“I think it’s a no-brainer and crystal clear,” said James Steyer, the chief executive of Common Sense Media, a watchdog group, saying that he believed there was a demonstrated link between violent entertainment and behavior.

Mr. Steyer acknowledged that several studies highlighted by the Entertainment Software Association, a game industry group, had found no clear causal connection between violent programming and violent behavior. But last year, he noted, reports by his organization and federal researchers responding to a request by President Obama after the Newtown massacre found evidence of a correlation that is still not entirely delineated.

“Significant relationships exist between violent media experience and some measure of aggression and violent behavior,” said the federal report, which was prepared by the Institute of Medicine and the National Research Council.

More pointedly, both reports said that contemporary entertainment media — including social media, intense interactive online experiences and role playing that can spill from screens into life, as with the costumed fans at Comic-Con — have far outstripped the research into their possible impact. In other words, the entertainment industry is moving too fast for the researchers to keep up.

Studies on the matter do tend to move with a glacial speed. As part of a series of executive orders about 18 months ago, Mr. Obama asked Congress to give the Centers for Disease Control and Prevention $10 million annually to research the root causes of gun violence in America. A bill was finally introduced last month, but it faces Republican opposition.

In the interim, movie studios have continued to rely on violence for hits. It worked last weekend for Universal Pictures, which released “The Purge: Anarchy” to a hefty $29.8 million in ticket sales. This summer, Sony successfully sold “22 Jump Street” with ads featuring goofball cops holding gold guns. Next up: Marvel’s “Guardians of the Galaxy,” which arrives on Aug. 1 and features a machine-gun-toting raccoon.