„Crowds being only capable of thinking in images are only to be impressed by images. It is only images that terrify or attract them and become motives of action.
For this reason theatrical representations, in which the image is shown in its most clearly visible shape, always have an enormous influence on crowds. Bread and spectacular shows constituted for the plebeians of ancient Rome the ideal of happiness, and they asked for nothing more. Throughout the successive ages this ideal has scarcely varied. Nothing has a greater effect on the imagination of crowds of every category than theatrical representations. The entire audience experiences at the same time the same emotions, and if these emotions are not at once transformed into acts, it is because the most unconscious spectator cannot ignore that he is the victim of illusions, and that he has laughed or wept over imaginary adventures.
Sometimes, however, the sentiments suggested by the images are so strong that they tend, like habitual suggestions, to transform themselves into acts. The story has often been told of the manager of a popular theatre who, in consequence of his only playing sombre dramas, was obliged to have the actor who took the part of the traitor protected on his leaving the theatre, to defend him against the violence of the spectators, indignant at the crimes, imaginary though they were, which the traitor had committed.  We have here, in my opinion, one of the most remarkable indications of the mental state of crowds, and especially of the facility with which they are suggestioned. The unreal has almost as much influence on them as the real. They have an evident tendency not to distinguish between the two.“Gustave Le Bon, The Crowd: A Study of the Popular Mind (1896.)
 Gustave Le Bone speaks of theatre (the book was published in 1896.), but with a clear conscience, we can replace theatre for cinema
 For example, Oliver Stone’s film Natural Born Killers inspired a stream of murders
 This has obviously changed, actors today are admired for great performances as villains (desensitization to such images)