How to tell if you are INTJ or ISTJ

Many ISTJs test as INTJ, whereas the opposite phenomenon seems to be less common. So a rule of thumb is that if someone tests as INTJ but is in doubt about whether they might be an ISTJ, then it is probably (but by no means always) the case that they are an ISTJ.

What follows is an illustrative exchange between two I-TJs about their type self-discovery processes.


I have tested both INTJ and ISTJ in the past and I feel like parts of both descriptions fit me. I am an extremely strong I, a strong T, a fairly strong J, and a huge question mark on the N/S.

I noticed in the introductions post that a few people have tested as both INTJ and ISTJ but they felt the ISTJ description suited them better. So, what was it about the ISTJ description that you felt fit you better?


It was a while ago that I explored the two types in comparison to myself, so let me quote from the wikipedia page on the N/S difference:

Sensing and intuition are the information-gathering (perceiving) functions. They describe how new information is understood and interpreted. Individuals who prefer sensing are more likely to trust information that is in the present, tangible, and concrete: that is, information that can be understood by the five senses. They tend to distrust hunches, which seem to come “out of nowhere”.[1]:2 They prefer to look for details and facts. For them, the meaning is in the data. On the other hand, those who prefer intuition tend to trust information that is more abstract or theoretical, that can be associated with other information (either remembered or discovered by seeking a wider context or pattern). They may be more interested in future possibilities. For them, the meaning is in the underlying theory and principles which are manifested in the data.

Obviously we all use both sensing and intuition, but for me the sensing mode is much more dominant. I’m all about details and concrete reality. I had to study a lot of philosophy in college, and it was some of the most difficult and painful courses I’ve ever had. Chemistry equations and statistical analysis? No problem. Discussing the transcendental properties of being? Problem.

I still have hunches, and unlike the quote I will trust them… I’ll just look to verify the hunch as I go. For example, gaining some insight into my life during prayer is not uncommon, and I’ll take it for what it is, but the rest of the week I’ll keep thinking over the insight from every angle I can.

When I first took the Myers-Briggs, I had never thought about how I take in information. I think that was why I tested so indifferent, I didn’t have the knowledge and self-reflection to answer consistently with my real preference.

…I do remember when exploring the types a difference being that memories for an ISTJ is more about sense information (visuals, sights, sounds) and for an INTJ it is more the conceptual (what, who, why). At first I felt like I was both, but after observing my memories for a few months, I think the ISTJ is more “me”. I’ll remember the sense detail first, and then in a split-second use that to remember the conceptual things.

Other than all that, the dedication and responsibility of the ISTJ is definitely me.


Hey, great reply. I’m still confused about my S/N tendencies, though. I really think I am just an IxTJ but I lean towards S, probably.

What do you think would be college courses that an N would enjoy/excel at compared to an S? My favorite classes were English literature, history, government & economics – courses that involved not only acquiring facts, but also being able to compare/contrast different theories, imagine different interpretations of events, etc.

I’m a pharmacist and I truly enjoy my job and I feel that it suits my personality very well. It is a very black & white evidence-based field and I have to keep tons of factoids in my working memory. (I do particularly like psychopharmacology which is rather less black & white than say, cardiovascular pharmacology.)

I do feel that I am a fairly intuitive person and I always felt that I would just “get” concepts while I was in pharmacy school and I could often effortlessly see how concepts fit together. This meant that I could get away with not studying as much as my classmates sometimes. :) However, I find topics that are purely abstract or theoretical boring and not really worth my time or effort. I would rather that things have a practical application.

Interesting about the memories. I would say that my memories tend to be very visual, like a snapshot (like from a 3rd person viewpoint, even). Often I have lost a lot of the details surrounding the snapshot – like, I can’t remember why was I there? Who was I with other than the people in the image? That is probably more of a S sort of memory experience, right?


It could be that you are really IxTJ… keep reading about both types and give it some time. The trap of Myers-Briggs is to force ourselves into a category, when really the types just give a general framework to as many personalities as there are people. If you ask me, it’s a very helpful framework, but it is no subsitute to knowing someone, ourselves first and foremost.

What do you think would be college courses that an N would enjoy/excel at compared to an S?

Probably anything that favors theory over application, but I also think it largely depends on the professor and how they approach the subject. A course might be highly focused on theory instead of application, but if the professor starts with examples and then unfolds the theory, I think an N would have a harder go at it. On the other hand, a course focused on application but that introduces everything with theory first might be natural to the N.

That is probably more of a S sort of memory experience, right?

Sounds like it, according to my understanding. Obviously all memory is sensate to some degree, but I think the persistent preference to sense data over other data is indicative of S… for the S conclusions are drawn from sense data and then applied to a larger theory, for the N it seems that conclusions are drawn in theory and then applied to sense data.


  1. Is there a corresponding phenomena for ISFJ’s?

    I think that quite a few people want to have an N because the N types are typically viewed as more desirable or even superior, since they are both rarer (and, hence “unique”) and on average score higher on IQ tests.

    Thus they may conciously or unconciously answer incorrectly, or overrate their aptitude for theory on tests or redo the tests until they get their desired N result.

  2. In our experience, yes: There is indeed a corresponding trend for ISFJ / INFJ. And likewise for ISFP / INFP.

    Besides the excellent conjectures that you offer, it does not help that many portraits are skewed in favor of the N’s as well.

  3. I like Keirsey’s model a lot and in that one an ISTJ would be an SJ Guardian type while the INTJ would be an NT Rational type. Therefore, the ISTJ would be far more conventional and traditional and unwilling to question social norms, while the INTJ would be freethinking and quite willing to challenge the status quo.

    So coming at it from that angle might help differentiate, as well.

  4. In terms of cognitive processes, it seems as though introverted sensing types trust completely their own personal experiences as fundamental truth, applicable to all.

    An ISJ relative of mine indignantly expressed to me that there was only way one to boil an egg, and then proceeded to explain to me all of the steps necessary. It had never occurred to them that there were alternatives(Ne?), and the mere thought of these alternatives nearly gave them hives.

    Conversely, this person is also capable of providing alternative solutions when people around them seem to be in need of problem solving.

    Ni types can be just as indignant about what they perceive in their minds, but not so much so about their own personal experiences being universal truth; and the specifics of how one folds a towel or washes a dish or even solves a mathematical equation seem to belong solely in the Si camp.

  5. INTJ Writer’s comment “I like Keirsey’s model a lot and in that one an ISTJ would be an SJ Guardian type while the INTJ would be an NT Rational type. Therefore, the ISTJ would be far more conventional and traditional and unwilling to question social norms, while the INTJ would be freethinking and quite willing to challenge the status quo.”

    I am unsure about the IxTJ. I am equally liking strong in both N/S, however INTJ Writer’s comment did it form. I am a rebellious, freethinking and yes I am willing to challenge the status quo (I don’t like the idea of groupthink). I think I’m always a bit of a chameleon. Everyone sees me as E instead of I but I personally feel like I am an I but I can be both. Naturally I like silence and quiet over noise, socializing. So thank you INTJ Writer – you answered it for me.

  6. My issue is that when there is a bit of friction between type decision (I’m currently bound between INFJ/ISFJ)

    What counts as “evidence” becomes a highly volatile scenario. Of course, the question to ask is “what” the questioning person looks to “As” evidence, I would assume.

    In my case, the issue is that I vacillate- simply put. I find a slew of characteristics that jives with my concept of self and then it’s uprooted and I have a barren seedplot again. Then we go up once more- either with the same plant (oh look, INFJ) or a different one (hey… ISFJ). I will be the first to admit that I was influenced by the stereotypes of INFJ/ISFJ as rife on the internet forums of today (spurious resources indeed!)

    But when it comes to the ACTUAL theory here, I am at a slight loss for militarized thought. I keep on going nowhere, which is not what I am interested in doing (though this could be indicative of type- I have no idea what!)

    I am quite the opposite of Adam academically (bad at chemistry, loved philosophy) ALTHOUGH I am always wary that the age I live in has such atrophied standards that any self-judgment according to external criteria such as whether or not I loved a “theoretical” course or not is not going to fly well in the real world of cognitive functions.

    Perhaps this is indicative of a lack of “abstract” certainty? OR a perspective that is abstract that I’m indeed holding that is running into some neurotic conflict related to my self-image (apologies for butchering of terminology if there are any).

    Though- I am aware of my conflict in accepting the ISFJ pill or diagnosis, even though the typing would not change who I am inherently- merely my self-approximation (and there we got some cool stuff for thought. Unless I’m preaching to the choir)

    ANYWAY. This blog post from Ctypes was somehow insightful in a weird way, though the first sentence about ‘doubting INFJ = ISFJ (even if not in all cases)’ worried me. IDeally, finding my type should be independent of concerns not related to the body of psychological theory built into it. Anyway… What a boring post this must be to read! I thank you all in advance if you happen to chance upon it.

  7. I’m an INTJ who occasionally gets an ISTJ result, always in the unofficial not-really-the-MBTI online versions of the questionnaire. SOme of the describpiot matches (well, duh, ITJ!) but the full description and the Temperaments aspect (Keirsey, mentioned by INTJ Writer) tell me all I need to know.

    No Guardian type here. No Duty fullfiller. Rules? We don’t need your “rules”. the dedication and responsibility of the ISTJ is soooo definitely not me.

    Oh, and according to MBTI / Jung Type theory, there is no ‘x’. You just haven’t worked out your core preference yet.

  8. When I took the M-B test, I was an ISTJ, and when I took it again, I was an INTJ. I don’t like uncertainties, like when my JROTC instructor tells me to do something, but I don’t understand it. However, I do like classes with theoretical principles, like Algebra, because they make sense to me. I looked up the personality types of the people with ISTJ and INTJ and I feel that I am both a duty fulfill-er and a scientist. Can any of you guys help me with this? I’m trying to use this to figure out what types of careers would be good for me to pursue. Thanks.

  9. @Chrissy:
    If you’re still confused, it might be helpful to take a step away from the Keirsey model and examine the Jungian cognitive functions it derives from.

    Ti= Introverted Thinking Fi= Introverted Feeling Si= Introverted Sensing Ni= Introverted iNtuition Te= Extraverted Thinking Fe= Extraverted Feeling Se= Extraverted Sensing Ne= Extraverted iNtuition

    The ISTJ functions are Si-Te-Fi-Ne while the INTJ functions are Ni-Te-Fi-Se. Since you are trying to decide whether you are S or N, we know that you have Te-Fi in the middle. We need to figure out whether you use Ni first and Se last (INTJ) or Si first and Ne last (ISTJ).

    You mentioned that you don’t like uncertainties, which sounds like a J-type characteristic to me since J’s extravert their top Judging function (in your case, Extraverted Thinking, or Te). You also said that you like classes with theoretical principles, like Algebra, because they make sense to you. In what way do they make sense to you? If the system makes sense to you, that could be your Te. If it’s the abstractness of the theoretical classes, then that could be Introverted iNtuition talking, making you an INTJ.

    I’m not in any way, shape, or form an expert on this stuff, but if you have any questions on the functions, how the 4-letter code (e.g. ISTJ) is derived from them, and how they work in individuals/real life, you can ask away, and I’ll answer them to the best of my ability or post some links. More input on you would be preferable, though. As in, how your mind works rather than the behaviors you exhibit.

    Here is a link to a type comparison tool based on the functions=
    In fact, on that site, you can take a test based on the cognitive functions and how they work together in a type rather instead of one based on the M-B preferences (I, E, N, S, F, T, P, J). It’s still being fine-tuned, but I think it’s a pretty good quiz. Actually, that site talks about the functions and stuff on it, so you should be pretty well set.

    Sorry about that brain dump. :3 Good luck on your typing quest. I hope this helps you with thinking about careers.

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