Yes, they did. Don't know about theaters anymore, as I rarely go to them, but back in the late 70's early 80's, roughly Halloween through A Nightmare on Elm Street, it wasn't unusual to hear screaming or see some popcorn go flying during horror films. One I will never forget is a girl running out of the theater during the beginning of Friday the 13th Part 2 when they were simply recapping Part 1. It was the scene when Jason ambushes the canoe. She screamed, ran out of the theater and didn't come back. Got the feeling she missed the ending of Part 1 or missed all of Part 1.

But it was different back then. It was the slasher craze. Not a lot of adults, if any, would be in the theater as they thought those kinds of movies were stupid and they were right. The movies were stupid but going to one was an experience. We ("Look, Frank, Teeny Boppers") ruled the theater in our small town on Friday nights. We'd yell at the characters on the screen, tell them they were being dumb or it'd be totally quiet building up to something, someone would yell something out, we'd all laugh breaking the tension for a sec, then BOOM jump scare/graphic kill, popcorn flies and screams. When I tell people I love slasher films that's a big reason why. It the nostalgia. Going to see one with a bunch of friends in packed theater was a blast. Unfortunately, I think that experience is gone forever. The last time I really remember a scream at the theater was the bedridden, drug addict guy in Seven. That's a long time ago but that scene got the crowd going.