I have a hard time believing that, though I suppose the human consciousness is still a big mystery, despite socionics.
Infants and children act based on their genetics.
Then, as they grow, they develop skills accordingly, based on their temperament, background, their parents' inferior functions, etc.
Even as a child, I was very quiet and appeared very solemn and low-key in photos, even though I am quite perky nowadays. I was extremely Infp when I was younger. It seems to be my natural state, or maybe my neutral state. Hmm. But if I am indeed more Intj now, it is because I was so traumatized by my emotions and other people's decisions that I have no other choice but to build an iron wall and execute an Intj image.
So, is it possible that somewhere during childhood and adolescence, one's type could change due to the impact of their environment and the people they are with? Is there a easier, straight-forward explanation of type change?
Is it possible for an INFP child to become quickly an INTJ based on emotional trauma?
Also, I can tell other people's types by photos. But we pretty much look exactly like our baby photos, just bigger. So an INFP child couldn't grow to have such sharp and cold features as an INTJ no matter the experience.
Or maybe, we were all born a certain type but eventually we all learn to put up public/professional images. I may be going back to firmly believing that our types don't change. We just become less natural in our personality and more consciously designed, in order to survive.