Twins & Personality. | INFJ Forum

Twins & Personality.

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Jan 17, 2010
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I thought this would make for an interesting discussion. Anyone have any thoughts or theories on twins and personalities? Identical v. Fraternal? Most likely differences in MBTI?

just curious to hear ideas & thoughts.
 
I thought this would make for an interesting discussion. Anyone have any thoughts or theories on twins and personalities? Identical v. Fraternal? Most likely differences in MBTI?

just curious to hear ideas & thoughts.

IIRC, I once read a excerpt from a book that stated that identical twins typically share the same preferences except for the thinking/feeling function. So, by that thought, INFJ and INTJ identical twins would be a possible example of that and if I remember correctly, I do believe some youtube videos are actually in existence that shows that example; a INFJ and INTJ female identical twins.

I think fraternal twins can be similar but they can also be very different.

Possible problems and thoughts:

Personality = Partially genetic/Up bringing.

How do we differentiate between that.

"True MBTI" type.
 
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Good call Reon. Me and my sister are fraternal twins, but we are INFJ INTJ. This would mean we were both introverted intuitives in our formative years, and then took a preference for feeling/thinking a bit later in life. If you look at the personality page's section on children, they leave out the third function when they are typing kids. So children up to 13 can be typed as INJs. This made sense to me, because my sister and I must have seemed very similar to start with, and started diverging at maybe aged 8 or 9.
 
Good call Reon. Me and my sister are fraternal twins, but we are INFJ INTJ. This would mean we were both introverted intuitives in our formative years, and then took a preference for feeling/thinking a bit later in life. If you look at the personality page's section on children, they leave out the third function when they are typing kids. So children up to 13 can be typed as INJs. This made sense to me, because my sister and I must have seemed very similar to start with, and started diverging at maybe aged 8 or 9.

Actually, they're leaving out all but the first function. INJs are Ni dominant. The assumption is that the secondary function doesn't truly start to develop until the teenage years, and the tertiary until the 20s and the inferior until the 30s.

Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.
 
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Actually, they're leaving out all but the first function. INJs are Ni dominant. The assumption is that the secondary function doesn't truly start to develop until the teenage years, and the tertiary until the 20s and the inferior until the 30s.

Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.

Gloomy would be good too (INFJ/ENTJ twins), but she isn't around anymore.
 
Actually, they're leaving out all but the first function. INJs are Ni dominant. The assumption is that the secondary function doesn't truly start to develop until the teenage years, and the tertiary until the 20s and the inferior until the 30s.

Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.
i am one as well, which is part of why i asked
 
Actually, they're leaving out all but the first function. INJs are Ni dominant. The assumption is that the secondary function doesn't truly start to develop until the teenage years, and the tertiary until the 20s and the inferior until the 30s.

Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.


Ok, this makes sense. Individuation and functions have never particularly interested me! The fact remains, INFJ INTJ might be a common twin thing, it's true of us. And other twins I know. Although I do know one set of identical twins who were introvert/ extravert.
 
My brother and I are half-identical or identical twins.
My brother is INTJ. I am INFJ.

I think the T/F split holds a lot of truth. When my brother and I were growing up there was a strong tendency to vie for both connectedness and independence, with a tendency for my parents to pick up on and exaggerate the slightest differences between us (which WAS helpful, IMHO.)

But I remember having INFJ tendencies by the First grade, so the forced T/F differentiation would have to take place rather early, before a lot of conscious differentiation is made by the twins, but not before parents start to impose differentiation.

I wonder if this is a natural proclivity, or 'elbow room' issue, or parental influence, or a combination of these.

Any handedness differentiation between the twins here and there T/F leaning? I'm ambidextrous/left leaning, my brother is strictly right handed.
 
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yes, i am a lefty and my identical twin is right-handed, ecton
 
Actually, they're leaving out all but the first function. INJs are Ni dominant. The assumption is that the secondary function doesn't truly start to develop until the teenage years, and the tertiary until the 20s and the inferior until the 30s.

Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.
We need all four conscious functions just to make sense of reality, learn, survive, and interact with the world. As soon as we leave the womb we need to start doing all of the above right from the get go, so it actually makes more sense that we already have our cognitive function hierarchy set in place at birth. Nobody actually uses isolated cognitive functions either, so if you have a dominant function then you must have an auxiliary function connected to it. We would not be able to survive or even experience with only Ni or only Ti, because we would have no way of engaging the external world. On top of that, if those two functions are in place we would need to have our bottom two functions on the opposite side of the brain to balance ourselves out.

The functions don't exactly start out "developed" but their wiring and hierarchy starts out already in place, and then from there they begin developing. Much like how our muscles are not developed at birth, but they are already in place with the potential to develop with experience and exercise.

Also, cognitive functions do not develop at any specific ages, it all depends on your environment and upbringing. A thinking heavy household will validate the growth of a thinking function, even if it is only a Tertiary, and might even suppress other cognitive functions such as feeling; if said function is being invalidated by their environment. It is possible to have very well developed lower functions at young ages.
For instance, my niece is an INFJ, she is 11 years old and can use Ti at even more advanced levels than most 20 year old INFJs I have seen.
 
My brother and I are identical ENFJ twins
He is gay, i'm straight
He is left-handed, i'm right handed
It would seem I have more of an affinity for fixing things (like bikes and such)
he is definitely neater and somewhat more organized than I am

don't know what really to take from this, just throwing the info out there
 
my twin i think is INT. not sure about P or J though. still trying to work on that. though he tests as ISTJ
 
my twin i think is INT. not sure about P or J though. still trying to work on that. though he tests as ISTJ
Hmmm, sometimes INTPs with not-so-well-developed Ne test as ISTJ.

Have you noticed any particular function he is using for his worldview? Specifically Ni or Si? Or I suppose, it would be more accurate to watch if he is using Ti or not? Does he make clarifications in correcting logical consistency, but not actually push his worldview or perceptions of what is true? Another way to put that is: does he focus more on telling people what is true, as opposed to correcting other people's perceptions of what is true?
 
Hmmm, sometimes INTPs with not-so-well-developed Ne test as ISTJ.

Have you noticed any particular function he is using for his worldview? Specifically Ni or Si? Or I suppose, it would be more accurate to watch if he is using Ti or not? Does he make clarifications in correcting logical consistency, but not actually push his worldview or perceptions of what is true? Another way to put that is: does he focus more on telling people what is true, as opposed to correcting other people's perceptions of what is true?
those two do seem very similar, almost overlapping. So granted he does both, but honestly im still trying to sort out the differences in the two ideas you just said. I know he has an amazing memory recall, which would indicate high Si, but im not sure if it's his dominant function.He seems less pratical than an N, but he also seems to not be concerned with implementing a design or an idea as much as an INTJ would be i think. I have serious doubts he is an Ni dom anyway, but i can't say for certain.
ISTJ and INTP are so different though, so why am i getting so hung up on that? i don't think his self perception on the MBTI is as accurate as it could be though. and im not going to rule out the possibility of INTJ either, as he does seem to have some strong J traits
 
Laurie would be the expert here. She has an identical twin. Laurie is an INFJ. Her sister is an INTP.
Well, now she's not sure ^^" she's thinking she's an ENFP.

I think that usually there's one twin that's more outgoing and the other is more shy - It could work in both introverted and both extroverted twins too. I've met a couple of identical twin pairs (There were 3 including me and my sis in our school year) and there's always one that's more talkative. It must be a balancing thing ^^"
 
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