For me, the difference between movie and book violence is the former is fixed imagery determined by a director and presented as such to viewers; the latter is written by an author but must be interpreted and imagined by readers—every one of whom will imagine something slightly different. That's why there is more censorship of movies and TV than of books.
...[W]e as writers should be conscious of how our imagery affects readers. Ideally, we want them to feel certain ways at certain times all through our stories. That said, being overly concerned about how any one reader might react is detrimental to writing overall and does not prevent a delusional reader's misinterpretation.
Even if the worst happens—your story inspires someone to commit a crime—the ultimate responsibility for those actions is the reader's.
And today, fellow Shortmystery member Anita Page carried the discussion on to the Women of Mystery blog. There, I commented:
...It’s wrongheaded to blame violent books, movies, and video games on face value. One must look into the ultimate messages the writers are trying to send. Are these deep or shallow? Right or wrong? Would they give a sane person the wrong idea?
One of the series that hooked me on crime fiction was Robert B. Parker’s Spenser. Spenser and his friend Hawk are former boxers, capable of inflicting pain and forced to do so from time to time, but neither takes pleasure in it. Both have strategies to keep themselves in check. For one thing, Spenser makes a commitment to Susan Silverman, a psychologist who can help him with moral choices. Hawk, on the other hand, commits himself to no one, does not allow himself to feel much emotion of any kind. Parker shows that one is clearly the better path to contentment.
The Spenser series would undoubtedly teach a sane person not only how to keep violent impulses in check, but also how to develop morality and autonomy.
UPDATE: It's only fair I also examine the negative message sent by Spenser's continued association with Hawk and other killers.