This should be something that is easy to study! There are many parents with multiple kids (I am one!) and they can tell you if all of them were just a tabula ra

This should be something that is easy to study! There are many parents with multiple kids (I am one!) and they can tell you if all of them were just a tabula rasa with no personality or if they were all different on day one. I will say that all of mine were. Of course environment guides how they grow but the way they interact and interpret the same environment seems to be different.