This subject has been discussed a lot around here lately. This conversation was between two robots, one of which could sense human emotions.
“I do not directly experience the possession of a human mind with all its complexities and contradictions, so I do not grasp the mechanisms by which they respond. But, apparently, crowds are more easily managed than individuals. It seems paradoxical. Much weight takes more effort to move than little weight. Much energy takes more effort to counter than little energy. Much distance takes longer to traverse than little distance. Why, then, should many people be easier to sway than few? You think like a human being, friend Daneel. Can you explain?”
Daneel said, “You yourself, friend Giskard, said that it was an autocatalytic effect, a matter of contagion. A single spark of flame may end by burning down a forest.”
Giskard paused and seemed deep in thought. Then he said “It is not reason that is contagious, but emotion. It may be, then, that the larger the crowd, the more easily they are swayed by emotion rather than by reason.”
“Since emotions are few and reasons are many, the behavior of a crowd can be more easily predicted than the behavior of one person can.”