Hi Mortiz,
I am not sure about articles on the change in writing style, but I still think Irving is pretty fresh. People are still writing American Gothic (and in particular Southern Gothic) today. The definition of the style, based on Wikipedia (I know... but it was a quick reference), is as follows
"American Gothic Fiction is a subgenre of gothic Fiction. Elements specific to American Gothic include:Rationality/rational vs irrational, puritanism, guilt, Das Unheimliche (strangeness within the familiar as defined by Sigmund Freud), abhumans, ghosts, monsters, and domestic abjection. The roots of these concepts lay in a past riddled with slavery, a fear of racial mixing (miscegenation), hostile Native American relations, their subsequent genocide, and the daunting wilderness present at the American frontier."