Analyzing and understanding one’s personality with Jungian psychology can be of great help to you on a personal or professional level. It can be an even more valuable asset on a love and relationship level. No, understanding this theory will not bring your future partner home to you, nor will it make your future relationship perfect (because that will depend solely on you). However, the theory of compatibility can help you understand which people are naturally made for you, based on the compatibility of your cognitive functions.Â
Of course, any relationship is possible; let’s never lose sight of the fact that two individuals who work equally to keep their relationship together can overcome all the challenges. However, there are individuals with whom this work will be less or almost non-existent, simply because of the compatibility of your cognitive functions.
This is the principle on which Birdy is based: to introduce you to people with whom you will have the greatest chance of creating exciting and rewarding relationships with (which can be decisive factors in your long-term happiness). There is nothing magical about this; simply the use of Jungian psychology over more than a century in understanding and strengthening the quality of human relationships.
To understand what follows, I advise you to read the article on the details of cognitive functions first, because we are now going to talk about the duos of compatibility between these functions.
First of all, there are 4 compatibility duets: Ti – Te, Fi – Fe, Si – Se, Ni – Ne.
To talk about a duo in general, we will call Xe the extroverted function and Xi the introverted function of the duo.
But why are Xe and Xi compatible?
For each compatibility duo, Xi acts as the generator, and Xe as the mediator. It is from Xi that the needs of the individual comes, and it is Xe that acts as a mediator between Xi’s needs and the world.
Quick analogy time!
In an atom, electrons gravitate around a nucleus. The nucleus is the bulk of the atom’s mass and the electrons, which are less massive and more volatile, form the interactions with other atoms. In other words, the nucleus is the heart of the atom and the electrons are the auxiliary with the outside world.
With compatible function duos, it’s basically the same thing.
Xi acts as the heart of its dimension (T, F, S or N), while Xe gravitates around it to act as an intermediary with the outside world. Xi represents the subjective potential—the cognitive needs that will have to be met—and Xe is the external response to Xi’s needs.
Xi is the source of needs, and Xe the source of answers. Xi expects Xe to pay attention and to understand and respond. And Xe expects Xi to have a need in order to be able to meet it. This concept will become a reality when you read the examples below. (Keep reading!).
Obviously, the higher the functions are used within both types, the more this model will apply. To understand the compatibility phenomenon, we will take cases where Xi and Xe are the dominant functions of two types in order to visualize compatibility at its theoretical peak.
Let’s start now with Ti – Te compatibility!
Compatibility Te – Ti
Relationships based essentially on this compatibility: xxTJ with xxTP
What Te brings to Ti
Frequent Ti users create a complex and deep world for themselves. This allows them to understand reality in its smallest details and to act in accordance with it. Unfortunately, few people will be able to understand this realm of logic. Often before having even tried, not seeing the point of asking themselves so many questions about the world and trying to find a logical explanation for everything. Almost no one, except the very frequent users of Te, will take the time to dissect this and be interested in the origins of the ideas of Ti.
Te will not only be interested in this world, but as a user who is forever interested in what others think, he/she will understand and connect with Ti the most.
Once this connection is built, Te will try to offer new perspectives for Ti, showing them theories or research in Ti’s areas of interest. This way, the world of Ti becomes even more objective and real, and both feel connected and validated.
In other words, Te will reframe Ti when the latter’s thinking is not well enough founded and make Ti find usefulness in trying to implement ideas concretely. Even if Ti holds the knowledge, it may fail to be effective because of a lack of confrontation of ideas with reality. You will be able to make sense of Ti’s theoretical knowledge by taking a step back from the reality of their ideas.
What Ti brings to Te
Te has goals and seeks the most direct way to achieve them. Its users love it when their projects run smoothly or when everything is efficient and optimized. However, they may lack patience, ability, or simply the interest in taking the time to understand things in detail or to learn how certain systems work in depth. As soon as they get to the point where they think that learning more won’t improve the results, they will stop.
That’s why they need people who are constantly trying to understand things without feeling like it’s a waste of time—cue the Ti users—a perfect match for the Te’s longing to be understood.
Ti will spend their time debating Te’s beliefs based on logical reasoning, and over time, will make Te more logical, critical, and efficient. The Ti user will act as a filter for Te’s logical errors. Te’s frustration at not being efficient will gradually disappear thanks to Ti’s advice.
Reciprocal benefits
Both have the same distance from what they say to each other, allowing for good debates in which both partners can drop all their arguments without risking injury to the other. These debates are often heated, and from the outside may appear to be real conflicts.
It is a real relief to not have to worry about hurting the other. At work, this compatibility will manifest itself through decisions that will be taken without errors of logic thanks to Ti, and without errors of subjectivity thanks to Te. This leaves room for very thoughtful and fair decisions that will have their consequences on the working efficiency of the pair.
Compatibility Fe – Fi
Relationships based essentially on this compatibility: xxFJ with xxFP
What Fe brings to Fi
Let’s recall Fe’s responsibility to maintain a pleasant social atmosphere, as well as to connect with others on a personal, emotional, and human level. This is what Fi needs: to be listened to, considered, and respected.
Fi users know what they like and what they dislike, as well as how they feel (morals and things they hold dear). However, this can be seen as selfish or too irrational for others. This is where Fe comes in: paying attention to Fi, accepting them, and making sure Fi is comfortable and doesn’t create conflict with people who don’t understand them.
Fe knows what Fi wants and acts accordingly. In this way, Fe builds a relationship of trust and understanding with Fi, and knows how to get along with them. More than mere kindness, these behaviours serve to build trusting and lasting relationships with almost anyone. Moreover, if Fi slips up and becomes immature, Fe will be able to step back, take a more objective view of values, and use ethics to reframe Fi.
What Fi brings to Fe
In order for Fe to act, they need to know the needs of others. Fe derives pleasure from getting along with others and what they like. Even if Fe may have their own values and fight for them, Fi will respect subjective opinions the most, and will base their own identity on them and will not hesitate to talk about them. This regular exposure of Fi’s values will therefore be easily visible to Fe, who will then easily be able to build a relationship with Fi. In return, Fi will be grateful to Fe.
Moreover, Fi’s moral values can easily be transmitted to Fe, transforming the Fe user into someone who is not only ethical (objective values), but moral (subjective values), with their own ideasFi will then be Fe’s moral compass.
Reciprocal benefits
Individuals with very present Fe – Fi compatibility will find themselves in a relationship based on a very deep emotional connection and an almost perfect understanding of the other’s states, giving way to a relationship of trust and sincerity.
When one of the two has difficulties, they will be able to count on the other for all the necessary comfort so that negative emotions do not hinder happiness. In some cases, they will transform these emotions into strength. The activities in which they will engage will originate in the personal values of this couple (Fi), and will benefit a collective (Fe).
Compatibility Se – Si
Relationships mainly based on this compatibility: xSxP with xSxJ
What Se brings to Si
Si users are sensitive to their experiences, remember them, talk about them, consider them before making choices, and act to make them enjoyable for themselves. That’s why they value comfort, and feeling taken care of.
Once again, who else but the extroverted function can perfectly satisfy the needs of the introverted function? Who else but Se can take care of Si?
Se users love to impress, to show, to be noticed, to make people laugh, to be totally present, and to enjoy with others what the environment has to offer in the present moment. They like to spend good times with others and to be the master of the given experience.
Si users are very sensitive to all these new experiences, activity ideas, and novelties given by Se and will love spending time with them. Once the Se user has fully understood the Si user’s subjectivity (that is to say every favorite experience or even the preferences in these experiences that the Si user likes which often become habits), the Se user will try to broaden Si’s vision so as not to let the Si user sink into routine.
In response, the Si user will be very grateful for the Se user’s gifts and will hold onto them over time—sometimes in order to make new habits—for him or them both.
What Si brings to Se
Se users love new activities and ways to engage directly with the real world. They want to constantly discover, explore, go on adventures and face the unknown as if this was their only reason to live. Because of this, the Si user’s influence will play a role by bringing, or more often simply by suggesting to the Se user, certain activities that are often of high quality.
The Si users always remember the experiences they have lived, as well as the best experiences that Se users could (or already have) enjoyed. This calms the Se user in its madness to go looking for the right experience since Si already knows how to reach it.
On a more social level, Se users like to have a good time with others, and for this they need people who will fully appreciate the experience they have offered. No one other than Si users, being aware only of their experiences, will appreciate this as much. And in response, they will give their loyalty and trust to Se users. Once again, Si users are the necessary dose of stability in Se users’ life, bringing trust and habits that will offer comfort to this couple.
Reciprocal benefits
Two individuals who have created a relationship based on compatibility Si – Se will definitely know how to have a good time together. Between Se users who will open the field of action of Si users to new horizons, and Si users who will offer Se users the best of what they have experienced, they will continually balance their relationship in the physical realm.
Whether it is for traveling, the discovery of unknown landscapes, sex, or simply routine activities, Se will bring something new to Si who will enjoy it fully. Then Si will give Se all the stability, order, and loyalty in order to rest.
Compatibility Ne – Ne
Relationships essentially based on this compatibility: xNxP with xNxJ
What Ne brings to Ni
Frequent Ni users constantly know what they want and are aware of their intentions and short and medium-term goals. They therefore need people who are interested in their desires, but who will also provide them with quality help in achieving their goals.
Ne is the intuition brought to the outside world, and therefore allows Ni to understand, analyze, and imagine the many scenarios that could take place in the future. Ne’s vivid and conceptual understanding of what is happening or what will happen is a gold mine for Ni. Thus, Ne users will often alert Ni users of the problems they may encounter in pursuing one or more of their desires, offering them alternative thoughts or actions.
Ni users quickly find themselves submerged in so many ideas, from the very weird ones to the genius ones. With a Ne partner, they only have to filter ideas and to choose one to act on..
What Ni brings to Ne
Ne is capable of many things when it comes to imagining perfect plans, alternatives to complex problems, and making abstract links between different concepts. (Even if it means distorting reality, simply out of curiosity.)
However, this intuitive power is all too rarely used for its own sake. The flexibility and alertness of Ne users makes plans too volatile to be sustained over time. To help Ne users focus their minds on well-chosen elements, they will follow the intentions and well-defined visions of a Ni user. Through Ni users’ will, Ne users will see themselves acting for a cause or plan, and thus give meaning to their ideas and creativity.
Reciprocal benefits
A couple based on this compatibility will often see themselves as ambitious, dreamy, future-oriented and never lacking in craziness. The Ni user will see the perfect future for their relationship while the Ne user will use their imagination to serve this plan. Ni’s tendency to be closed-minded will be compensated by Ne’s freedom of ideas, which will act to meet Ni’s desires.. Ni will give a deep meaning to Ne’s sometimes risky life. With good communication and regular work not to lose their sense of reality, this couple can go crazy (in a good way).
Let us not lose sight of the fact that the cognitive compatibilities relating to each relationship will always manifest themselves differently. These compatibilities are valid especially for serious love relationships. And once again, these compatibilities are said to be natural, and cannot replace the work that will be necessary to maintain any relationship, especially since the environment (culture, values, religion, political opinions, etc.) can obviously play a role on the quality of the relationship.
Nevertheless, they are signs that your relationship will have a chance (or even a good chance!) of working.
For friendship relationships, the rules change a little because the mechanics of balance between functions is less present, and relies instead more on the similarity of functions..
Birdy and Compatibility
At Birdy, we use this compatibility theory to connect you with the most naturally compatible people. By understanding your personality type and your cognitive functions, we can help you learn more about how to develop your personality and understand the people around you better.

You can download our app for Android or iOS, or learn more about yourself by taking our personality test and reading more about your specific personality type.
To better understand the compatibilities, you might want to read one of our Flock articles, like The Story of an INFJ + INTP Friendship, which talks about personal examples of these compatibilities in action.