@flynny, he is correct in saying it is done automatically, but you sound like you may be somewhat new to programming. $title is a variable, it is not constant, you can only change it in that code once you have some condition stop on a piece of information you want to change in a situation you determine in a conditional structure. That is why it is called ‘the loop’, each time it loops, it fetches another post, and the information stored in $title or any of the other variable are potentially and most likely different. In each situation that $title value will be whatever it was set to in the WordPress’s GUI back end. So I think what you might have wanted to know is that you don’t have to change it there, you do it in the CMS.
I could well have misinterpreted you since there’s not a whole lot of information to go by. I hope it was helpful just the same.