“You know, I don't think I've got it in me to shoot my flatmate, my mum, and my girlfriend all in the same night,” says Shaun, one of the beleaguered non-ghouls in Shaun of the Dead. That 2004 film is a send-up of zombie movies, but you know what they say about every joke containing truth.  

Ever since director George A. Romero released his 1968 shocker Night of the Living Dead—which reimagined zombies, the dark magic-entranced slaves of voodoo folklore, as shambling fiends that crave warm flesh and can only be offed with a head shot—the zombie genre has displaced the western as cinema’s most popular and durable morality play. As the video essay “Zombie 101” demonstrates, while the genre’s superficial appeal is the spectacle of torn and mangled flesh—living and dead—its deeper resonance lies in its portrait of ordinary people struggling to survive in extreme circumstances.  

Ultimately zombie films aren’t about the zombies, which have no conscious mind and therefore no personality. They’re a collective menace—rotting emblems of plague, catastrophe, war, and other world-upending events.  The films depict representative social types wandering amid the ruins of the civilization they once took for granted, trying to reconcile their pre-zombie moral code (do unto others as you would have them do unto you) with the harsh necessities of the present (“If you’ve got a gun, shoot ’em in the head,” a sheriff tells a TV reporter in Night of the Living Dead, adding, “If you don’t, get yourself a club or a torch. Beat ’em or burn ’em, they go down pretty easy”).  

If there’s no military, no police force, no law, no justice, and no hope, what’s the point of being decent as opposed to selfish? Might it be possible that, under such unimaginably awful circumstances, selfishness is decency? And if your mom is bitten by a zombie, at what point is it all right to stop treating her like your mom and reach for the 12-gauge? Dear Abby never had to ponder such questions. To quote the alternative title of a 1974 Werner Herzog movie, in zombie films it’s every man for himself and God against all. And as survivors sift through the rubble, weighing selfish imperatives against kinder, gentler impulses that might get them and everyone around them killed, the genre pulls off a nifty bit of creative jujitsu, defining civilization, morality, stability, and decency by depicting their opposites.