I tend to agree with Ebbie and Bill, but the influence on society may be far more subtle and not directly related to violent behavior.

Consider: Japanese "graphic novels" (i.e., expensive comic books with more pictures and less talk than when they cost 1/10 the price) are relentlessly, horrendously violent in comparison with ours - and incredibly popular. Yet the Japanese murder rate is minuscule (they don't have guns, but they could find other ways to kill one other if they really wanted to.)

There have been numerous studies carried out since the '60s. Kids and grownups are shown violent films, etc., then their behavior is monitored in various ways. One experiment staged a fistfight a minute or two after exposure. In that one, it was discovered that people who'd watched the violent videos were actually more passive in a sense than those who hadn't: those who hadn't tried more often to stop the fight, while those whose brains were filled with violent images tended just to watch.

Tests with kids showed that watching violent cartoons seemed to have no overt effect. Watching violent actors made them more aggressive - but aggression is often defined as yelling or pushing, not getting truly violent like punching or kicking or even fighting.

If I recall correctly, there was a '70s study of men who preferred sadistic pornography over the other kind. Turns out they weren't notably more violent or aggressive than anybody else. IIRC.

I don't know about long-term studies. You'd think that watching 20,000 acts of murder and violence on TV alone by the time you're 18 (as was estimated in the '70s - it's probably more now) would have *some* kind of effect. But what? And on whom?

...if on anyone at all. Somebody must know more about this topic than I do.