary functions to introverts, when Jung believed the auxiliary shared the orientation of the dominant when sufficiently differentiated. From a Jungian standpoint, it makes no sense for an INTJ and an ENTJ to share the same functions and for an INTJ and an INTP to have completely different functions.

More importantly, Jung did not even believe in eight functions. He instead believed there were the same four functions in every individual with varying preferences, and each function possessed both an objective and a subjective orientation. He believed the majority of people were close enough to the middle on extraversion and introversion where they're effectively ambiverts, and the types he described tended to only manifest in individuals with a distinct preference for either temperament. Jung conceived of eight types grouped between the extraverts and introverts, with each of the extraverted and introverted types having one of the four functions in a dominant position.

To what extent Myers believed functions were genuine or not is a matter of debate, but in practise, MBTI function theory is a category mistake. The dichotomies are the main event of MBTI. People test for their dichotomies, and through obtaining data from test results, MBTI professionals correlate type preferences with various personality traits to produce statistical trends. The functions do not have a separate existence beyond those descriptions jerry-rigged to their equivalent two-dichotomy combinations, such as Ti to TP and Ni to NJ. As a consequence of jerry-rigging functions, the functions themselves had been modified to fit with their respective types, leading to MBTI types which often share little in common with their Jungian counterparts.

The following post is an attempt to compare Jung's types from Psychological Types with their closest corresponding MBTI types.

Extraverted Thinking: ETJs
Extraverted Feeling: EFJs

Extraverted Sensing: ESPs
Extraverted Intuition: ENPs (arguably any of the EPs)

Introverted Thinking: INTs
Introverted Feeling: Introvert

Introverted Sensing: IPs (arguably more so for INPs)
Introverted Intuition: INPs

I have a number of reservations.

• ESJs are a closer approximation of Extraverted Rationals than ENJs. Jung believed extraverts tended to conform to and enforce the values of the society they live in, and while this is true for SJs as described by Myers and Keirsey, ENJs are just as likely to be agents of change and reform in the world, be they as leaders, activists, or revolutionaries.

• Out of Jung's eight types, Extraverted Sensing is the most recognisably similar to its MBTI equivalent of ESPs, although it's still a caricature of an average ESP's hedonistic tendencies.

• I think Jung's description of Extraverted Intuitive type is a better fit for ESPs than it is for INPs. A fair amount of INPs mistype as ENPs because they describe themselves as having this sort of intuition which explores possibilities in their own heads, and claim that looking like an introvert is somehow consistent with being "the most introverted extraverted type." Jung did not believe in behavioural or cognitive extraversion and introversion, since he believed one's behaviour was a reflection of one's cognition on a temperamental level. Basically, if someone looks like an introvert, they are an introvert. In addition, Jung's Extraverted Intuitive type is more concerned with exploring possibilities in the external world, rather than exploring ideas in their own head as an Introverted Intuitive would do. They're described as the "merchants, contractors, speculators, agents, politicians" of the world. In order to find potential, they act towards things in the hopes their ventures bear fruit, and once all potential is exhausted, they move onto the next venture. This sort of opportunism is something which could easily describe ESP entrepreneurs, for example, but it doesn't describe INPs who lie in bed daydreaming.

• Out of Jung's four "temperaments," the Introverted Rationals are the ones with the most ambiguous MBTI correspondent, whereas Extraverted Rationals, Extraverted Irrationals, and Introverted Irrationals correspond well with EJs, EPs, and IPs, respectively. While EJs like structure and control over others and the world around them, and while both EPs and IPs chaff under structure and prefer exploring their perceptions externally or internally, Introverted Rationals - as described by Jung - prefer to structure their thoughts and feelings internally based on subjective data, meaning they could fit both IJs and IPs equally well.

• Introverted Thinking is an equally valid fit for both INTs, not just INTPs, and I'd go as far as to say it fits INFs better than it does ISTs. The emphasis of Jung's Introverted Thinking is on abstract trains of logic which de-emphasise facts in lieu of underlying ideas and patterns, sometimes favouring a slow, belaboured approach at the expense of efficiency, and is generally more concerned with theories than on solving immediate problems. In other words, Jung's Introverted Thinking types are natural scholars. I think the average IST would be too practical and down-to-earth for that level of speculation.

• I really can't think of any particular MBTI type which properly fits with Jung's Introverted Feeling type. The MBTI function stacks state that IFPs are the Fi doms, but Jung's portrait of Introverted Feeling types having a cold severity about them doesn't fit, since IFPs tend to be the most warm and personable of the introverts on average. There's been an evolution from Jung's conception of Thinking and Feeling as logic vs. values to something closer to Big Five Agreeableness, and in Big Five terminology, Jung's Introverted Feeling type could be said to be not just low in Extraversion, but also low in Agreeableness and high in Neuroticism - although he thought all introverts were neurotic, since he believed introversion was a natural defence against the influence of the external world. It also doesn't make sense to characterise Feelers merely as people who "make decisions using their emotions," since any sane person will inform their decisions using facts and logic. Jung himself dithered about what Feeling actually was, going from claiming it's a different kind of rational process to Thinking, to claiming to be struck by people who consistently made decisions at the expense of reason.

• In contrast to its extraverted counterpart, the Introverted Sensing type is the one where MBTI types have diverged the most from Jung. Their official MBTI equivalents, the ISJs, are typically characterised as dutiful, attentive to detail, organised, and conventional minded. All of these traits fly in the face of Jung's Introverted Sensing type, which is essentially a basket case who, at their most unhealthy, mythologises the world as a place "where men, animals, railways, houses, rivers, and mountains appear partly as benevolent deities and partly as malevolent demons." Before you say "but aren't ISJs into traditions," remember that Jung believed introverts tended to reject traditions imposed upon them by others in favour of their own ideas and eccentricities. Even though Introverted Irrational types are described as the "most fruitless of men," Jung also regarded them as "an educational experience for the man who refuses to be blinded by the intellectual mode of the day."

• Like with all functions, MBTI descriptions of Ni as a "singular vision" tend to be jerry-rigged to descriptions of things NJs have in common, rather than representing Jung's original ideas about those types. The Introverted Intuitive type is a type who amuses themselves through flights of fancy. Instead of developing a singular vision, making plans and committing themselves to realising their plans, they're more inclined to constantly come up with all these zany ideas all the time without acting on any of them. When there's an emphasis on exploring ideas in one's own head, it usually leads to neglecting structure in one's own affairs. Hence why I have assigned INP to Introverted Intuition, and not INJ. Compounding the problem is Jung's own beliefs in visions and psychic powers which permeated his work, which lends to the Introverted Intuitive description the aspect of those types as prophets and seers. It's common for INTJs to read Jungian descriptions of Ni, and when they find they don't relate to them because they're overly mystical, end up doubting their own type. INTJs are natural sceptics who are inclined to poke holes in superstition and dogma. Science careers are the careers with the greatest average job satisfaction for INTJs, and INTJs are among the types most likely to be irreligious.

 

[Pionart]

Extroverted Thinking: ETJ
Extroverted Feeling: EFJ
Extroverted Sensing: ESP
Extroverted Intuition: ENP
Introverted Thinking: ITP
Introverted Feeling: IFP
Introverted Sensing: ISJ
Introverted Intuition: INJ

Seriously, it's as simple as that. If Jung's descriptions don't actually seem to line up like that, then he (or the more recent voices on the subject) didn't describe things properly and who cares.

INTJ and ENTJ have the same conscious functions, but having the functions in different orders leads to a different set of typical characteristics. INTJ and INTP have more similar characteristics in comparison, but this is because we are not a pure type, and types with the same first 3 letters just happen to go together, which has nothing to do with sharing the same functions or not.

 

[Shadow Play]

Extroverted Thinking: ETJ
Extroverted Feeling: EFJ
Extroverted Sensing: ESP
Extroverted Intuition: ENP
Introverted Thinking: ITP
Introverted Feeling: IFP
Introverted Sensing: ISJ
Introverted Intuition: INJ

Seriously, it's as simple as that. If Jung's descriptions don't actually seem to line up like that, then he (or the more recent voices on the subject) didn't describe things properly and who cares.

INTJ and ENTJ have the same conscious functions, but having the functions in different orders leads to a different set of typical characteristics. INTJ and INTP have more similar characteristics in comparison, but this is because we are not a pure type, and types with the same first 3 letters just happen to go together, which has nothing to do with sharing the same functions or not.

Jung did not think of types in terms of function stacks, but if he was to do so, he likely would have proposed three possible function stacks for each of the eight types (or sixteen types if we think a different auxiliary function changes the type to produce sub-types).

In Psychological Types, Jung described a pure Introverted Thinking type as having unconscious extraverted functions.

The counterbalancing functions of feeling, intuition, and sensation are comparatively unconscious and inferior, and therefore have a primitive extraverted character that accounts for all the troublesome influences from outside to which the introverted thinker is prone.

The same reasoning would apply to an Extraverted Thinking type or any of the other eight types, although the types Jung was describing were only "Galtonesque portraits" that intentionally excluded the differentiating aspects of an auxiliary function.

In his later work Individual Dream Symbolism in Relation to Alchemy, Jung described the auxiliary sharing the attitude of the dominant and the tertiary sharing the attitude of the inferior.

If we think of the psychological function as arranged in a circle, then the most differentiated function is usually the carrier of the ego and, equally regularly, has an auxiliary function attached to it. The "inferior" function, on the other hand, is unconscious and for that reason is projected into a non-ego. It too has an auxiliary function. ...

In the psychology of the functions there are two conscious and therefore masculine functions, the differentiated function and its auxiliary, which are represented in dreams by, say, father and son, whereas the unconscious functions appear as mother and daughter. Since the conflict between the two auxiliary functions is not nearly as great as that between the differentiated and the inferior function, it is possible for the third function — that is, the unconscious auxiliary one — to be raised to consciousness and thus made masculine. It will, however, bring with it traces of its contamination with the inferior function, thus acting as a kind of link with the darkness of the unconscious.

This can be rendered as three function models for, let's say, a Ti type with auxiliary N...
Pure Ti: Ti/Ne-Se-Fe
Standard Ti with N: Ti-Ni/Se-Fe
Ti with N and differentiated tertiary: Ti-Ni-Si/Fe

Jung spent more of Psychological Types describing extraverts and introverts than he did describing the functions themselves. In light of the overall context of that book, based on how much he emphasised all the ways in which extraverts and introverts are different, would it really make sense for Jung to conclude that an extravert and an introvert used the same functions? No.

The reason MBTI function descriptions don't match up with Jung's types is because they're jerry-rigged descriptions of specific two-letter dichotomies. Modern day descriptions of Si are glorified descriptions of SJs that get passed off as Si even if that's not what's actually being described. It's all lip service. Even actual functions proponents like Beebe and Nardi don't describe functions in Jungian terms. If INTJs and ESFPs share things in common that INTJs and INTPs don't, it should reflect in statistical data where you have TJ/FP and NJ/SP or TP/FJ and NP/SJ clustered together at opposite ends, but guess what? Those axes never show up in any of the data. INTJ and INTP only appear to be completely different with a heavy dose of Forer effect.

But hey, if you want to continue prostrating before the altar of St. Harold Grant, it's your choice.

 

[Pionart]

Jung didn't get everything right.

No idea what you're talking about with this Harold Grant guy. I base my conclusions on observation.

I observe people showing a function order as typically described, e.g. INFJ is Ni-Fe-Ti-Se-Ne-Fi-Te-Si.

I also observe alternate configurations being used but they are the exception.

Appeal to authority is going to be useless on someone who has based things on observation.

--

To clarify: the principles behind type are about how things actually manifest in reality, not about what Jung did or did not say on the topic.

 

[Pionart]

Also, I'm confused as to why you sound like a reckful clone.

 

[reckful]

Also, I'm confused as to why you sound like a reckful clone.

Confused?? I find it perfectly understandable.

 

[Pionart]

Confused?? I find it perfectly understandable.

But we already have a reckful why do we need a second??

Ah, it's fine.

 

[reckful]

But we already have a reckful why do we need a second??

Ah, it's fine.

Since there are about a gajillion HaroldGrantians, I will continue to consider myself part of the noble underdog contingent.

 

[Shadow Play]

Confused?? I find it perfectly understandable.

Well, well, well, speak of the devil...

Jung didn't get everything right.

No idea what you're talking about with this Harold Grant guy. I base my conclusions on observation.

I observe people showing a function order as typically described, e.g. INFJ is Ni-Fe-Ti-Se-Ne-Fi-Te-Si.

I also observe alternate configurations being used but they are the exception.

Appeal to authority is going to be useless on someone who has based things on observation.

--

To clarify: the principles behind type are about how things actually manifest in reality, not about what Jung did or did not say on the topic.

Harold Grant is the geezer who came up with the forum famous function stack which claims INTPs and INTJs have completely different functions, and that the tertiary function somehow shares the temperament of the dominant while the auxiliary does not.

You're mistaken if you think I hold Jung as an authority, because I don't. While Jung did have a handful of good ideas here and there, such as a few observations about extraversion and introversion, Jung was for the most part a quack whose mystical ideas about the collective unconscious, synchronicity, and ESP do not hold up under any scrutiny. Look no further than Jordan Peterson if you want a real Jung fanboy. The only reason I invoke Jung as a source at all is because everyone around here claims to favour a Jungian approach towards typology, and yet their ideas about typology aren't anything Jungian at all. They're instead a bastardised Frankenstein's monster of bits of Jung, MBTI, Harold Grant, Socionics, and Enneagrams all crudely stitched together, and this abomination is made out to be the ideal typology system. And when some folks do call out the emperor for wearing no clothes, you block your ears to the evidence and believe the same bullshit you've always believed.

 

[Luminous]

Shadow Play, what typology system(s) do you have more respect for?

 

[Pionart]

Well well well, speak of the devil...



Harold Grant is the geezer who came up with the forum famous function stack which claims INTPs and INTJs have completely different functions, and that the tertiary function somehow shares the temperament of the dominant while the auxiliary does not.

You're mistaken if you think I hold Jung as an authority, because I don't. While Jung did have a handful of good ideas here and there, such as a few observations about extraversion and introversion, Jung was for the most part a quack whose mystical ideas about the collective unconscious, synchronicity, and ESP do not hold up under any scrutiny. Look no further than Jordan Peterson if you want a real Jung fanboy. The only reason I invoke Jung as a source at all is because everyone around here claims to favour a Jungian approach towards typology, and yet their ideas about typology aren't anything Jungian at all. They're instead a bastardised Frankenstein's monster of bits of Jung, MBTI, Harold Grant, Socionics, and Enneagrams all crudely stitched together, and this abomination is made out to be the ideal typology system. And when some folks do call out the emperor for wearing no clothes, you block your ears to the evidence and believe the same bullshit you've always believed.

Evidence? I just told you I have plenty of evidence for the function model I use. I see it every day. If I've directly experienced something to be true, you'd have to show me how it's false in terms of what I've already seen, not provide half-baked so-called evidence.

And LOL @ calling Jung a quack. You don't believe in things like synchronicity? You've never experienced it? Riiight. Well, you keep on living in your world, I'll live in mine.

But if you want to act like there's no evidence for the function model which puts the auxiliary as the opposite orientation and the tertiary as the same orientation as the dominant... well, you're sadly mistaken. I don't believe it because I was told it, I actually investigated it to see if it was true, and it turns out it is. INTP and INTJ actually do have the opposite conscious functions.

Different thinkers have over the past century offered different additions to the typological system we use today. There's a ton of misinformation around regarding it, but this "Harold Grant function stack" is one of the more solid aspects.

 

[Shadow Play]

Shadow Play, what typology system(s) do you have more respect for?

I find all typology systems limited by their very nature. They can only provide broadstrokes of ways in which people are similar or different, based on which traits they happen to possess or not possess, and some typology systems will inevitably concentrate on different traits than others. Whether they are soft sciences or pseudosciences, typology systems are an attempt at observing the wind based on which way the wind blows, but they lack the means to observe patterns in one's neurology. We can't be certain of which dimensions of personality are the most valid dimensions to be measured. The only confirmed dimension of personality at this point in time is extraversion and introversion, and Jung's crowning achievement was pioneering the notion of two different types of people based on how outgoing or recluse they were. I don't think it's necessary for them to explain everything about personality theory, though.

Thus, there isn't any one typology system I fully respect, although not all typologies are created equal. Out of the ones I'm aware of, the MBTI dichotomies and the Big Five Factors are the ones I appreciate the most, on the basis of being testable models which attempt to quantify real dimensions of personality. That puts them in a different league from Astrology, the Four Temperaments, Enneagrams, and any cognitive functions models, which due to their subjective nature, are prone to Forer effect. Despite their relative advantages, they're far from flawless. See my criticism of the MBTI here for more details. I'm sure there are plenty of more obscure typology systems out there of which I'm unaware. I've heard of the HEXACO model, but I know nothing about it.

I had recently taken to studying the Enneagram, but I find the system incoherent. There is no clear reason why nine core motivational types are the most sensible way to split them up, it doesn't make sense for those core motivations to be mutually exclusive, and the grouping of motivations into three groups is arbitrary. Even if I was to overlook the New Agey overtones of its design, the Enneagram is unwieldy in practise due to the sheer multitude of possible types; there are 7776 possible tritypes according to my calculations. I suspect my tritype would be 541 sp/so, but who knows?

Evidence? I just told you I have plenty of evidence for the function model I use. I see it every day. If I've directly experienced something to be true, you'd have to show me how it's false in terms of what I've already seen, not provide half-baked so-called evidence.

And LOL @ calling Jung a quack. You don't believe in things like synchronicity? You've never experienced it? Riiight. Well, you keep on living in your world, I'll live in mine.

But if you want to act like there's no evidence for the function model which puts the auxiliary as the opposite orientation and the tertiary as the same orientation as the dominant... well, you're sadly mistaken. I don't believe it because I was told it, I actually investigated it to see if it was true, and it turns out it is. INTP and INTJ actually do have the opposite conscious functions.

Different thinkers have over the past century offered different additions to the typological system we use today. There's a ton of misinformation around regarding it, but this "Harold Grant function stack" is one of the more solid aspects.

Your so-called "evidence" is nothing more than Forer effect. You take these patterns and you project them onto people you know, and you selectively pick and choose which traits fit within your system. The problem is you're operating under the assumption the Grant stack is correct, and from that conclusion, you work backwards, leading to all sorts of mental gymnastics. Forer effect asides, I don't know any of the people you know, so as far as I'm concerned, they may as well not exist. I could play at the "confirm my opinions with subjective experience" game, too, if I wanted, but that would be pointless.

 

[Pionart]

Your so-called "evidence" is nothing more than Forer effect. You take these patterns and you project them onto people you know, and you selectively pick and choose which traits fit within your system. The problem is you're operating under the assumption the Grant stack is correct, and from that conclusion, you work backwards, leading to all sorts of mental gymnastics. Forer effect asides, I don't know any of the people you know, so as far as I'm concerned, they may as well not exist. I could play at the "confirm my opinions with subjective experience" game, too, if I wanted, but that would be pointless.

Ok, so I take a pattern, in this case function order, and I project it onto a person. I try out different instances of that pattern until I find the one that sticks. Or, alternately, I make a judgement call about what a particular aspect of a person, e.g. the tone of their voice, refers to in terms of a cognitive function, and then I look for which order they go in.

So, no I'm not taking the Harold Grant function order as a premise, I'm taking the cognitive functions as a premise, and then derived the Harold Grant function stack based on that. So I still do look for patterns that fit with the cognitive functions.

But the way I see it, if projecting a particular pattern onto something allows you to understand something better, then isn't it appropriate to use it? No model is true, but some models are useful.

 

[Shadow Play]

Ok, so I take a pattern, in this case function order, and I project it onto a person. I try out different instances of that pattern until I find the one that sticks. Or, alternately, I make a judgement call about what a particular aspect of a person, e.g. the tone of their voice, refers to in terms of a cognitive function, and then I look for which order they go in.

So, no I'm not taking the Harold Grant function order as a premise, I'm taking the cognitive functions as a premise, and then derived the Harold Grant function stack based on that. So I still do look for patterns that fit with the cognitive functions.

But the way I see it, if projecting a particular pattern onto something allows you to understand something better, then isn't it appropriate to use it? No model is true, but some models are useful.

I know people use visual typing, but geez, oral typing is a thing as well?!?

 

[Pionart]

I know people use visual typing, but geez, oral typing is a thing as well?!?

Yeah, it's one of the best methods there are.

Problem?

 

[Pionart]

Catch up or be left behind.

 

[Shadow Play]

Yeah, it's one of the best methods there are.

Problem?

If by "best," you mean "best methods at producing ridicule," then yes, you are correct. "Oh look, someone has a goofy look when they smile, therefore they're ENFP!" "Hmmm, someone seems to be hesitating before they speak for some reason, could it be that they use Ti?"

 

[hurl3y4456]

If by "best," you mean "best methods at producing ridicule," then yes, you are correct. "Oh look, someone has a goofy look when they smile, therefore they're ENFP!" "Hmmm, someone seems to be hesitating before they speak for some reason, could it be that they use Ti?"

There are definitive patterns that one can use to get an idea of their function stack....For instance, someone who uses word play/puns regularly most likely has Ne in their upper stack. Fe corresponds to external emotion/external control and Fi corresponds to internal emotion/internal control.....Hence, Fi users will be less expressive....Therefore, perhaps INTJ's have a propensity for monotonous voice. Ni is inward focused yet projects itself from the present moment into a far reaching Domain...Therefore, Ni users will have a propensity to drift off into space....However, this corresponds to introversion usage in general. Thus, those with introverted dominant functions will have a higher probability to lose awareness of surroundings. Extroversion decreases time of reaction....That is, an extroverted thinker is more likely to answer a question definitively at a faster rate because the mind is adapted to processing external stimuli on the run whereas introverted thinkers delve deep into a particular concept to understand it to the core.....Hence, introverted thinkers will tend to pause before arriving at an answer.

 

[Shadow Play]

There are definitive patterns that one can use to get an idea of their function stack....For instance, someone who uses word play/puns regularly most likely has Ne in their upper stack. Fe corresponds to external emotion/external control and Fi corresponds to internal emotion/internal control.....Hence, Fi users will be less expressive....Therefore, perhaps INTJ's have a propensity for monotonous voice. Ni is inward focused yet projects itself from the present moment into a far reaching Domain...Therefore, Ni users will have a propensity to drift off into space....However, this corresponds to introversion usage in general. Thus, those with introverted dominant functions will have a higher probability to lose awareness of surroundings. Extroversion decreases time of reaction....That is, an extroverted thinker is more likely to answer a question definitively at a faster rate because the mind is adapted to processing external stimuli on the run whereas introverted thinkers delve deep into a particular concept to understand it to the core.....Hence, introverted thinkers will tend to pause before arriving at an answer.

You're half-right, so I'll give you credit for trying. Yes, it's true that extraverts and introverts can be visibly different in their behaviour, and these visible differences are indeed reflective of temperamental differences to at least a certain extent. As Jung himself noted, "what fills the extravert's heart flows out of his mouth, but the enthusiasm of the introvert is the very thing that seals his lips."

However, you're thinking of expressiveness in terms of functions, not temperamental dimensions of personality. If by Fe and Fi, you mean those who supposedly have Fe or Fi in their function stacks regardless of their level of extraversion, that would be an error. Firstly, when Jung described Extraverted Feeling and Introverted Feeling, he was describing feeling as it consciously manifested in all extraverts or introverts, respectively. It wouldn't make sense for an ENFP to be an Introverted Feeler or for an INFJ to be an Extraverted Feeler. Secondly, even if you're of the opinion that the MBTI represents an improvement of Jung's theory, one of Jung's concepts that got carried over is the notion of extraversion as the primary source of one's expressiveness. This is a consistency between both theories. Thirdly, the Big Five model - which overlaps with the MBTI - has demonstrated that expressiveness is primarily a trait characteristic of extraversion, and although traits could potentially overlap between dimensions, this is one dimension where it does not.

Besides, I was specifically taking issue with typing based on mannerisms, such as concluding someone is of a certain type because they say "umm..." a lot, or because they like to gesticulate, or because they smiled a certain way. It's akin to staring at tea dregs to predict the future.

 

[hurl3y4456]

You're half-right, so I'll give you credit for trying. Yes, it's true that extraverts and introverts can be visibly different in their behaviour, and these visible differences are indeed reflective of temperamental differences to at least a certain extent. As Jung himself noted, "what fills the extravert's heart flows out of his mouth, but the enthusiasm of the introvert is the very thing that seals his lips."

However, you're thinking of expressiveness in terms of functions, not temperamental dimensions of personality. If by Fe and Fi, you mean those who supposedly have Fe or Fi in their function stacks regardless of their level of extraversion, that would be an error. Firstly, when Jung described Extraverted Feeling and Introverted Feeling, he was describing feeling as it consciously manifested in all extraverts or introverts, respectively. It wouldn't make sense for an ENFP to be an Introverted Feeler or for an INFJ to be an Extraverted Feeler. Secondly, even if you're of the opinion that the MBTI represents an improvement of Jung's theory, one of Jung's concepts that got carried over is the notion of extraversion as the primary source of one's expressiveness. This is a consistency between both theories. Thirdly, the Big Five model - which overlaps with the MBTI - has demonstrated that expressiveness is primarily a trait characteristic of extraversion, and although traits could potentially overlap between dimensions, this is one dimension where it does not.

Besides, I was specifically taking issue with typing based on mannerisms, such as concluding someone is of a certain type because they say "umm..." a lot, or because they like to gesticulate, or because they smiled a certain way. It's akin to staring at tea dregs to predict the future.

I haven't read much into Jung's work, so I'll need to get his perspective regarding the functions to further my understanding (if I choose to accept it).
Now, I agree typing based on mannerisms would not be very accurate, if at all since there's large variation regarding how each function manifests and the ratios at which each function is expressed. Certain mannerisms may dictate certain behavior at the extremes (very high Ti, Ni, exc), however, the interplay between each function causes a masking effect. Saying "umm" a lot may indicate insecurity/lack of confidence or unpreparedness during speeches, but it also could imply someone needs time to coalesce their thoughts together (introversion). It could also be related to processing speed or become a habit (speech pattern).

Regarding smiling and Fe/Fi usage, I'd say that for high Ti users, Fe is childlike (harder to control)....thus, it tends to be spontaneous, reactive, and impulsive....similar to a sine function with high amplitude where the y axis denotes the magnitude of emotion and x axis corresponds to frequency....Although emotional frequency will be event dependent and hence, will change. Since the emotion is harder to control, the frequency of occurrence should be reduced....High Fi users will have a firm grasp of emotional input/output and tend to be reclusive in terms of expressing it to others unless the person knows them well (trusted)....Since they internalize their emotions (meaning the energy derived from an emotional response is extended beyond the surface), it will most likely take them longer to recover from an emotional event. I am an Fe user who is sensitive to the negative emotions of others....Their emotions seem to translate within me and cause a negative reaction (externally derived).

Exhibiting gestures (in general) is related to external energy and emotion, so someone who is an extrovert with higher feeling functions may have a higher probability of using them, however, it's not fully definitive. It could also be related to well being, which is dependent on health/hormones or even related to neurotransmitter output....Perhaps someone with higher serotonin output smiles more frequently (makes sense logically). I have noticed that I joke around more freely when I intake a lot of sugar or alcohol, which both stimulate a temporary neurotransmitter response. Since smiling pattern is a function of muscle contraction/retraction and hormones dictate fat/muscle ratio, it will follow that there will exist a relationship between smiling and gender. Muscle adds tension (promoting more resistance + mass per unit volume), which requires more force to initiate upward movement. Of course, the effect of gravity and age over time will exemplify this effect as well. I've seen the video on "Fe vs Fi smiling" and I think there's too many variables that come into play to relate such functions in a 1-1 manner.