Cory Doctorow made a lot of money writing bleak books about people turning on each other after a disaster:
The central crisis—a nuclear meltdown, a viral pandemic, a breakdown of our networks or computers—is turned into a catastrophe when the other people around your characters turn out to have been beasts all along, their vicious true natures barely kept in check all these years by the fragile veneer of civilization. Your character might be part of a team, but they’re still a small band of heroes fighting against a brutal and vicious world.
This is the thought experiment of a thousand sci-fi stories: When the chips are down, will your neighbors be your enemies or your saviors? When the ship sinks, should you take the lifeboat and row and row and row, because if you stop to fill the empty seats, someone’s gonna put a gun to your head, throw you in the sea, and give your seat to their pals? I’ve committed this sin myself. Right at the start of the first novel in my Little Brother series, a character gets stabbed in a crowded subway by someone who is apparently just knifing people at random in a crowd. That’s never explained, and no one has ever asked me about it. It’s just people being awful.
But now he wonders if books like his are part of the reason Americans have no faith in each other:
Made-up stories, even stories of impossible things, are ways for us to mentally rehearse our responses to different social outcomes. Philosopher Daniel Dennett’s conception of an intuition pump—“a thought experiment structured to allow the thinker to use their intuition to develop an answer to a problem”—suggests that fiction (which is, after all, an elaborate thought experiment) isn’t merely entertainment.
I wonder about this, too. Our culture is saturated with stories about the Purge, a day on which the law is suspended and all our neighbors turn into murderous fiends, or scenarios like the Walking Dead, in which the zombies are a weak threat compared to the way our fellow humans act once the government is gone. Is that helping to make us paranoid? Or do we like those stories because we already have a streak of paranoia?
Or maybe it doesn't mean anything, any more than Dracula stories mean we want to be threatened by the Undead.
Personally I think the real-life crime surge of the 70s and 80s, and the way it was covered in the news, did a lot more to make Americans fear each other than zombie stories. But I have to wonder about the almost automatic assumption of our movies and television series that ungoverned people will turn into monsters. Why do we enjoy believing that about each other?