One idea that is really strong in the MBTI community is, that the forth function is the one that people need to develop. It is supposed to be the function that represents the ultimate goal and it is also one of the weaker, if not the weakest function. Well, I always had problem with the weakest denominator, but I will admit that it is weak.
Here is a table for each type and what it their forth or anima function:
|INTP, ISTP||Fe||ESTJ, ENTJ||Fi|
|INFP, ISFP||Te||ESFJ, ENFJ||Ti|
|INTJ, INFJ||Se||ENFP, ENTP||Si|
|ISTJ, ISFJ||Ne||ESFP, ESTP||Ni|
And even when asking people around, or simply observing them, it can be seen that this is the function that is weak for them. For me, an INTP, Fe is the weakest function. I know, because even now I still use Ti to try and navigate the social interaction, in order to try and achieve the Fe like state. Let me tell you, it is not working well, and it exhaust me. On the other hand, the Fe in me can force to start nothing things that I am not sure that I want to notice. The reason for this is, that it than makes me stop from doing the things that I want, because I can see the effect it will have on other people. It is annoying, and just from this description you can see that I don't have a healthy relationship with this function.
I also tried to ask people to see if this also holds true from them. An INFJ I know told me, that they are having problem with observing the current environment, so with Se, and that they are trying to improve it. An ENFP told me, that she is having a bit of problem listening to her body and she is kind of obsessed with her health. And she can continue doing what she has been trying for a while, which is more of a sign of Si then her usual Ne. An ESTP that I know once told me, that they have a problem with very abstract and unpractical ideas, which is a domain of mostly Ni.
I could probably find additional example, but I think this shows that this have at least a potential of being right. But then the next question is, how to work on developing these additional function.
One think that I have found useful, is to simply be put in the situations, where it is impossible to use the function, which you are already good at. But these environments are hard to find, because that means that you would need to find more and more unsolvable situations to be in. But to me, this had helped more than doing the function-specific activities, because these do not really exist. I will show you what I mean.
There are activities that are connected with different functions. Sport and eating for with Se, solving puzzles with Ti, mathematics with Ni and Ti, organizing the space with Te, brainstorming with Ne and writing poetry with Fi, envisioning the future with Ni, reminiscing about the past with Si and meeting people with Fe. These are just the ones that I can come up with the top of my head. The problem is, that each activity can be done in a function specific way.
Let us take the example of being concentrated on eating food. The Se types will enjoy in the moment and experience the taste of food. The Si types will connect this food with their memories. The Ne types would get a couple of ideas while eating food, which would start with food, but it might not end with one. Ti types might try to figure out what the food is made of. And so on. Each activity can be done in a function specific way.
That is why I suggest to inhibit the functions that you normally use. So, I as an Ti type, that means that I either need to be in the situation, where the linear nature of the Ti type is not quick enough to be able to solve the problem, because there is too much input and new puzzles to solve. The case of that was me living in a foreign country for the first time, where there was just too many things to figure out, so I naturally started to use Ne a lot more. When I was a teacher in Hungary, most of the people around me at this school had Fe as a strong function, so my Ti solutions did not work. So I ended up using weird mixture of Ti and Fe. Last year in Austria, I had the problem that I did not know how to solve even after days of thinking about it, when suddenly I saw the solution using Ni.
Sure, in everyday life this situations are a bit hard to develop. So, the other way to do it would be to simply try and use a different function to solve a problem. But since the first function is such an integral part of the identity, I so far had no success with it. But maybe you guys will.