If you are not familiar with Jungian cognitive functions, please reference “Personality Development Tools: The Car Model” to familiarize yourself with cognitive functions and how they influence personality type.

If you want support in figuring out your best fit type – we have professional profilers that can work with you to discover how your mind is wired.
Find out more about Personality Type Consultations here.

personalityhacker_between-two-typesIf you can’t figure out your personality type, it doesn’t matter which personality psychology system you’re using – you’re stuck. We all understand typology systems based on how we fit into them.

It’s incredibly frustrating to read two, three, four different type descriptions and know you’re ALMOST there.

For some people it becomes a Chinese finger puzzle that has to be solved, and they pour countless hours into reading type descriptions from what feels like a million websites and sources.

By the time I get an email, the people who write me have generally parsed their type down to two contenders in the Myers-Briggs system.

I’ve noticed that there are a couple of predictable patterns in the battle between The Final Two in Myers-Briggs. Understanding these patterns can help narrow down to your Best-Fit Type.

Your Best-Fit Type is the personality type you resonate with the strongest and which you have “self-typed.” A profiler can help guide you toward your Best-Fit Type, but it is ultimately YOU that determines your type. And while people can (and do!) latch onto a type that serves their biases, each individual gets to make the ‘final call’. After all, you’re the only person that dwells inside your head and knows the terrain better than anyone else.

A caution: Attaching to a type based on how you want to see yourself only limits personal growth. The most helpful quality to develop in self-typing is modesty, the ability to honestly assess what you’re great at as well as owning your limitations.

First, let’s talk about the most common Final Two (in my experience, based on email inquiries):









Notice that almost all of the inquiries are from people questioning which Intuitive type they are, or at least asking if they might be Intuitive.

While any and all of the 16 types can become interested in and even obsessed with the system, it’s generally Intuitives that take it Very. Seriously. The Myers-Briggs system offers Intuitives an explanation for that life-long feeling of being a ‘weirdo’ or ‘alien’, confirming what they suspected the whole time: they don’t think like the majority of people. Great relief also comes from understanding they’re not alone, and in fact up to 25% of the population has similar enough wiring to feel a sense of simpatico. For someone who feels like an outcast, this can be game changing information.

Both the INFJ/INFP and INTJ/INTP questions warrant their own attention, so I won’t be diving into them in this article. They also don’t follow the same ‘patterns of confusion’ as the other types. Confusion around INFJ/INFP and INTJ/INTP are more based on similarity of descriptions. That is, INFJs often resonate with descriptions of INFPs, and vice-versa. The same is true for INTJ/INTP.

This article will address confusion between these types:







One pattern to notice is that there is generally only one dichotomy letter that’s in confusion. They could also be written as:

INxJ – T or F?

ENxP – T or F?

ExTJ – N or S?

ExFJ – N or S?

IxTP – N or S?

IxFP – N or S?

So… what’s the connection? Where does the pattern emerge?

The answer lies in each personality type’s cognitive function ‘stack’. Each type isn’t about what you are, it’s about which cognitive functions you’re using. There are eight cognitive functions, and each personality type has four of those functions that influence them the most.

A cognitive function is a mental process we utilize to 1) learn new information and 2) make decisions based on that information. They are technically called judging functions and perceiving functions. Please don’t get them confused with personality types that are Judgers and types that are Perceivers in the Myers-Briggs system. While the same term is used in both ways – and while they are related – they refer to subtlety different aspects of type.

The technical way of referring to cognitive functions are Dominant, Auxiliary, Tertiary and Inferior.

For each type the Dominant process is their ‘go-to tool’ in their toolbox, and the mental process with which they most identify. The Auxiliary helps balance each type out by making up for anything the Dominant lacks. The Tertiary is the opposite of the Auxiliary, thus creating a ‘weakness’ that can trip the type up. The Inferior (the opposite of the Dominant) creates a real Blind Spot, arguably the weakest function of the type.

For many years, Personality Hacker has worked to simplify an understanding of cognitive functions using the metaphor of a car. Our terms are “Driver” (Dominant), “Co-Pilot” (Auxiliary), “10 Yr Old” (Tertiary) and “3 Yr Old” (Inferior).
personality-hacker_car-model-cognitive-stackThe four letters in your Myers-Briggs personality type are like a secret decoder ring to tell you what your cognitive function stack is, also known as “how your brain is wired.”

If you are an N (Intuitive), you may only have a surface understanding of how your brain is wired, because there are two types of Intuition – Extraverted Intuition and Introverted Intuition. (For a deeper dive into both types of Intuition, please refer to Personality Hacker podcast Introverted Intuition vs. Extraverted Intuition.)

The same holds true for S (Sensing) types, T (Thinker) types and F (Feeler) types. Each of these letters represents two different cognitive functions.

So, it’s not a question of “Am I a Thinker or a Feeler?” It’s a question of “Which Thinking and Feeling processes am I using, and in which order?”

It’s not what you are, it’s what you’re using.

This dials up the ‘complicated’, while at the same time creating a lot more clarity.

For those of you familiar with cognitive functions, the pattern that immediately jumps out is this: type confusion almost always dwells in the Co-Pilot and 10 Yr Old positions.

For example, when INxJs have confusion over whether or not they’re a T (Thinker) or F (Feeler), it’s because their Co-Pilot is either a thinking or feeling cognitive function, and so is the 10 Yr Old. Here’s a side-by-side look:

If you notice, both types share a Driver and 3 Yr Old process. The same pattern holds true for ENTP/ENFP:


…AND for those who have confusion around ENTJ/ESTJ, ENFJ/ESFJ, INTP/ISTP, INFP/ISFP. For example:

It’s common to recognize certain attributes shared by the Driver process, and then weigh a ‘feeling of familiarity’ with the Co-Pilot and the 10 Yr Old processes, trying to figure out which is strongest.

Since many type profiles don’t include the cognitive functions, but rather overall descriptions of how the types generally ‘show up’ in the world, the individual is left looking for something they don’t even know exists: tie-breaker examples between the Co-Pilot and 10 Yr Old cognitive functions.

But if the 10 Yr Old is a weakness and in the “backseat” of the car (so to speak), why would a type resonate with it enough to have confusion?

There’s a great model that was introduced to me years ago called the “Competency Model.” It’s designed to explain the stages in which people build skill, but I’ve found it to be a great way to understand each type’s relationship with the functions “in the car.”


Matching it up with the car model, it looks like this:

If you match these two models up, both our Co-Pilot and 10 Yr Old processes are in our ‘conscious awareness’, whereas our Driver and 3 Yr Old processes are unconscious – either due to muscle-memory style competence or blind-spot induced incompetence.

When a type profile hits us so hard we feel like someone stole a page out of our playbook it’s because we’re reading a description of our Driver process, something that’s so second nature to us it no longer has language. When someone puts language to what we are unconsciously competent at we feel like they’re reading our minds.

Similarly, when someone describes our 3 Yr Old process well we generally just get the heebie-jeebies. It’s ‘foreign’ and ‘icky’ and ‘not us at all’ (though it is ‘us’, just the part of ‘us’ we tend to bury deep in our unconscious).

But the Co-Pilot and 10 Yr Old processes are different. We’re VERY aware of them, because the yin-yang relationship they have is in our field of awareness. We’re ‘conscious’ of both of them and how they impact us, including how the polarity of these two functions impact us. If we’re a Thinker – but not Thinking Driver, Thinking Co-Pilot – we can conceivably test out as a Feeler because there IS a Feeling nature to us. Just a 10 Yr Old Feeling version.

In the same vein, if we’re an Intuitive – but not Intuitive Driver, Intuitive Co-Pilot – there will be a strong connection with the Sensory part of us, because it’s in our conscious awareness, and may have us testing out as a Sensor some of the time.

And here’s the kicker. If we’ve learned defensive strategies that keep us in the ‘attitude’ we prefer (as explained in this article), we may be more associated with our 10 Yr Old process than our Co-Pilot!

SO. If you’re down to a Final Two, the most helpful information will be 1) learning the cognitive function stack of both types, and 2) a strong description of each cognitive function.

Good luck!


p.s. Here’s a quick overview of each cognitive function and the cognitive function stack of each Myers-Briggs type.

If you want support in figuring out your best fit type – we have professional profilers that can work with you to discover how your mind is wired.
Find out more about Personality Type Consultations here.

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  • Randall lee
    • Randall lee
    • May 28, 2021 at 4:19 am

    I am so sorry but I have so much to say and I don’t know if I’m going to be able to use punctuation because I’m going to use talk to text,

    But I will pause between each breath long story short I am a walking conundrum of personality traits and everything of my 40-year life says that

    There is no question about being all eight of the key types in the personality and I would really love to know why?
    And where do I go from here because my whole life has been a abundance of conundrum circumstances where I am having conflicting powerful emotions!

    Somebody please help me figure this out and not only that is I’ve been on a spiritual awakening of the ages.

    It’s been 3 days I have never did a personality test but again I’ve been on this journey to discovering myself and was able to pinpoint everything about myself not only that come across a article that look like I wrote it word for word because I have a witness being my wife who inevitably got me to the point of the spiritual awakening.

    Please help me out I’m so Lost in the world but so understand why I tick in every way….

  • nilptr
    • nilptr
    • August 31, 2020 at 6:45 pm

    I and a good friend of mine have exactly this problem as well: I,N,P are clear for us, but we both seem to settle about halfway on T/F. All of these tests have the same defect: any questions about conflict resolution that offer alternatives between justice, fairness, any quasi-objective standard, and customizing a solution to the particular needs or desires of the people involved end up damning T-sorts as F-sorts. Even for a Ti-user, the obvious principle in solving a conflict is, whereever possible, satisfy or reconcile the actual participants’ needs. (This minimizes complaints and emotional blowback, a win for T types.) Once one chooses that approach on these questions, no matter how rigorous the logic behind the choice or the logic used in determining the outcome … zap! We become feeling sorts. T-types who’ve ever had to deal with customers have been traumatized into looking for win-win situations … :-(

  • Emily
    • Emily
    • May 24, 2020 at 12:10 pm

    Well, all these sound interesting and makes sense until I consider my own personal case. I struggle to understand why we must have our functions in the order provided by the types. For example, I took multiple tests for the functions and got Fi and Ti almost equally high. Before delving into this function theory, I took a lot of mbti tests and read a lot of articles/forum chats/videos, yet I still failed to figure out if I’m intp or infp. Even if I read articles that specifically tells the difference between the two types, I find it incredible that I recognize with exactly half of the intp traits and the other half infp traits. Why is it not possible for me to have functions of, say, Fi, Ti, Ne and Si, different from all 16 personality stacks? Is there any concrete scientific theory that explains why someone like me have to have Ne auxiliary? When I think about my close friends, it also seems they don’t behave like any of the mbti types. Is it possible for this theory to be fundamentally flawed? I know it’s been a long time since you posted this article but I still hope you can see this and clarify, thanks.

  • Jessica Abrahams
    • Jessica Abrahams
    • January 21, 2020 at 4:00 pm

    I definitely lead with “Perspectives,” but I am still stuck between INFJ and INTJ. I test as an INTJ every time, but the cerebral INFJ is something I resonate with a lot. I resonate a lot with both types. I’d love to see a podcast or article about the differences between authenticity and accuracy as tertiaries, and between harmony and effectiveness as co-pilots. Where I have a lot of confusion is that I care deeply about people, once I start respecting them, and can easily get hurt by people I care for, but I don’t care at all about people around me unless I actually respect them.

  • Dori
    • Dori
    • August 22, 2019 at 5:14 am


    First of all, I just want to give a big thank you to Antonia & Joel for all of your amazing work! I have been following you guys for a few months now and really feel that you two are the greatest voice of reason I have found doing this work.

    I first got interested in MBTI in undergrad many years ago, and initially tested as ENFJ. I spent many years in college (undergrad and grad) while working at the same time. At the time ENFJ sounded pretty accurate to me, so I took at face value and didn’t think much of it. Only in the past year did I get really interested in digging a bit deeper.

    It may sound silly but I have gone back and forth between ENFJ and ENFP- I have taken the test here a few times just to see if I’m getting consistent results and I keep typing ENFP (even after months in between). Perhaps that seems bizarre given the fact that they share none of the same functions, but I have a suspicion as to why.

    I have listened to many of your podcasts, I have read your book and have been consuming a variety of books and literature on the topic from various perspectives, and one thing I keep coming back to is how much it resonates with me when the topic of ENFP is discussed, when extroverted intuition or introverted feeling is discussed.

    My suspicion is that my tendency to test ENFJ at times is a combination of my upbringing and my career – I grew up in the south and in an area with a strong religious paradigm and, particularly with women, you were expected to act or behave in certain ways- to be “ladylike” thus conforming to those social norms was rewarded- I have to wonder if that has played out in my confusion about type. When I reflect back, I rejected the notion of acting or behaving in certain ways to be accepted, but as all humans crave love an connection, I at times would conform to get that and thus the act of “harmony” was rewarded.

    In addition to my upbringing, I am a social worker. I spend every day thinking about the needs of others. Listening to their concerns and helping them address those concerns in a way that gives them a voice- however, the more I process this the more I wonder if I’m using extroverted intuition and introverted feeling to connect with others and find possibilities or ways of helping them.

    How much of a role do you think culture can play into mistypes? And do you have any suggestions for those who feel like culture and upbringing make it difficult to sort out what is their upbringing versus what is authentically who they are at their core? I wish I was in a position to purchase a consultation, but I am not at this point, I am, however, in a position to purchase the premium profile to continue my journey of growth, and would like to be pretty certain of my type before purchasing.

    Thanks again for all that you do.

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