Growing Up

[Nikky]

This is probably a silly thing to ask but I was wondering. I know all of the first six seasons but only a couple of the following episodes of Bonanza. It seemed to me that, after Adam leaving the show, Joe stopped being the playful youngster that he used to be when older brother was still around.

Would it have happened if Adam had stayed? Was it a matter of maturing, growing up and being adult? Or was Joe given the more responsible, mature part of the older brother? Joe seemed so much more serious in the post-Adam episodes. Or am I totally mistaken? Maybe I should add that I am not too familiar with the later episodes.