After someone learns about Myers-Briggs® types and starts taking online tests, one question that often comes up is how to tell the difference between two similar types. Maybe the tests you took gave you a couple different results. Or maybe you started reading about the types and discovered more than one sounds a lot like you. If you’re trying to decide whether you’re more of an INFJ or an INTJ type, I hope this article will help.

I’m an INFJ and my sister is an INTJ, and we’re both fairly typical examples of our types. Looking at the two of us it’d be almost impossible not to tell the difference between our personalities. But there’s also a huge amount of similarities between our two types — especially for what’s going on inside our heads and also how we respond to stress.

Just looking at the names of these personality types, we might think that the only difference is that one’s a Thinking type and the other Feeling. That’s true, but it’s not the full story. When we dive deeper into the cognitive functions that describe the mental processes each Myers-Briggs® type uses, it becomes easier to see the differences and similarities between these types more clearly. If you’re not familiar with cognitive functions, click here to read “The Simplest Guide to Myers-Briggs® Functions Ever.” INFJ and INTJ share the same Intuitive and Sensing functions, but have different Thinking and Feeling functions, as shown in this graphic:

The way these cognitive functions work together makes INFJs and INTJs very different in certain ways and very similar in others. The two types can often find lots of common ground and make great friends. And there are also several key differences in how they approach the world that makes it possible for us to tell them apart.

They see the world similarly

INFJs and INTJs both lead with the same function. It’s introverted, so that means these types are oriented to the inner world as the one that’s most real. It’s also Intuitive, which means INFJs and INTJs are actually dominant perceiving types even through there’s a J in the name (the J/P preference describes how someone relates to the outer world, so for introverts that’s the co-pilot function. Their dominant inner-world function is the opposite).

• If you’re an INFJ or an INTJ, spending time in the inner world energizes you. You tend to approach life from a thoughtful, introspective place. Isabel Myers said introverts, “Cannot live life until they understand it.” You make sense of the outer world by first looking inside yourself.
• You’ll typically find that your Intuitive side is the one that feels most comfortable. Pattern-recognition, big-picture thinking, and seeing things from multiple perspectives come naturally to you. You probably place a higher value on experiencing and understanding life than on controlling it (at least internally).

Because the primary function is your favorite, if you’re either an INTJ or INFJ it’s easy to identify with descriptions of both types. This is even more true if you haven’t spent much time developing the extroverted side of your personality.

They have different co-pilots

The main difference between INFJs and INTJs lies in how they use their Thinking and Feeling functions. Their co-pilot functions are the ones they use most reliably when interacting with the external world. You might actually find that the people closest to you have a clearer idea of whether you’re an INTJ or an INFJ than you do, since they see more of your extroverted side than of your introverted side.

• If you’re an INFJ, you support your Intuition with a Feeling side that helps you relate to the outer world and made decisions based on specific, personal criteria. You probably notice it most when decision-making or trying to relate to other people, because it helps you figure out how social groups work and make decisions that will meet everyone’s needs. It’s not your most comfortable process, but you can get really good at using Extroverted Feeling if you take the time to grow and develop it.
• If you’re an INTJ, you support your Intuition with a Thinking side that helps you relate to the outer world and made decisions based on general, impersonal criteria. You probably notice it most when weighing impersonal criteria for decision-making, working with facts and data, or finding ways to explain your thought processes to other people. It’s not your most comfortable process, but you can get really good at using Extroverted Thinking if you take the time to grow and develop it.

What happens in the loop

None of us exclusively use only Thinking or Feeling, though. INFJs also have a Thinking side, and INTJs also have a Feeling side. And sometimes, an INFJ or INTJ will find that side more comfortable than their extroverted co-pilot. This can make it difficult for us to decide whether we’re really more of a Thinking or a Feeling type.

Our co-pilot process is not oriented the same way as our primary process (i.e. it’s extroverted for introverts and introverted for extroverts). Because we tend to be more comfortable with processes that work in our preferred world we often bypass our co-pilot process and try to use our tertiary process instead. This is called a “loop,” and here’s what it looks like for INFJs and INTJs:

• If you’re an INFJ, you have Introverted Thinking as your tertiary. When you get into a “loop,” you become more analytical and focused on trying to organize things logically. You might become fascinated by certain topics and spend hours researching everything about them. If you spend too much time in this loop you may loose touch with your more diplomatic, relational side. This can lead to withdrawing from people and becoming more critical and defensive.
• If you’re an INTJ, you have Introverted Feeling as your tertiary. When you get into a “loop,” you become more preoccupied with your personal value system. You might even find yourself making decisions based on your emotions. If you spend too much time in this loop you may loose touch with your more logical side. This can lead to becoming withdrawn, self-righteous, and hypercritical of other’s values and beliefs.

How you are under stress

The inferior function (the lowest on a four-function stack) typically shows up when we’re stressed. You might also use it to take a break and relax, and it often shows up in our favorite hobbies. For both INFJs and INTJs, this function is Extroverted Sensing. Our tertiary function can also play a role in how we respond to stress.

• Stress often brings out your inferior Extroverted Sensing. When stressed-out, INTJs and INFJs can become obsessively focused on external data, overindulge in sensory pleasures (food, drink, shopping, etc), and develop a suspicious, hostile attitude toward the outer world. You can also use this function in a healthy way, and you might find that you enjoy activities that require sensory engagement (like gardening, cooking, yoga, or kayaking).
• A stressed INTJ may also notice certain Introverted Feeling traits, such as being excessively concerned with their personal values about what’s right and wrong. In stressful/emergency situations, an INTJ may find themselves struggling to make decisions because it feels as if their typical impersonal logic isn’t accessible.
• A stressed INFJ may also notice certain Introverted Thinking traits, such as a need to be extra precise and logical. In stressful/emergency situations, an INFJ may find themselves thrown into a “logic mode” that makes it easier than usual for them to take charge and make quick decisions.

Putting This All Together

Researching functions gives you a much more in-depth look into how each personality types’s mind works. But the functions don’t work in silos; they interact with each other and come together to help create our whole personality.

• For INFJs, using their functions together means they still lead with Introverted Intuition but it is heavily influenced by Extroverted Feeling and supported by Introverted Thinking. As they mature, INFJs learn to rely on Extroverted Feeling to make decisions relating to the outer world while also using their Intuition to help make sense of the information they gather about other people. With healthy Introverted Thinking, they can start to shift out of people-pleasing mode and become more comfortable pointing out other’s inconsistencies in logic (though usually in a diplomatic way).
• For INTJs, using their functions together means they still lead with Introverted Intuition but it is heavily influenced by Extroverted Thinking and supported by Introverted Feeling. As they mature, INFJs learn to rely on Extroverted Thinking to make decisions relating to the outer world while also using their Intuition to put together the patterns they gather from outer-world data. As they mature, INTJs can learn to integrate Introverted Feeling to soften their typical blunt efficiency and become more comfortable acting on and expressing their personal value system.

Before you go …

Don’t worry too much about trying to fit into one personality type perfectly. You’ll often find elements of yourself in several type descriptions, and that’s okay. What you’re looking for is your “best fit type,” not necessarily one that matches exactly. Also keep in mind that there is plenty of room for individual variation within a type. Myers-Briggs® simply describes how your mind works; it doesn’t tell you everything about yourself.

• If you’d like to know more about the INFJ personality type, check out my book The INFJ Handbook. I’ve updated it with a ton of new information and resources. You can purchase it in ebook or paperback by clicking this link.

What do you think? Did this article help you narrow-down which personality type you are? Share your thoughts in the comments!

 

Featured image credit: Robin Higgins via Pixabay