I still remember the first time, when I decided to use an outside model to help me understand people. The first model that I tried was an astrological one. You know, the one where the time and hour of birth was supposed to give you certain traits.
It ended up badly. I was desperate, so I am sure that I had a relatively high conformation bias. But the predictions that I could made from the sun signs of people around me were not in accordance with my observations.
It might also be, that my and my mother have the same astrological sign, but we are only partly similar.
I then started to ask people around, to try and predict the sun sign of my and other people around me. For some reason, most if not all of them were wrong. None of them said cancer, which is my sun sign. Most frequent was Libra | my moon sign) or scorpion | my Pluto sign). But if they can just guess, and it has to me in one of my signs, then they have a more than 50% to get it right. So, I can't really take this into account. Especially, since the results were pretty similar for guessing other people.
They always told me that I need to know their exact charts to be able to understand people. Since I could not find out a practical way at the time how to so it, I found it useless for my endeavour. I needed something that will help me understand people without leading them through the structured interview before.
Though, there are some supposed correlations with astrology and personality. For example, the people with the sun sign in the fire and air sun signs tend to be more extroverted. The people with the sun signs in earth and water tend to me more introverted. Though it is hard to tell, how much does the knowledge of astrology impacts this.
But even as I got more generally interested in the differences in people, I never really invested the time again in the astrology. And the reason for that is the mentality of people that practice or believe in it. I might just meet a small subset of people that were interested in the astrology, but they were a bit... cultish?
What I mean by that is, that they always tried to explain things away, and never were really interested in studying things in a more self-directed manner. The astrology was what the books were telling them, not what the reality was. And all inconsistencies with realities were explained that even they don't know everything that is in the books yet.
If it reminds you of some people... well, they are like these religious fanatics that try to explain everything with the bible. So, not really something that I want to be a part of it. Even if they were not as pushy as the religious folks.
So these are the main reasons, why even though I was interested in personality for years now, I never really got deep in the astrology. Even though it is the most frequently used personality type model. And considering that these reasons are a bit similar to the ones mentioned in Thagard article, I think that I still mostly did the right choice.