Expressions like this is why most people should stay off of Chatroulette.

Horror films make for especially animated audiences. Moviegoers laugh nervously, cower in their seats, cover their eyes and even talk back to the screen.

This is the biggest difference between horror and drama, says Joe Swanberg, who contributed to the new found-footage horror anthology “V/H/S.” It’s the first time Swanberg, who normally makes eloquently understated dramas including “Alexander the Last” (2009) and “LOL” (2006), has tried to frighten viewers.

“Coming from the world of drama,” he says, “the visceral crowd response has been a real pleasure.”

“V/H/S,” arriving in theaters Friday, is an anthology of found-footage short films by some of the most imaginative young directors working in the horror genre, including Ti West, Adam Wingard and David Bruckner. Those three have made some of the best and most original horror films of the past five years, including “The House of the Devil,” “A Horrible Way to Die” and “The Signal,” respectively.

Of the nine co-directors of “V/H/S,” Swanberg is the odd man out. “My past body of work,” he admits, “does not make me an ideal candidate to direct one of these.” Yet his segment of the film, “The Sick Thing That Happened to Emily When She Was Younger” — which is told entirely through Skype — is one of the movie’s most terrifying.

Swanberg is excited to be in such good company. “V/H/S” he says, may be “really grisly and in a lot of ways very immature, and it has a lot of the blood and nudity of the ’80s horror aesthetic, but it’s a really smart movie,” he says. “These directors are some of the coolest, smartest people making horror movies today. These guys are going to revolutionize the genre.”