"Thousands of isolated individuals may acquire at certain moments, and under the influence of certain violent emotions—such, for example, as a great national event—the characteristics of a psychological crowd. . . .
The most striking peculiarity presented by a psychological crowd is the following: Whoever be the individuals that compose it, however like or unlike be their mode of life, their occupations, their character, or their intelligence, the fact that they have been transformed into a crowd puts them in possession of a sort of collective mind which makes them feel, think, and act in a manner quite different from that in which each individual of them would feel, think, and act were he in a state of isolation."
Gustave Le Bon
MASS PSYCHOLOGY
http://historymuse.net/readings/LeBonMASSPSYCHOLOGY.htm