"If someone has a very strong reaction to specific things they see, it might be that it reminds them of a trauma," Pluess said. "It might be more than sensitivity, it might be a fear response — a blood phobia, a dog phobia."

For those who do feel the reverberations of media violence more thoroughly, these can be trying times to go to the movies, Pluess said. Consider recent offerings such as the horror film "Texas Chainsaw 3D," in which a man is dragged into a meat grinder or the Sylvester Stallone action film "Bullet to the Head," in which a bullet speeds toward the audience in the opening credits.

"As a society we've gotten habituated to special effects, 3-D — the filmmakers are trying everything possible to help us forget this is a film," Pluess said. "For people who are more affected by what they can see, they might struggle to realize they are not part of the film."

Hollywood studios are aware of different peoples' sensitivity to violence, according to Vincent Bruzzese, president of the motion picture group at the market research firm Ipsos, and they try not to blindside audiences with misleading marketing — sending someone expecting a cerebral thriller to a gory horror film, for instance. But ultimately the studios' decisions are governed by the marketplace.

"If [violence] didn't make money, studios wouldn't make these movies," Bruzzese said. "It comes down to what's the biggest audience we can get for the best film we can make. The studios would put out a four-hour documentary about how to garden tulips if they thought they'd have a $100-mil opening weekend. But it doesn't work that way."

THE CULTURE OF VIOLENCE:  Art | Film | Television | Hollywood 

Pluess does see a potential upside for the sensitive among us. He recently conducted a pilot experiment in which he showed two film clips to a group of 90 people — one was a humorous scene from the romantic comedy "When Harry Met Sally," the other a scene in which a character died in the boxing drama "The Champ." After watching the clips, the group had to rate their feelings.

Some were unaffected, some deeply so. The people who had the strongest negative response to "The Champ" were often the same ones who had the strongest positive response to "When Harry Met Sally."

"It's not just that some people are more affected by violence — those same people enjoy more the benefit of a film," Pluess said. "When there's a romantic moment or a funny moment, they feel it more too."

rebecca.keegan@latimes.com