Pick any news story and a journalist (from an outlet like NYT, Politico, etc).
Watch the timeline of that journalist's original opinions (and their level of aggression/assertiveness) and then watch how that cascades to either more extremism—if the evolution of the story agrees with their chosen narrative—or, to absolute abandonment of/ignorance of the thing they so fervently held an opinion about a few hours earlier.
Once you start observing this behavior, you will see it happen for nearly all stories. It's like watching rats press a lever to release food pellets and then scattering off to a corner to digest.
I don't know of any good article on the subject, but I think the red/blue war in America is where you can see some of the most extreme examples of this. A simple illustrative example that comes to mind: A politician on the other side of the aisle makes a gaffe, a journalist amplifies the video/text of their statement, based on their followers' reaction a journalist decides if it's something their followers care about and either writes a piece about it with supporting information about just how wrong they are and takes on it from their followers/colleagues or just ignores it and moves on trying to find more red meat for the political partisans that read them.
I've seen this play out time and time again. An environment like Twitter only encourages echo chambers and actively promotes the blocking of content and opinions a person might find inconvenient. If the average Twitter user wants to build themselves a little fantasy land making themselves stupider everyday that's their perogative. But if they consider themselves a journalist it becomes a real problem. Good journalism should have some basis in reality and ideally should involve going out and talking to people. It shouldn't be a work of fiction made to order for a tiny (yet significantly over represented) subset of the population.
Watch the timeline of that journalist's original opinions (and their level of aggression/assertiveness) and then watch how that cascades to either more extremism—if the evolution of the story agrees with their chosen narrative—or, to absolute abandonment of/ignorance of the thing they so fervently held an opinion about a few hours earlier.
Once you start observing this behavior, you will see it happen for nearly all stories. It's like watching rats press a lever to release food pellets and then scattering off to a corner to digest.