Philosophers such as Le Bon, Durkheim, and Tarde analyzed crowd phenomena in detail, focusing on the psychological characteristics of its individuals. They described the law of mental unity, where emotions, beliefs, interpretations, intentions, and actions converge unanimously.
This convergence gives rise to a feeling of irresistible power and an idea of irresponsibility. Crowds are subject to sudden, simple, extreme, intense, and changeable emotions. Although capable of thought, their ideas are simplistic and their reasoning rudimentary, converging as one man.
Crowd behavior is explained by mental contagion and the influence of leaders. Mental contagion suggests that emotions and opinions spread, multiply, and reinforce each other. The role of leaders is crucial, because "every crowd needs leaders." Direct observation of collective behavior reinforces the idea that the leader, who acts through assertion, repetition, and contagion, owes their authority to their prestige. This prestige is a "faculty," independent of any title or authority, a "fascinating power," a power of "truly magnetic fascination" such as an artist in communion with their audience can have.
