Is MBTI compatible with evolution?

[Tannhauser]

Let us consider MBTI in light of the theory of evolution.

Whether or not personality traits are a result of genetics or the environment or a combination, the genes of an individual are still deciding what kind of personality an individual is predisposed to.

If, for example, having an asocial personality would be maladaptive, genes which predispose for asocial behaviour would become weeded out.

Considering that all the various behavioural patterns cannot have exactly the same adaptive value, how does the MBTI then, so confidently posit that the population is divided into different 'types'?

If one proposes that it is beneficial to a group of humans to have a diversified range of types, this is wrong. The reason is that this goes exactly under the theory of social Darwinism (i.e. the theory that evolution selects for groups rather than individuals), which has shown to be incompatible with the theory of evolution.

So it seems that either, there is no such thing as 'types' -- instead there are just temporary behavioural habits which can change if you are forced to, or: MBTI is correct and the theory of evolution is wrong.

 

[Jennywocky]

With evolution, it should be made clear that it only amounts to whether or not the offspring can live long enough to reproduce. Minor maladaptation is inconsequential, it would have to be extreme maladaptation that would prevent reproduction. I'm not aware that personality variances are that extreme in nature to result in death before reproductive maturity.

Personality usefulness is also based on social context (different societies might vary the reward/punishment for different traits). So it's not consistent throughout the human species as to what is rewarded and what is not. In fact, even within the same tribe or smaller family, a set of traits that would be beneficial to a lone individual can be detrimental to the individual if it leaves them with no valuable role within the group because another individual has stronger manifestation of same traits, whereas a "weaker" set of traits can prove desirable if no one else in the group can manifest them and they are desirable to the group in SOME way.

Personality traits are also likely not simply recessive/dominant genes, they would seem to a combination of various genes working together and/or working in tandem with environmental factors that contribute to individualized wiring permutations. (We see windows of human development in various areas, where depending on what resources, nutrition, and stimulation the human gets in a particular window of time, certain degrees of growth are either implemented or not, with the outcome generally non-changeable or difficult to modify after the window has passed.)

IOW, it's more complicated than you're allowing for, and the only detriments that matters in regards to evolution are whether or not the offspring can survive to reproduce, which can hinge of biological and social context.

 

[Black Rose]

Considering that all the various behavioural patterns cannot have exactly the same adaptive value, how does the MBTI then, so confidently posit that the population is divided into different 'types'?

would this not eliminate economic roles also
being a shoe maker has a different adaptive value as an axe maker?
can not niches have the same quantitative value as successful reproduction?
and successful reproduction depends on mate selection,
different personalities have different criteria for mate asociality?

 

[Architect]

MBTI is evolution, or at least a product. I'm at a point in life where I'm seeing the next generation being adults and taking responsibility, rather an interesting perspective. I had a realization one day ... "oh shit, kids born in the 80's will soon have access to everything. Nuclear bombs, submarines, cities, the financial system. Will they know how to care for all of this?"

And then I realized that this is why there are so many Sensors, specifically ISTJ's and ISFJ's. These people are designed to carry forward traditions, good or bad. Without them things probably would fall apart. Finally I understand why these people that have been such an annoyance during my life are there for a reason. It was a great moment and I made peace with the annoying other side of society.

Likewise we intuitives are here to shake things up and make change.

 

[Tannhauser]

With evolution, it should be made clear that it only amounts to whether or not the offspring can live long enough to reproduce. Minor maladaptation is inconsequential, it would have to be extreme maladaptation that would prevent reproduction. I'm not aware that personality variances are that extreme in nature to result in death before reproductive maturity.

Here I disagree. Even microscopic maladaptions will compound throughout generations.

Personality usefulness is also based on social context (different societies might vary the reward/punishment for different traits). So it's not consistent throughout the human species as to what is rewarded and what is not. In fact, even within the same tribe or smaller family, a set of traits that would be beneficial to a lone individual can be detrimental to the individual if it leaves them with no valuable role within the group because another individual has stronger manifestation of same traits, whereas a "weaker" set of traits can prove desirable if no one else in the group can manifest them and they are desirable to the group in SOME way.

I also have thought in terms of a game-theoretical principle along these lines. I.e. that an organism seeks to take on behaviours which are in some sense in contrast to the dominant traits of the group they are born into. This way it can keep its genetic 'market value' while not being in direct competition with the others. But it seems paradoxical on some level. For example, how does the organism know what the optimal set of behaviours is? After all, early on, a child only communicates with its parents and is blind to what goes on in the rest of the group.

 

[Jennywocky]

Here I disagree. Even microscopic maladaptions will compound throughout generations.

But with personality type? We're not talking negative genetic mutations that impact survival, personality type just comprises general traits. Are you thinking that people who feel less anxiety in the face of closure would somehow span a string of progency that would eventually be unable to function to the point of death (before reaching an age of reproductive viability) because they need absolute closure, for example? How specifically do you think this would work with personality, which just generally impacts disposition but not survival rate?

I also have thought in terms of a game-theoretical principle along these lines. I.e. that an organism seeks to take on behaviours which are in some sense in contrast to the dominant traits of the group they are born into. This way it can keep its genetic 'market value' while not being in direct competition with the others. But it seems paradoxical on some level. For example, how does the organism know what the optimal set of behaviours is? After all, early on, a child only communicates with its parents and is blind to what goes on in the rest of the group.

I think the family structure IS the most basic structure, and the offspring are what is in competition. Parents do shape the child's behavior based on parental preferences, but those are just behavioral imprints -- you can tell because in some cases if a child has a natural disposition (for example, a quiet children) for the parents' preferences (parents who don't like loud noise or chaos), then the child will likely drop right into it without fuss, whereas a child with a naturally different disposition will end up conflicting with parents. Check out Arch's recent comments about Ti and how regardless of your personality you can absorb patterns from the parents based on upbringing (he was discussing the absorption of S patterns in non-S kids).

Let's say you have two outgoing children. The child who is more outgoing will earn more reward, overshadowing the other, if the parents are rewarding that behavior. If a different kind of child is accepted for what they can contribute that the family needs, then they will prosper; sometimes the "different" child just becomes a black sheep and is discouraged/abused, however. There's a multiplicity of interactions going on here -- the environment, the context, the genetic disposition, the family structure, the physical resources that impact development, and so on.

It's also more apparent (I think) when you have children. I've had two biological kids, and both were very different from pretty much birth and just continued to differentiate. It was clearly obvious that one was quiet, calm, observing, passive-faced; and the other was loud, energetic, engaging, and facially dynamic. It was rather amazing to witness. Those traits are still part of their makeup, even if they are far more complex now as adults.

I still get back to the reproductive aspect of evolution. Is the variance enough to prevent a child from reproducing? Looking at society, it looks to me that nowadays in a first-world country, even hugely disadvantaged people are still capable of surviving and propagating their genes. We're not talking about "survival," we're just talking about stress levels and quality of life.

 

[Haim]

Evolution is a lot more random that what commonly thought.
Who happened to survive will survive,yes statistically these that have better chance to find a mate and not die before it have more chance to reproduce but this factors have much less impact than what is thought especiale in humans where there are very little environmental conditions that limit us.
You can reproduce even if you have major disadvantage,the "the fittest will survive" is just general path of evolution and the width of that path is huge.

It a balance where every MTBI type is part of,I can't see any type that does not have some role in society as different problems and tasks need different way of thinking.
Some discovere gas,some learn to transfer it,some invent way to use it for cooking food,some cook with it,some sell it and some scream you evil corporate bastards!

 

[reckful]

I think it's likely that the MBTI preferences represent what you might call social niche strategies, and that the current percentage of N's (for example) represents some kind of optimum level of N's within the population — or at least, what used to be the optimum level, during whatever evolutionary years are responsible for the current mix.

Given enough time, evolution is a very powerful process. A genetically-caused trait that confers just a 1% reproductive advantage will, over the course of many generations and in the absence of complicating factors, gradually become a trait present in virtually every member of the population. So for example, if extraverts had been more reproductively successful than introverts for most of our evolutionary history no matter how large a percentage of the population was made up of extraverts, we would presumably all be extraverts today.

I suspect that the fact that there are substantial numbers of people on both sides of each temperament dimension suggests that, any time the percentage of the population exploiting one niche over the other becomes larger than optimal, it becomes advantageous to be a person who naturally exploits the other niche — with the result that, over time, a more or less optimal balance among the types is maintained.

Jung speculated that introversion and extraversion corresponded to competing reproductive strategies, each successful in its own way:

There are in nature two fundamentally different modes of adaptation which ensure the continued existence of the living organism. The one consists of a high rate of fertility, with low powers of defense and short duration of life for the single individual; the other consists in equipping the individual with numerous means of self-preservation plus a low fertility rate. This biological difference, it seems to me, is not merely analogous to, but the actual foundation of, our two psychological modes of adaptation. I must content myself with this broad hint. It is sufficient to note that the peculiar nature of the extravert constantly urges him to expend and propagate himself in every way, while the tendency of the introvert is to defend himself against all demands from outside, to conserve his energy by withdrawing it from objects, thereby consolidating his own position. Blake's intuition did not err when he described the two classes of men as "prolific" and "devouring." Just as, biologically, the two modes of adaptation work equally well and are successful in their own way, so too with the typical attitudes. The one achieves its end by a multiplicity of relationships, the other by a monopoly.

A June 2011 OpEd piece by Susan Cain in the New York Times described an experiment involving impulsive and cautious fish ("rovers" and "sitters"), and here's a bit of it:

We even find "introverts" in the animal kingdom, where 15 percent to 20 percent of many species are watchful, slow-to-warm-up types who stick to the sidelines (sometimes called "sitters") while the other 80 percent are "rovers" who sally forth without paying much attention to their surroundings. Sitters and rovers favor different survival strategies, which could be summed up as the sitter’s "Look before you leap" versus the rover’s inclination to "Just do it!" ...

In an illustrative experiment, David Sloan Wilson, a Binghamton evolutionary biologist, dropped metal traps into a pond of pumpkinseed sunfish. The "rover" fish couldn’t help but investigate — and were immediately caught. But the "sitter" fish stayed back, making it impossible for Professor Wilson to capture them. Had Professor Wilson’s traps posed a real threat, only the sitters would have survived. ...

Next, Professor Wilson used fishing nets to catch both types of fish; when he carried them back to his lab, he noted that the rovers quickly acclimated to their new environment and started eating a full five days earlier than their sitter brethren. In this situation, the rovers were the likely survivors. "There is no single best ... [animal] personality," Professor Wilson concludes, ... "but rather a diversity of personalities maintained by natural selection."

Cain is the author of the best-selling Quiet: The Power of Introverts, and I'd say she errs in framing the rover/sitter duality exclusively in E/I terms. The most well-established Big Five test (McCrae & Costa's NEO-PI-R) breaks Conscientiousness — i.e., J/P — down into six "facets," and one of those facets is called Deliberation. As McCrae and Costa explain: "Deliberation is the tendency to think carefully before acting. High scorers on this facet are cautious and deliberate. Low scorers are hasty and often speak or act without considering the consequences. At best, low scorers are spontaneous and able to make snap decisions when necessary." And decades of both MBTI and Big Five data have pretty clearly established that E/I and J/P are essentially independent dimensions of personality.

I'd be more inclined to suspect that the J/P dimension and the neuroticism dimension (which includes anxiety-proneness) are also meaningful contributors to the rover/sitter duality — in people, at least — but I'd also say that viewing E/I as a contributor is consistent with most MBTI sources and, in any case, I think it's probably fair to say that the most impulsive, bold, plunge-right-in types are the Calm EPs and the most cautious, look-before-you-leap, think-before-you-speak, worry-prone types are the Limbic IJs (like me).

In any case, and as a final note, there's lots of room for reasonable people to argue about both the exact nature of the major clusters of human personality variation and the causes of those clusters. But arguing that there's no such thing as substantially hardwired variations in personality, and/or that such variations would, ZOMG, be inconsistent with evolution, is just silly at this point, given the existing data. Decades of twin studies strongly suggest that genes account for around half (or more) of the kinds of relatively stable temperament dimensions measured by the MBTI and Big Five. Identical twins raised in separate households are substantially more likely to have similar personalities than less genetically similar pairs.

 

[Haim]

That's not true 99% or even 0.1% won't disappear,one genetic line,even in 10^1000 years won't mix with every single person and even if that true only fraction of the original will pass on.
Just look on how many kinds of birds,Ants,monkeys there are.
Again what happen to stick,sticks.
The "fittest survive" is just saying that if you have some advantage your quality have more chance to stick but what commonly forgotten is that there are a lot more qualities that stick anyway.
If what you say is true we would only have one specie.
That is a mistake of the nasiz,thinking thare is one best specie that should survive but the true is the earth is made of many species that happened to survive,while the more "fitted" just statistically had more chance but still there are non "fitted" species or qualities that are alive.Don't try to fit reality to theory.

 

[reckful]

That's not true 99% or even 0.1% won't disappear,one genetic line,even in 10^1000 years won't mix with every single person and even if that true only fraction of the original will pass on.
Just look on how many kinds of birds,Ants,monkeys there are.
Again what happen to stick,sticks.
The "fittest survive" is just saying that if you have some advantage your quality have more chance to stick but what commonly forgotten is that there are a lot more qualities that stick anyway.
If what you say is true we would only have one specie.
That is a mistake of the nasiz,thinking thare is one best specie that should survive but the true is the earth is made of many species that happened to survive,while the more "fitted" just statistically had more chance but still there are non "fitted" species or qualities that are alive.Don't try to fit reality to theory.

In focusing on characteristics that vary, you've apparently lost sight of the many, many, many, many characteristics (physical and psychological both) that essentially all humans share (in the absence of rare mutations).

These are characteristics that, having initially appeared, and because they conferred an incremental survival advantage, gradually became universal.

 

[Haim]

They were universal to begin with otherwise we wouldn't call them human but something else,other specie.When we evolved the other monkeys did not just die or became human.

 

[Tannhauser]

Great post, reckful.

It seems to make sense if one considers introversion/extroversion not as adaptive traits in themselves, but instead the effects of a specific choice between a long-term mating strategy and a short-term one.

 

[Inquisitor]

Most of the posts on this thread have focused on the relation between evolution, type, and the individual surviving in isolation. While that may be a valid perspective for a large number of species, it's not the correct perspective to take for humans because we are by nature tribal creatures...it's not so much the survival of the individual we should be concerned with as the survival of the tribe.

A tribe full of diverse types of individuals is going to be much more adaptable to changes in the environment than a tribe with only a few kinds of individuals. In addition, while the contributions of a single individual to the tribe may not seem relevant to the survival of the tribe at a given point in time, there may emerge a scenario where having that individual around was enough to avert catastrophe for the whole tribe.

If you need proof, just look at any large company today. The most successful ones have all kinds of different types working for them. Companies that remain attached to a single business model are going to face very significant challenges when that model no longer works.

Group survival >> individual survival

I also don't see how the OP can assert that this is not true. Social darwinism is much different from this. We're talking about smaller tribes of hunter-gatherers here, not politics/sociology. That came much later.

 

[Tannhauser]

Most of the posts on this thread have focused on the relation between evolution, type, and the individual surviving in isolation. While that may be a valid perspective for a large number of species, it's not the correct perspective to take for humans because we are by nature tribal creatures...it's not so much the survival of the individual we should be concerned with as the survival of the tribe.

A tribe full of diverse types of individuals is going to be much more adaptable to changes in the environment than a tribe with only a few kinds of individuals. In addition, while the contributions of a single individual to the tribe may not seem relevant to the survival of the tribe at a given point in time, there may emerge a scenario where having that individual around was enough to avert catastrophe for the whole tribe.

Group survival >> individual survival

I also don't see how the OP can assert that this is not true. Social darwinism is much different from this. We're talking about smaller tribes of hunter-gatherers here, not politics/sociology. That came much later.

I might have been a little bit imprecise. I was referring to the concept of group selection.

The great majority of evolutionary biologists believe (2011) that selection above the level of the individual is a special case, probably limited to the unique inheritance system (involving haplodiploidy) of the eusocial Hymenoptera such as honeybees, which encourages kin selection.

https://en.wikipedia.org/wiki/Group_selection

 

[Inquisitor]

I might have been a little bit imprecise. I was referring to the concept of group selection.

https://en.wikipedia.org/wiki/Group_selection

Then it would seem MBTI is not compatible with evolutionary theory for the moment. Personally I don't buy it b/c it goes against what I've observed in my life. I still don't see what you're getting at with this:

Considering that all the various behavioural patterns cannot have exactly the same adaptive value, how does the MBTI then, so confidently posit that the population is divided into different 'types'?

You're assuming that some types are more likely to survive than others? That's a big assumption on your part, and as far as I can tell, it's the foundation of your entire argument because from there you can extrapolate that since small differences in "survivability" (whatever that means) are magnified over time, we should not see "types" at all. How would you even test this assumption of yours to begin with? At the end of the day, when it comes to survival, what seems most probable is that the physically strongest and cleverest individuals are going to survive. Sensors tend to have a more robust constitution than intuitives, but the latter may be better in other areas mentally. We actually do see more sensors than intuitives overall, so that may be a clue.

 

[Brontosaurie]

>cool power
>control environment
>transgress consciousness
>profit

powahh

 

[ZenRaiden]

With evolution, it should be made clear that it only amounts to whether or not the offspring can live long enough to reproduce.

Long enough to reproduce and live long enough to take care of their offspring and so on... not sure what you are trying to say.

 

[buttcracker]

Maybe personality types are just random mutations that occur in every "advanced species" but are not really deciding when it comes to the survival of said species.
I can imagine that orcas can have different personalities, but those traits are not significant enough in order for evolution to wipe out one or another respectively make one personality victorious over the others.

I often wonder why certain personality traits haven't been wiped out by evolution, maybe stuff like this are just little leaps to a big thing (for a example a little less shy to a master of manipulating society), and as we follow along the steps to the big leap, we see random mutations that go forwards or backwards to that evolutionary step and wonder how is it possible that disadvantegous trait x can exist.

 

[hepiaaro]

Most of the posts on this thread have focused on the relation between evolution, type, and the individual surviving in isolation. While that may be a valid perspective for a large number of species, it's not the correct perspective to take for humans because we are by nature tribal creatures...it's not so much the survival of the individual we should be concerned with as the survival of the tribe.

Group survival >> individual survival

I also don't see how the OP can assert that this is not true. Social darwinism is much different from this. We're talking about smaller tribes of hunter-gatherers here, not politics/sociology. That came much later.

There is an article by Steven Pinker that illuminates the reasons that "groupishness" is not necessarily evidence of "group selection". I realize this sounds terribly reductionist; it is not. The article attempts to explain why natural selection from a genes-eye perspective is the best way to describe the evolution of human nature and conflicts facing humanity today.

Here: http://edge.org/conversation/the-false-allure-of-group-selection

I would be interested to know how you think group selection might emerge out of selection of the individual genes. Systems theory is probably the most appropriate language to build a description in this instance.

 

[EvilBlitz]

It is beneficial to have a diversified range of types. There is always a cost to any choice.
The black plague that led to greater resistance to disease for many Europeans conversely made them more susceptible to fungal infection.
Iron is necessary for blood platelets and carrying oxygen, but most infections feed off iron(esp Malaria) and low iron counts are a defense against infection.
Any trait is only an advantage for that particular situation.(Tall skinny Ethiopians for heat dissipation are not going to fare as well as short stocky Inuit for heat conservation in each others respective climates)

Thinking one trait is always superior is bizarre. When evolution has evolved to super specialization, they are the most susceptible to going extinct. Humans are master generalists, and considering the vast array of environments, cultures, food, societal structures and migration events, there will always be vast variance. Africans have more genetic variance than all other "races" combined, which makes a mockery of any idea of convergence.(The only real convergence if one at all exists is the decline in the number of different male lineage contributions to the gene pool with the advent of farming).

MBTI possibly fits to Parieto-Frontal integration theory(Basically intelligence is a result of executive functions and sensory perception).
How does this fit in with evolution? An example, Se/ Ne(even the pattern Ne created in Nardi EEG scans looks like a random walk pattern) would be most associated with the ADHD trait, more common in hunter-gatherer societies. A levy walk search strategy for food common in organisms(that gets internalized and scaled to the entire brain for problem solving in Ne). I have more ideas here. They need more work/structuring(Architect I would be interested in your help/opinions especially.)

Genes and environment are a loop(in both directions), asking which is more important is like asking which part of circle is more important.(You could possibly argue environment since the conditions have to be right for genes to exist/survive at all.)

 

[Haim]

It was not like there were sometime one type and then MTBI evolution came,it is just the way the brain came to work.
I think that MTBI source is the way parts of the brain transfer information types between them and from the outside to the brain and that this was "decided" in the steps when the brain form(not even mostly genetic decided).
By information types I mean visual,sound,touch,feelings and other internal representation of data,the way the brain speak to himself.
Therefore I claim that the all view is wrong and the existence of MTBI way of thinking is not because of benefit but happened to be(which is my view on evolution) as this happen to be the way the brain works.
As the existence of MTBI does not kill you,it happened to survive.
even if 99% die of some disease there is 1% that do survive,they do not go existent the same thing can be said of genetic traits,the common view of evolution is on the 99% but people don't see the 1%(and it is much more than 1% most times)

 

[Haim]

"The fittest survive" is backward and has logically error.
The fittest survive
The average fit have average chance to survive.
The unfit have less chance to survive.

Don't ignore the unfit he can survive,he is not doomed,he survived and became a wonderful new specie.
The survivor is the fittest is the true reality.
As fit is determined by if one survive or not,the "The fittest survive" has a circle definition,"the best team win" for example is also backward,if they would not win they would not be considered the best team,the win caused them to be the best team,it almost a meaningless type of sentence like chicken and egg(ignore if there is actually an answer to that).
there are many environments(like human) where the fit has almost the same chance of survival as the unfit.

 

[scorpiomover]

Let us consider MBTI in light of the theory of evolution.

Whether or not personality traits are a result of genetics or the environment or a combination, the genes of an individual are still deciding what kind of personality an individual is predisposed to.

If, for example, having an asocial personality would be maladaptive, genes which predispose for asocial behaviour would become weeded out.

Not completely. Consider the animal kingdom. Some species clearly evolved to proliferate more than others. Yet, quite often, the less advantaged species is still around, just in lesser numbers.

Considering that all the various behavioural patterns cannot have exactly the same adaptive value, how does the MBTI then, so confidently posit that the population is divided into different 'types'?

If one proposes that it is beneficial to a group of humans to have a diversified range of types,

Consider the humble carrot. Carrots grown in crop rotations with a series of other vegetables, can keep growing century after century. Intensive farming, which only grows one crop continuously (in this case, carrots), turns the land into becoming completely unable to grow anything in a matter of decades. The reason is simple: the ecology is designed in a cycle: what one discards as waste, another species eats as food, and so on. As long as one has enough species to make a complete cycle of the chain of waste to nutrients, then the chain can continue almost limitlessly. If, however, the chain does not complete in a cycle, or only has one link, then the waste builds up and up, the nutrients required are extracted more and more, until eventually, all the required nutrients are gone, and the waste has built up so much, and become so concentrated, that the soil no longer has a pH range or other conditions for growing anything.

this goes exactly under the theory of social Darwinism

Social Darwinism is a modern name given to various theories of society that emerged in the United Kingdom, North America, and Western Europe in the 1870s, which claim to apply biological concepts of natural selection and survival of the fittest to sociology and politics.[1][2] Economically, social Darwinists argue that the strong should see their wealth and power increase while the weak should see their wealth and power decrease. Different social Darwinists have differing views about which groups of people are considered to be the strong and which groups of people are considered to be the weak, and they also hold different opinions about the precise mechanism that should be used to reward strength and punish weakness. Many such views stress competition between individuals in laissez-faire capitalism,

Social Darwinism is concerned with competition between different groups that act as if they were one body. Usually, social darwinists also argue that those within their own group that do not measure up, should also be discarded. So it's really a form of individual selection.

(i.e. the theory that evolution selects for groups rather than individuals),

This is called group selection, like when taxpayers pay for scientists to study science all day, so that some of them will invent cures for diseases which will benefit all of us. It's an alternative to Social Darwinism and individual selection.

which has shown to be incompatible with the theory of evolution.

On a cellular level, unicellular organisms evolved via individual selection, while multicellular organisms evolved via group selection. In multi-cellular organisms, each cell does tasks for the good of the whole group, rather than the individual cells. Some cells, like phagocytes, commit suicide for the good of the group. When an infection strikes, the phagocytes swallow one of the germs, and then implode, killing the germs before they've had a chance to reproduce and spread further. The existence of an estimated 10 million different species of multi-cellular organisms, that evolved from a world with only single-celled organisms, suggests that multi-cellular organisms must have had a significant advantage over single-celled organisms, to not become extinct in the face of so many more single-celled organisms and when they were the dominant forms on the planet.

So it's very clear to me, that group selection is clearly very compatible with the theory of evolution. It's just not talked about much, because it wasn't what Darwin focussed on.

So it seems that either, there is no such thing as 'types' -- instead there are just temporary behavioural habits which can change if you are forced to, or: MBTI is correct and the theory of evolution is wrong.

Or, that both work together much better than one would imagine.

Consider the INTP. Not very ambitious. Often with his head in the clouds. Poor at social skills. Not practical. Hardly likely to succeed. In previous centuries, people like that would have ended up caught in the rain and caught the flu, which often led to dying of influenza or penumonia or not earned a living, and died of starvation. Certainly people like that would have found it extremely hard to get married and have children. Heavy evolutionary pressure to become extinct. We'd expect that there should be very, very, very few of them.

Yet, they are 3%-6% of the world population, something like 210 million to 420 million. OTOH, when we see what INTPs like those at Bell Labs discovered, the benefits of having INTPs around is astounding for any large group of people, just not so much for a small group, who need practical all-rounders. Thus, evolution must be driving INTPs to be so numerous due to group selection.